Discussion:
rack mount power conditioners
(too old to reply)
Steven Shelikoff
2003-12-25 01:46:04 UTC
Permalink
I'm putting together a little rack for live performance and like any
good consumer, I'm checking out the surge and spike specs for power
conditioners. I want to protect my investment. I need only 15 amps but
am looking at the 20 amp ones as well if the price is right. Some form
of EMI/RFI noise supression is required but I'm more interested in
protecting the equipment from unknown power sources then getting rid of
that last little bit of noise. Bells and whistles like volt meters,
ammeters, lights, etc. are nice but not really required.

Let me know if I have my terms right because they're pretty confusing.

Clamping voltage: the highest voltage the equipment should see when a
spike hits. The lower the better.

Response time: the time a surge protector has to "kick in". The lower
the better. On the order of 1 nanosecond is common.

Those first 2 determine how well the surge supressor protects the
equipment. The next 3 determine how well the surge supressor protects
itself.

Max voltage: highest single voltage spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.

Max current: highest single current spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.

Max energy: cumulative amount of energy from all of the spikes the surge
protector has seen before it's clamping voltage spec increases by 10%.
The higher the better. This one determines pretty much how long the
surge protector will last in normal service compared to other surge
protectors if they never see *really big* spikes that exceed the max
voltage and max current.

Hopefully I have all those things correct above. If not, please feel
free to correct me. Now on to the numbers from the manufacturer's
literature. For each model the numbers are given in the order above:
clamping voltage, response time, max voltage, max current and max
energy. Also, the last spec is noise attenuation (higher the better).

ETA PD8/PD8L
330V, < 1 nanosecond, N/A, 65000A, 1665 joules, up to 68 dB
150kHz-100MHz

ETA PD9L
N/A, 1 nanosecond, 6000V, 12000A, 450 joules, >35 dB 1.5kHz-200MHz

ETA PD11LV
330V, < 1 nanosecond, N/A, 6500A, 630 joules, up to 20 dB 150kHz-200MHz

ETA PD11SS
200 V, 1 nanosecond, 6000 V, 12000 A, 450 joules, >35 dB 1.5kHz-200MHz

ETA PD11P
200 V, 1 nanosecond, 6000 V, 23000 A, 630 joules, >20 dB 1.5kHz-200MHz

ETA PD11SP
200V, 1 nanosecond, 6000 V, 26000 A, 630 joules, >35 dB 1.5kHz-200MHz

ETA PD11LVSP/PD11SSP
200V, 1 nanosecond, 6000 V, 26000 A, 630 joules, >20 dB 1.5kHz-200MHz

Furman PL-PLUSD/PL-PLUSDM/PM-8DM
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, >40 dB 1MHz-200MHz

Furman PS-8/PS-8R/PL-PLUS/PM-8
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, 20dB 200kHz, >40 dB
1MHz-200MHz

Furman PL-8
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, N/A

Furman PL-PROD/PL-PRODM/PM-PRODM/PM-PRO/PS-PRO/PL-PRO
400 V, 1 nanosecond, N/A, 11000 A, 550 joules, >40 dB 1MHz-200MHz

Furman RR-15NL/RR-15/RR-15-PLUS
N/A, N/A, N/A, N/A, 102 joules, >20 dB 1.5MHz-200MHz

Furman RP-8/RP-8L/RP-8D
250V, N/A, N/A, 4500A, 102 joules, >20 dB 1.5MHz-200MHz

Nady PCL-800/PCL-810/PCL-815
N/A, N/A, N/A, N/A, N/A, N/A

Powerwerks 1630
250 V, 1 nanosecond, N/A, 19500 A, 240 joules, 20 dB at 200kHz

Samson PS9/PB9/Pro7 (from the owners manual)
340 V, 1 nanosecond, N/A, 4500 A, 56 joules, > 20dB 1.5MHz-200MHz

Samson PB9 (from brochure)
400 V, 1 nanosecond, N/A, 8000 A, 85 joules, > 20dB 1.5MHz-200MHz

And just for comparison sake, my $10 15amp power strip:
330 V, N/A, N/A, N/A, N/A, 510 joules

What is Nady hiding? They don't give any specs in their literature.
The Samson has nice features like the tray but at 56 joules, it won't
last long before you have to replace the surge suppression components.
Why can't Samson get their specs consistent?

The Furmans, which I see everywhere, have a high clamping voltage
(except for the older RP line). Correct me if I'm wrong, but I don't
think they can even pass UL certification with clamping voltage that
high. They are also middle of the road in terms of how much spike
energy they can absorb.

The ETAs look like the best overall supressors with the cheap Powerwerks
coming in a close second. My $10 power strip does a pretty good job as
well but I don't think it has any EMI/RFI filtering at all.

Anyone have any comments, recommendations? Why do I see Furmans all
over the place? Is it just marketing?

Steve
Craig Ruggels
2003-12-25 04:08:35 UTC
Permalink
Hi Steve,
Have a furman plh-15 for 3years and now problems. Use it in my home studio.
Have just purchased a furman pl plus for my remote gear and love the line
reduction

hopr that helps
Craig
MeadowView Music
Post by Steven Shelikoff
I'm putting together a little rack for live performance and like any
good consumer, I'm checking out the surge and spike specs for power
conditioners. I want to protect my investment. I need only 15 amps but
am looking at the 20 amp ones as well if the price is right. Some form
of EMI/RFI noise supression is required but I'm more interested in
protecting the equipment from unknown power sources then getting rid of
that last little bit of noise. Bells and whistles like volt meters,
ammeters, lights, etc. are nice but not really required.
Let me know if I have my terms right because they're pretty confusing.
Clamping voltage: the highest voltage the equipment should see when a
spike hits. The lower the better.
Response time: the time a surge protector has to "kick in". The lower
the better. On the order of 1 nanosecond is common.
Those first 2 determine how well the surge supressor protects the
equipment. The next 3 determine how well the surge supressor protects
itself.
Max voltage: highest single voltage spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.
Max current: highest single current spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.
Max energy: cumulative amount of energy from all of the spikes the surge
protector has seen before it's clamping voltage spec increases by 10%.
The higher the better. This one determines pretty much how long the
surge protector will last in normal service compared to other surge
protectors if they never see *really big* spikes that exceed the max
voltage and max current.
Hopefully I have all those things correct above. If not, please feel
free to correct me. Now on to the numbers from the manufacturer's
clamping voltage, response time, max voltage, max current and max
energy. Also, the last spec is noise attenuation (higher the better).
ETA PD8/PD8L
330V, < 1 nanosecond, N/A, 65000A, 1665 joules, up to 68 dB
150kHz-100MHz
ETA PD9L
N/A, 1 nanosecond, 6000V, 12000A, 450 joules, >35 dB 1.5kHz-200MHz
ETA PD11LV
330V, < 1 nanosecond, N/A, 6500A, 630 joules, up to 20 dB 150kHz-200MHz
ETA PD11SS
200 V, 1 nanosecond, 6000 V, 12000 A, 450 joules, >35 dB 1.5kHz-200MHz
ETA PD11P
200 V, 1 nanosecond, 6000 V, 23000 A, 630 joules, >20 dB 1.5kHz-200MHz
ETA PD11SP
200V, 1 nanosecond, 6000 V, 26000 A, 630 joules, >35 dB 1.5kHz-200MHz
ETA PD11LVSP/PD11SSP
200V, 1 nanosecond, 6000 V, 26000 A, 630 joules, >20 dB 1.5kHz-200MHz
Furman PL-PLUSD/PL-PLUSDM/PM-8DM
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, >40 dB 1MHz-200MHz
Furman PS-8/PS-8R/PL-PLUS/PM-8
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, 20dB 200kHz, >40 dB
1MHz-200MHz
Furman PL-8
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, N/A
Furman PL-PROD/PL-PRODM/PM-PRODM/PM-PRO/PS-PRO/PL-PRO
400 V, 1 nanosecond, N/A, 11000 A, 550 joules, >40 dB 1MHz-200MHz
Furman RR-15NL/RR-15/RR-15-PLUS
N/A, N/A, N/A, N/A, 102 joules, >20 dB 1.5MHz-200MHz
Furman RP-8/RP-8L/RP-8D
250V, N/A, N/A, 4500A, 102 joules, >20 dB 1.5MHz-200MHz
Nady PCL-800/PCL-810/PCL-815
N/A, N/A, N/A, N/A, N/A, N/A
Powerwerks 1630
250 V, 1 nanosecond, N/A, 19500 A, 240 joules, 20 dB at 200kHz
Samson PS9/PB9/Pro7 (from the owners manual)
340 V, 1 nanosecond, N/A, 4500 A, 56 joules, > 20dB 1.5MHz-200MHz
Samson PB9 (from brochure)
400 V, 1 nanosecond, N/A, 8000 A, 85 joules, > 20dB 1.5MHz-200MHz
330 V, N/A, N/A, N/A, N/A, 510 joules
What is Nady hiding? They don't give any specs in their literature.
The Samson has nice features like the tray but at 56 joules, it won't
last long before you have to replace the surge suppression components.
Why can't Samson get their specs consistent?
The Furmans, which I see everywhere, have a high clamping voltage
(except for the older RP line). Correct me if I'm wrong, but I don't
think they can even pass UL certification with clamping voltage that
high. They are also middle of the road in terms of how much spike
energy they can absorb.
The ETAs look like the best overall supressors with the cheap Powerwerks
coming in a close second. My $10 power strip does a pretty good job as
well but I don't think it has any EMI/RFI filtering at all.
Anyone have any comments, recommendations? Why do I see Furmans all
over the place? Is it just marketing?
Steve
Mike Rivers
2003-12-25 13:27:03 UTC
Permalink
Post by Steven Shelikoff
I'm putting together a little rack for live performance and like any
good consumer, I'm checking out the surge and spike specs for power
conditioners. I want to protect my investment. I need only 15 amps but
am looking at the 20 amp ones as well if the price is right. Some form
of EMI/RFI noise supression is required but I'm more interested in
protecting the equipment from unknown power sources then getting rid of
that last little bit of noise.
They just about all work - once. EMI suppression varies, and I don't
put any more credibility in the EMI specifications that most of the
devices carry any more than I believe "Frequency response 20 Hz - 20
kHz." The surge protection specs are probalby pretty fair, at least
for a brand new unit.

Basically there are two different ways to suppress transients. The
most common (and least expensive) ones use a device whose resistance
drops sharply when the voltage applied to it exceeds a certain
threshold. It shunts the current away from the output, and if things
(the transient and the suppressor device) last long enough, a fuse
or circuit breaker will blow, removing the supply voltage from the
output. The other type of surge protector is in series with the supply
voltage and the output. It works essentially like a low pass filter,
filtering out transients that have a lot of energy for a short time
(high frequencies).
Post by Steven Shelikoff
Clamping voltage: the highest voltage the equipment should see when a
spike hits. The lower the better.
Correct. The trick is for this to work on the second big spike that
comes along.
Post by Steven Shelikoff
Response time: the time a surge protector has to "kick in". The lower
the better. On the order of 1 nanosecond is common.
This isn't hard to meet for a voltage-sensitive resistor. An actual
regulator, something that sits on the line voltage when it goes up to,
say, 140 volts and stays there for more than one cycle, react slower.
Those aren't transients, they're voltage excursions. Same for when the
voltage goes too low.
Post by Steven Shelikoff
Max voltage: highest single voltage spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.
Max current: highest single current spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.
If the surge protector breaks down, it leaves the equipment
unprotected. This is the problem with shunt regulators. It's
compounded by the fact that there usually is no indication that the
transient suppression device has blown, or if there is, it's located
someplace where you aren't likely to notice it.

While you can compare specifications for these parameters, you can't
control the transient. So, yeah, the higher the better, but no matter
how high the rating, there can always be something coming down the
line that will exceed it. There may be some environmental statistics
that can guide you as to how much is likely to be enough for where you
live, but it's still a gamble. I haven't looked at the numbers, but I
suspect that there isn't a lot of difference between units if they all
measure and report honestly. It's not like there's a choice of devices
that they can use to absorb the transient - they're all about the same
within the same device class.
Post by Steven Shelikoff
Max energy: cumulative amount of energy from all of the spikes the surge
protector has seen before it's clamping voltage spec increases by 10%.
The higher the better. This one determines pretty much how long the
surge protector will last in normal service compared to other surge
protectors if they never see *really big* spikes that exceed the max
voltage and max current.
I've never seen this specification, but it seems to describe the life
of the transient absorbing component. I wasn't aware that they
degraded by a small amount like 10%. My experience is that either they
work pretty much as expected (and I'd certainly expect a 10% tolerance
as normal) or they fail entirely.
Post by Steven Shelikoff
What is Nady hiding? They don't give any specs in their literature.
The Samson has nice features like the tray but at 56 joules, it won't
last long before you have to replace the surge suppression components.
Why can't Samson get their specs consistent?
You'll notice that the lower priced units are sketchier about their
specifications. It's possible that they're really very simple inside,
not really different than your $10 outlet strip. It's also possible
that they perform better than shown on paper, but they haven't been
tested very well. It's expensive to test devices that essentially work
by destroying themselves.
Post by Steven Shelikoff
The Furmans, which I see everywhere, have a high clamping voltage
(except for the older RP line). Correct me if I'm wrong, but I don't
think they can even pass UL certification with clamping voltage that
high.
UL certifies equipment for safety, not for how well it works. As long
as you can't easily stick your finger in the socket and it isn't built
so that a fault can easily connect the hot side of the power line to
the case, or it won't burst into flames, it will get UL certification.
Post by Steven Shelikoff
The ETAs look like the best overall supressors with the cheap Powerwerks
coming in a close second. My $10 power strip does a pretty good job as
well but I don't think it has any EMI/RFI filtering at all.
Anyone have any comments, recommendations? Why do I see Furmans all
over the place? Is it just marketing?
Yes, they're well distributed to places that sell to people who are as
worried as you are. ETA does more engineering and more testing, and
also makes products for service outside the music industry. It's why
the prices are higher, but they look a little nicer inside. Have you
looked at the Surge-X product line? Those are series transient
suppressors, cost a lot more than what's presently on your shopping
list, and generally used by people who simply don't want to worry
about something that can be fixed safely for some more money.


--
I'm really Mike Rivers (***@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
ChuxGarage
2003-12-25 15:46:22 UTC
Permalink
I've used quite a few ETA's over the years with good results. They've been in
a variety of fixed and portable applications. All have very straightforward
design, good construction, and fairly reasonable prices.

In fact, an ETA regulating supply currently protetcts my video editing setup.

The Furman products are also quite good, so I guess it is a little like
religion. Find one you like and stick with it.

Chuck
Steven Shelikoff
2003-12-25 18:00:21 UTC
Permalink
[much useful info snipped]
Post by Mike Rivers
Post by Steven Shelikoff
The Furmans, which I see everywhere, have a high clamping voltage
(except for the older RP line). Correct me if I'm wrong, but I don't
think they can even pass UL certification with clamping voltage that
high.
UL certifies equipment for safety, not for how well it works. As long
as you can't easily stick your finger in the socket and it isn't built
so that a fault can easily connect the hot side of the power line to
the case, or it won't burst into flames, it will get UL certification.
I was wrong, the Furmans are UL certified. They just don't claim it in
the literature. But it's on the UL website.

One thing though, UL does consider the performance parameters as safety
related for surge supressors. It's a lot more than just finger in the
socket or burst into flames. There's a lot of info on the web about it.
Here's one:

http://www.currenttechnology.com/paper_8.htm
Post by Mike Rivers
Post by Steven Shelikoff
The ETAs look like the best overall supressors with the cheap Powerwerks
coming in a close second. My $10 power strip does a pretty good job as
well but I don't think it has any EMI/RFI filtering at all.
Anyone have any comments, recommendations? Why do I see Furmans all
over the place? Is it just marketing?
Yes, they're well distributed to places that sell to people who are as
worried as you are. ETA does more engineering and more testing, and
also makes products for service outside the music industry. It's why
the prices are higher, but they look a little nicer inside. Have you
looked at the Surge-X product line? Those are series transient
suppressors, cost a lot more than what's presently on your shopping
list, and generally used by people who simply don't want to worry
about something that can be fixed safely for some more money.
Thanks for the info on surgex. They look really nice. But you're
right, they are a lot more money than I wanted to spend. You pays your
money and takes your chances. The extra money for the surgex buys you
that little area of protection greater than the ones I listed up to
where the surgex itself fails. For me, I'll take the chance that the
"normal" ones like the Furmans and the ETAs will be good enough.

Steve
Mike Rivers
2003-12-26 01:48:38 UTC
Permalink
Post by Steven Shelikoff
One thing though, UL does consider the performance parameters as safety
related for surge supressors. It's a lot more than just finger in the
socket or burst into flames. There's a lot of info on the web about it.
http://www.currenttechnology.com/paper_8.htm
I'll read it some time when I'm not in the middle of cooking Christmas
dinner. I suspect that it has more to do with the suppessor not going
up in flames than your connected equipment not going up in flames.


--
I'm really Mike Rivers (***@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
w_tom
2003-12-26 01:31:20 UTC
Permalink
UL makes no claim that any transient protector works. Their
'agenda' is that the protector does not harm humans. In fact
UL1449 was so poor that only UL1449 2nd edition is considered,
by some insiders, as acceptable. UL1449 being totally about
human safety AND makes no claim to effective transistor
safety. In fact, some UL1449 tests don't even care if
electronics are damage or if protector fails. Those failures
do not affect human safety. Important is that transient
protector does not endanger human life. A problem that PC
magazine demonstrated twice in late 1980 issues.

Noise and hardware destructive transients are two completely
different topics. Electronics already has effective internal
protection from both. Protection that assumes the destructive
transient will be earthed before it can enter the building; so
that internal protection will not be overwhelmed. Details
summarized is previous discussions:
"Opinions on Surge Protectors?" on 7 Jul 2003 in the
newsgroup alt.certification.a-plus or
http://tinyurl.com/l3m9
"Power Surge" on 29 Sept 2003 in the newsgroup
alt.comp.hardware or
http://tinyurl.com/p1rk

Effective protection earths destructive common mode
transients which is why a less than 10 foot connection to
earth is essential. Ineffective protectors forget to mention
this earthing.

Its called 'shunt' mode protection. For example, lightning
has traveled miles through non-conductive air to obtain earth
ground through your electronics. Is that little 'series' mode
protector going to stop what miles of air could not? Of
course not. The Surgex recommendation has merit. But they
quietly forget to mention a wire that bypasses Surgex to carry
a destructive surge into your equipment. Even for Surgex to
be effective, a destructive transient must be earthed before
entering a building. What is the most critical component of
any protection system? Single point earth ground.

Far less expensive, more effective, and even required for
the Surgex to be effective is 'whole house' protector. The
most critical protection component being earth ground - which
Surgex forgets to mention to sell their products. Details in
those above previous discussions.

Surgex (Zerosurge and Brickwall and others) provides an
additional advantage. A low pass filter meaning that is will
also filter noise. But then properly designed electronics
already has this filtering internal. Internal noise
protection that is dependent on another ground - a single
point ground shared by components. Notice that not all
grounds are same - even if they are interconnected.

Two different types of transients must be addressed -
differential mode and common mode. The latter being the
typically destructive type that must be earthed before
entering the building. Without proper earthing and 'whole
house' protector, the destructive common mode transient can
simply take that bypass wire through Surgex into electronics.
Surgex is good additional protection after the more important
'whole house' protector and critically essential earth ground
is installed. Read those previous discussions.
Post by Steven Shelikoff
I was wrong, the Furmans are UL certified. They just don't claim it
in the literature. But it's on the UL website.
One thing though, UL does consider the performance parameters as
safety related for surge supressors. It's a lot more than just
finger in the socket or burst into flames. There's a lot of info
on the web about it.
http://www.currenttechnology.com/paper_8.htm
...
Thanks for the info on surgex. They look really nice. But you're
right, they are a lot more money than I wanted to spend. You pays
your money and takes your chances. The extra money for the surgex
buys you that little area of protection greater than the ones I
listed up to where the surgex itself fails. For me, I'll take the
chance that the "normal" ones like the Furmans and the ETAs will
be good enough.
Steve
Steven Shelikoff
2003-12-26 03:36:38 UTC
Permalink
On Thu, 25 Dec 2003 20:31:20 -0500, w_tom <***@hotmail.com> wrote:
[useful info snipped]
Post by w_tom
Effective protection earths destructive common mode
transients which is why a less than 10 foot connection to
earth is essential. Ineffective protectors forget to mention
this earthing.
Its called 'shunt' mode protection. For example, lightning
has traveled miles through non-conductive air to obtain earth
ground through your electronics. Is that little 'series' mode
protector going to stop what miles of air could not? Of
course not. The Surgex recommendation has merit. But they
quietly forget to mention a wire that bypasses Surgex to carry
a destructive surge into your equipment. Even for Surgex to
be effective, a destructive transient must be earthed before
entering a building. What is the most critical component of
any protection system? Single point earth ground.
Far less expensive, more effective, and even required for
the Surgex to be effective is 'whole house' protector. The
most critical protection component being earth ground - which
Since this is for a traveling rack system and a whole house protector
isn't practical and an earth ground cannot be assured, what would you
recommend as the best (i.e., most cost effective:) way of protecting the
equipment? Are you saying that since a 10' path to ground isn't
possible that I should just go with an inexpensive surge protector since
even the best can't work properly?

Steve
w_tom
2003-12-29 08:04:30 UTC
Permalink
Surge protection is earth ground. There is no way around
that so fundamental fact. In your mobile situation, place
shunt mode protector components as close to earth ground and
as far from transistors as is possible. IOW put a largest
joule protector at the far end of power cord at wall
receptacle or in another outlet that is 1) on same phase, and
2) closest to earth ground. One receptacle might be attached
to the main breaker box.

Of course, let's keep this all in perspective. Destructive
transients occur typically once every eight years; variance
determined by local conditions such as geology.

If earth ground does not exist, then nothing will provide
effective protection. Furthermore, that building has a
serious human safety problem. And if the best path to earth
ground is through your equipment, then the destructive
transient will pass through Surgex to obtain that earth
ground, destructively, via your electronics. Earthing is
fundamental to protection.

The Surgex is supplementary protection - after a shunt mode
protector has been connected as close to earth ground as is
practical. If no earth ground, then no 'miracle' device will
provide effective protection. It's really that simple. No
surge protector stops, blocks, or absorbs destructive
transients. However what is your risk considering the
frequency of surges; adjusted for local conditions? And do
you need the additional noise filtering that a Surgex would
also provide?
Post by Steven Shelikoff
Since this is for a traveling rack system and a whole house protector
isn't practical and an earth ground cannot be assured, what would you
recommend as the best (i.e., most cost effective:) way of protecting
the equipment? Are you saying that since a 10' path to ground isn't
possible that I should just go with an inexpensive surge protector
since even the best can't work properly?
Steve
Chris Hornbeck
2003-12-29 15:28:21 UTC
Permalink
Post by w_tom
Surge protection is earth ground. There is no way around
that so fundamental fact. In your mobile situation, place
shunt mode protector components as close to earth ground and
as far from transistors as is possible.
You may want to rethink this.

Chris Hornbeck
"Somebody spoke and I went into a dream"
w_tom
2003-12-30 01:30:46 UTC
Permalink
What part of that 50+ year old technology did you not
understand? Posted here was demonstrated effective annually in
millions of locations throughout the world for generations -
including your own home town. Which part did you not
understand?
Post by Chris Hornbeck
Post by w_tom
Surge protection is earth ground. There is no way around
that so fundamental fact. In your mobile situation, place
shunt mode protector components as close to earth ground and
as far from transistors as is possible.
You may want to rethink this.
Chris Hornbeck
2003-12-30 01:42:52 UTC
Permalink
Post by w_tom
What part of that 50+ year old technology did you not
understand? Posted here was demonstrated effective annually in
millions of locations throughout the world for generations -
including your own home town. Which part did you not
understand?
Well, the part about the earth ground contributing to the
protection of semiconductors some significant distance away.

I'm merely suggesting that you rethink your model. No need
to get upset.

Chris Hornbeck
w_tom
2003-12-30 02:23:35 UTC
Permalink
Nothing much to think about. The principles are well proven
even in pre WWII research papers.

View your telco switching station. Notice wires go
underground before entering the building. Why? Telephone
switching stations cannot afford failure. So all incoming
wires are best earthed typically 50 meters before they get to
the computer. For superior protection, the wire connects
short to earth and 50 meters away (yes that is about 150 feet)
from transistors. That 50 meters distance provides additional
protection for transistors. If protectors were adjacent to
transistors, then protection would be compromised. (Plug-in
protectors would have you not know this).

Nothing should imply 'upset'. You did not understand the
concept and left nothing posted upon which to clarify the
confusion. Shunt mode protectors adjacent to transitorized
appliances can even contribute to transistor damage.
Effective protection is short to central earth ground and
distant from protected transistors (50 meters in the telco
switching station example). That wire distance then becomes
another component of the protection system.
Post by Chris Hornbeck
Post by w_tom
What part of that 50+ year old technology did you not
understand? Posted here was demonstrated effective annually in
millions of locations throughout the world for generations -
including your own home town. Which part did you not
understand?
Well, the part about the earth ground contributing to the
protection of semiconductors some significant distance away.
I'm merely suggesting that you rethink your model. No need
to get upset.
Chris Hornbeck
Chris Hornbeck
2003-12-30 03:46:07 UTC
Permalink
Post by w_tom
That 50 meters distance provides additional
protection for transistors. If protectors were adjacent to
transistors, then protection would be compromised. (Plug-in
protectors would have you not know this).
Yabut, in a normal installation wouldn't this 50 meters
(or whatever) be unburied, and thus a large antenna?
Post by w_tom
Shunt mode protectors adjacent to transitorized
appliances can even contribute to transistor damage.
Again, you've lost me.
Post by w_tom
Effective protection is short to central earth ground and
distant from protected transistors (50 meters in the telco
switching station example). That wire distance then becomes
another component of the protection system.
As an inductor, its effect is mixed and system dependent.
But as an antenna, I can't see *any* upside.

Perhaps we differ mainly in what we consider to be the
greater (or perhaps the more common) threat. My experience
has been that for modern electronics the greatest threat
comes via EMP. Direct conduction strikes are statistically
rarer and of course bigger.

Chris Hornbeck
w_tom
2003-12-31 06:55:39 UTC
Permalink
It is a myth - antenna effect of those 50 meters will put
massive transients on that wire. This so called 'induced
surge' is really nothing more than noise. Noise easily made
irrelevant by protection built inside all electronics.

Another would have us believe half truths. For example,
10,000 volts induced by a nearby lightning strike. Now to
expose his missing facts by using a long wire antenna. Yes,
on the order of two thousand volts may appear on that long
wire antenna ... if antenna is not loaded. And so we put an
NE-2 neon glow lamp between that antenna and earth ground.
That thousands of volts drops to single digits because
milliamps (look at how low the current is) through that NE-2
load makes the transient voltage completely irrelevant and
almost zero.

BTW, surge damage is defined by the current - not voltage.
Voltage only becomes destructive when surge current is high
enough to create that voltage. But current from an EM field
on that 50 meter wire is so small as to be considered noise.

IEEE papers discuss induced transients on interior building
wires. Not from nearby lightning strikes. Induced transients
are a concern due to 'direct' strikes (to building or incoming
wires). Induced transient occurs when an earthing wire is
bundled with other wires. Current on that earthing wire
induces a transient on other bundled wires. Therefore
properly installed system always separate the earthing wire
from all other wires - to avoid induced transients. Was an
induced transient misrepresented as EM field generated EMP?
There is no 10,000 volts on that 50 meter connection. There
is no destructive surge on that 50 meters between surge
protector and computer.

Let's assume a nearby strike could generate thousand of
volts on interior building wires. Then same EM field must
damage the low voltage RF amplifier transistors in every
nearby automobile radio (powered on or off). Then every
nearby TV receiver connected to an aerial would be damaged.
Then every TV and cable modem connected to long CATV cables
would be damaged. Why are TVs, portable and auto radios not
routinely destroyed by nearby strikes? Because a massive
voltage transient advocated by myths does not really exist.

Does the transistor side of a 50 meter cable also need a
surge protector? Why? Anything that a plug-in protector will
provide is already inside that equipment. Electronic
equipment has sufficient internal protection. But that
'manufacturer provided' protection may be overwhelmed if a
transient is not earthed 1) at service entrance and 2) distant
from the transistor.

BTW, a reason for promoting myths about massive surges on
that 50 meter wire is that, well, what is the alternative?
Otherwise we would stop buying those useless plug-in
protectors.

Ballpark numbers demonstrate no 'surge' on that 50 meter
wire. Perform the experiment. Hang a 50 meter wire antenna
with one end attached to earth via an NE-2 glow lamp. Then
notice how often that neon glow lamp is 'destroyed' by nearby
lightning strikes. At best, milliamps from EMP might cause
the NE-2 to glow in a dark room. EMP is that insignificant.
If induced transients cannot even destroy an NE-2 glow lamp,
then how will transients overwhelm protection already inside
electronic devices?

Please explain where your EMP induced surge is? Define it
in terms of common mode or differential mode current -
important parameters when discussing transients. Please
explain how many hundreds of volts with sufficient current can
be induced on an interior 50 meter wire while tens of volts
necessary to destroy RF transistors is not induced on TV or
portable radio? Please explain why decades of proven
protection designs are wrong?

A common mistake - many confuse a direct strike as a nearby
one. For example, too many don't even know an internal
computer modem connects hardwire to an AC electric wire.
Therefore modem must have been damaged by EM fields of a
nearby CG strike since that AC wire connection does not
exist. Or they think a CG strike to the nearby tree did not
also strike those incoming utility wires (lightning can
dance). Or they think a relay separates electronics from an
incoming utility wire. To a transient, the relay's wiper
connects directly to the relay coil as defined in specs by
breakdown voltage. Just three reasons why some might not
understand it was a direct strike - and then assume it must
have been EMP. If it was EMP, then every nearby portable AM
radio was destroyed.
Post by Chris Hornbeck
Post by w_tom
That 50 meters distance provides additional
protection for transistors. If protectors were adjacent to
transistors, then protection would be compromised. (Plug-in
protectors would have you not know this).
Yabut, in a normal installation wouldn't this 50 meters
(or whatever) be unburied, and thus a large antenna?
...
Perhaps we differ mainly in what we consider to be the
greater (or perhaps the more common) threat. My experience
has been that for modern electronics the greatest threat
comes via EMP. Direct conduction strikes are statistically
rarer and of course bigger.
Chris Hornbeck
Scott Dorsey
2003-12-31 15:02:29 UTC
Permalink
Post by w_tom
Another would have us believe half truths. For example,
10,000 volts induced by a nearby lightning strike. Now to
expose his missing facts by using a long wire antenna. Yes,
on the order of two thousand volts may appear on that long
wire antenna ... if antenna is not loaded. And so we put an
NE-2 neon glow lamp between that antenna and earth ground.
That thousands of volts drops to single digits because
milliamps (look at how low the current is) through that NE-2
load makes the transient voltage completely irrelevant and
almost zero.
Dunno about that. I had an 80M dipole that I was disconnecting during
a storm, when a lightning strike hit some distance away. Big flash, knocked
me over, blew off the tip of the UHF connector as it arced from one connector
to the other. (The old Collins radio on the other end was not damaged).
Anything that can burn the tip off a UHF connector is not a few milliamps.

The strike was at least far enough away that I could tell a good difference in
time between the thunder and lightning.

That said, if I run an NE2 between my antenna and ground, it will flash like
mad during the thunderstorm, and it does indeed safely carry most of the
transients to ground without any problem. And if I put a xenon lamp between
the antenna and ground, it won't flash visibly much because there isn't
enough current to light it, even though there's more than enough voltage to
get it to fire. An event like the one above is not a common thing, and that
most certainly would fire off the xenon tube, but I've never seen one when
I was looking for it.
Post by w_tom
BTW, surge damage is defined by the current - not voltage.
Voltage only becomes destructive when surge current is high
enough to create that voltage. But current from an EM field
on that 50 meter wire is so small as to be considered noise.
Most of the time, yeah. And I would agree that designing power supplies
properly to deal with the issue would be a more intelligent thing than
putting surge suppressors at every outlet.
Post by w_tom
IEEE papers discuss induced transients on interior building
wires. Not from nearby lightning strikes. Induced transients
are a concern due to 'direct' strikes (to building or incoming
wires). Induced transient occurs when an earthing wire is
bundled with other wires. Current on that earthing wire
induces a transient on other bundled wires. Therefore
properly installed system always separate the earthing wire
from all other wires - to avoid induced transients. Was an
induced transient misrepresented as EM field generated EMP?
There is no 10,000 volts on that 50 meter connection. There
is no destructive surge on that 50 meters between surge
protector and computer.
If it is direct, how can it be induced?
Post by w_tom
Does the transistor side of a 50 meter cable also need a
surge protector? Why? Anything that a plug-in protector will
provide is already inside that equipment. Electronic
equipment has sufficient internal protection. But that
'manufacturer provided' protection may be overwhelmed if a
transient is not earthed 1) at service entrance and 2) distant
from the transistor.
Sadly not. If the equipment WERE designed that way, we wouldn't have
anywhere near the problem that we do. That's my big worry.
Post by w_tom
BTW, a reason for promoting myths about massive surges on
that 50 meter wire is that, well, what is the alternative?
Otherwise we would stop buying those useless plug-in
protectors.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
w_tom
2003-12-31 23:17:36 UTC
Permalink
Few milliamps will shock the human body. Something like
five milliamps across the heart at a right time can kill.
Touch a 120 or 240 volt wire when skin is dry. It does not
kill since body (dry skin) is on the order of 1 megohm
resistance meaning it is milliamps of current. Still, it too
hurts.

So how much was that current from an 80m dipole? Same as
from a 240 volt shock? Then it too hurt but was only enough
current to light an NE-2. 240 volts divided by 1 megohm is
not much current - and still that hurts inside the body. The
amount of pain does not define a destructive transient.

In the meantime, I don't see anything that proves a dipole
strike was induced by EM fields. For example, some campers
were sleeping around a tree when struck. Those sleeping
perpendicular to the tree were not harmed. Those sleeping
pointed to the tree suffered shocks. Electricity left ground,
travel length of sleeping camper, then returned to earth.
Electricity could have left ground, passed through dipole,
through your body, then back to earth via your feet. You and
campers suffered from being part of the ground circuit. No
EMP from a nearby strike. Just another example of how
lightning can pass through a body. Like those harmed campers,
you and your dipole were a better path for lightning that was
traveling through earth.

As for a burned UHF tip - that and in the sky is where the
energy dissipation happens. As Martin A Uman says in "All
Most of the energy available to the lightning is converted
along the lightning channel to thunder, heat, light, and radio
waves, leaving only a fraction available at the channel base
for immediate use or storage.
A burned UHF tip does not mean massive surge to the
connected electronics. An change of media (from plasma to
metal) would be a point of greater energy dissipation. Energy
is not dissipated equally everywhere in that transient path.
Therefore the amount of energy you experienced may be quite
different from energy on that UHF tip.

This much we know from research AND it is why a 50 meter
separation is so desirable in that telephone switching
station. There is no massive surge induced on that 50 meter
wire by a nearby strike. And certainly nothing that would
overwhelm protection already existing in that computer.


Induced surge: take, for example, a direct lightning strike
to building that travels through building into earth ground.
That interior earthing wire carries the direct strike. Other
signal and power wires are bundled with that grounding wire.
Those other wires suffer induced transient from being bundled
(electromagnetically coupled) with that earthing wire. Those
other wires suffer induced transients. Earthing wires must be
dedicated and separate from other wires to avoid induced
transients.

Now let's take a plug-in surge protector that is suppose to
earth the transient down a Romex safety ground wire. Romex
ground wire also is bundled with many other non grounding
wires (obviously). By attempting to earth a surge on that
Romex ground wire, the plug-in protector has now induced
surges on other circuits. Just another reason why plug-in
shunt mode protector is not effective protection.

Surge protector must 1) shunt a surge before it enters a
building, 2) connect less than 10 feet to central earth
ground, and 3) have an earthing wire routed separate from
other non grounding wires. Three more things a plug-in
protector cannot accomplish. Number 3 is another example of
induced transients because a dedicated ground wire is
electromagnetically coupled to (bundled with) other wires.


What equipment does not already have sufficient internal
protection? Computer modems already contain galvanic
isolation (the DAA circuit) to phone line. Typically 2000
volts protection. Network Interface Cards also have galvanic
isolation. That too would be maybe 2000 volt or better
protection. Your telephone, if I recall FCC part 68, must
withstand something like 1500 volts. Again plenty of internal
protection. In each case, protection that is sufficient IF a
transient is earthed before it can enter the building. ATX
power supplies, as was defacto standard even 30 years ago,
were good for something approaching 2000 volts common mode.
The CBEMA required all electronic equipment to withstand
transients of 600 volts without damage - the most minimal
standard I could find.

Where is this equipment that does not have internal
protection? Yes, equipment must have good internal
protection. Instead the sentence should have read, "SINCE the
equipment IS designed that way..."

It is not "... designing power supplies properly to deal
with the issue would be a more intelligent thing".
It is "... power supplies are properly designed to deal with
the issue".

Power supplies already have sufficient internal protection.
Even Intel ATX power supply specs require internal protection
that has long been defacto standard.

But again, all this existing protection works IF a
destructive transient is earthed before entering the
building. Also what those Franklin air terminals (lightning
rods) are for. Also why the utility pole transformer is
earthed. Also why a building electrician should install
properly earthed 'whole house' protectors - so that the last
remaining incoming path (utility wires) cannot carry a direct
strike into the building.

The most common source of destructive transients? The one
utility line that is highest on pole, most likely struck, and
rarely has any 'whole house' type protection - AC electric.
If only someone had put the last piece into the puzzle before
lightning struck.... Worse still, the effective solution
costs even less than ineffective plug-in protectors!
Dunno about that. I had an 80M dipole that I was disconnecting
during a storm, when a lightning strike hit some distance away.
Big flash, knocked me over, blew off the tip of the UHF connector
as it arced from one connector to the other. (The old Collins
radio on the other end was not damaged). Anything that can burn
the tip off a UHF connector is not a few milliamps.
The strike was at least far enough away that I could tell a good
difference in time between the thunder and lightning.
That said, if I run an NE2 between my antenna and ground, it will
flash like mad during the thunderstorm, and it does indeed safely
carry most of the transients to ground without any problem. And
if I put a xenon lamp between the antenna and ground, it won't
flash visibly much because there isn't enough current to light it,
even though there's more than enough voltage to get it to fire.
An event like the one above is not a common thing, and that
most certainly would fire off the xenon tube, but I've never seen
one when I was looking for it.
...
Most of the time, yeah. And I would agree that designing power
supplies properly to deal with the issue would be a more
intelligent thing than putting surge suppressors at every outlet.
Post by w_tom
IEEE papers discuss induced transients on interior building
wires. Not from nearby lightning strikes. Induced transients
are a concern due to 'direct' strikes (to building or incoming
wires). Induced transient occurs when an earthing wire is
bundled with other wires. Current on that earthing wire
induces a transient on other bundled wires. ...
If it is direct, how can it be induced?
Post by w_tom
Does the transistor side of a 50 meter cable also need a
surge protector? Why? Anything that a plug-in protector
will provide is already inside that equipment. Electronic
equipment has sufficient internal protection. ...
Sadly not. If the equipment WERE designed that way, we wouldn't have
anywhere near the problem that we do. That's my big worry.
...
Richard Freeman
2004-01-01 00:11:47 UTC
Permalink
Post by w_tom
Few milliamps will shock the human body. Something like
five milliamps across the heart at a right time can kill.
Touch a 120 or 240 volt wire when skin is dry. It does not
kill since body (dry skin) is on the order of 1 megohm
resistance meaning it is milliamps of current. Still, it too
hurts.
And is enough to damage electronics
Post by w_tom
So how much was that current from an 80m dipole? Same as
from a 240 volt shock? Then it too hurt but was only enough
current to light an NE-2. 240 volts divided by 1 megohm is
not much current - and still that hurts inside the body. The
amount of pain does not define a destructive transient.
In the meantime, I don't see anything that proves a dipole
strike was induced by EM fields.
That is because you do not understand the basic physics involved
Post by w_tom
For example, some campers
were sleeping around a tree when struck. Those sleeping
perpendicular to the tree were not harmed. Those sleeping
pointed to the tree suffered shocks. Electricity left ground,
travel length of sleeping camper, then returned to earth.
Electricity could have left ground, passed through dipole,
through your body, then back to earth via your feet. You and
campers suffered from being part of the ground circuit. No
EMP from a nearby strike. Just another example of how
lightning can pass through a body. Like those harmed campers,
you and your dipole were a better path for lightning that was
traveling through earth.
w_tom is confusing EPR/GPR here with EMP and making a real pigs breakfast of
it Scotts example had nothing to do with EPR
Post by w_tom
As for a burned UHF tip - that and in the sky is where the
energy dissipation happens.
and any relatively high impedance points in the Circuit -
This as any first year physics student would know is because power = current
times voltage
Voltage = Current time Resistance

therefore assuming the current is the constant (Lightning for the purpose of
analysis is effectively a constant current source)
then power is dissipated wherever the resistance is high

As Martin A Uman says in "All
Post by w_tom
About Lightning"
A well written book I suggest w_tom takes the time to understand - Martin
has kept it nice and simple it should be well within w_toms capability to
understand it.
Post by w_tom
Most of the energy available to the lightning is converted
along the lightning channel to thunder, heat, light, and radio
waves, leaving only a fraction available at the channel base
for immediate use or storage.
A burned UHF tip does not mean massive surge to the
connected electronics. An change of media (from plasma to
metal) would be a point of greater energy dissipation. Energy
is not dissipated equally everywhere in that transient path.
Therefore the amount of energy you experienced may be quite
different from energy on that UHF tip.
current however is the same along the whole path and sufficent current to
vaporise metal will be sufficent to damage delicate electronics inside the
equipment.
Post by w_tom
This much we know from research AND it is why a 50 meter
separation is so desirable in that telephone switching
station. There is no massive surge induced on that 50 meter
wire by a nearby strike. And certainly nothing that would
overwhelm protection already existing in that computer.
yet it still does get damaged - rarely I admit but it does happen

-----snipped crap I couldnt be bothered answering AGAIN-
Post by w_tom
What equipment does not already have sufficient internal
protection? Computer modems already contain galvanic
isolation (the DAA circuit) to phone line. Typically 2000
volts protection. Network Interface Cards also have galvanic
isolation. That too would be maybe 2000 volt or better
protection. Your telephone, if I recall FCC part 68, must
withstand something like 1500 volts. Again plenty of internal
protection. In each case, protection that is sufficient IF a
transient is earthed before it can enter the building. ATX
power supplies, as was defacto standard even 30 years ago,
were good for something approaching 2000 volts common mode.
The CBEMA required all electronic equipment to withstand
transients of 600 volts without damage - the most minimal
standard I could find.
NB galvanic Isolation = effectively a high resistance point in the circuit
this means that when this isolation does breakdown (and despite what w_tom
says it will break down in a near or direct strike) this is where the power
is dissipated this is why modems after Lightning strikes ususally show signs
of burning around the Line interface. Telephones are usually floating and
hence ride out Lightning strikes.
Post by w_tom
Where is this equipment that does not have internal
protection? Yes, equipment must have good internal
protection. Instead the sentence should have read, "SINCE the
equipment IS designed that way..."
Equipment is not designed to protect against a near or direct Lightning
strike as :
This is difficult (almost impossible) to do
Near/Direct Strikes are not a common event
Post by w_tom
It is not "... designing power supplies properly to deal
with the issue would be a more intelligent thing".
It is "... power supplies are properly designed to deal with
the issue".
Power supplies already have sufficient internal protection.
Even Intel ATX power supply specs require internal protection
that has long been defacto standard.
But again, all this existing protection works IF a
destructive transient is earthed before entering the
building. Also what those Franklin air terminals (lightning
rods) are for. Also why the utility pole transformer is
earthed. Also why a building electrician should install
properly earthed 'whole house' protectors - so that the last
remaining incoming path (utility wires) cannot carry a direct
strike into the building.
The most common source of destructive transients?
here w_tom stands on his head and says the sky is green
Post by w_tom
The one
utility line that is highest on pole, most likely struck, and
rarely has any 'whole house' type protection - AC electric.
well actually wrong AC power distribution uses low impedance wiring and the
MEN system provides the best Earthing system that is availabel AC power
typically rides out direct strkes fairly well - Lightning damage is possible
via AC electric but is extremely rare mainly because of the superb earthing
provided by the MEN system.

In reality the vast majority of lightning damage can be traced to Lightning
entering via Phone lines (by far the single most common source of Lightning
damage and in this I have included cable modems, data lines etc) Aerials and
building wiring.
Post by w_tom
If only someone had put the last piece into the puzzle before
lightning struck.... Worse still, the effective solution
costs even less than ineffective plug-in protectors!
If only people were more honest about Lightning Protection - namely that it
really is a line of last resort at best and that the only 100% effective
protection is disconnecting when Lightning comes. and did not speak such
utter crap
Post by w_tom
Scott Dorsey who knows infinetly more about Lightning
than w_tom - sorry that is hardly a compliment ;-)
Regards
Richard freeman
Scott Dorsey
2004-01-01 15:01:00 UTC
Permalink
Post by w_tom
Few milliamps will shock the human body. Something like
five milliamps across the heart at a right time can kill.
Touch a 120 or 240 volt wire when skin is dry. It does not
kill since body (dry skin) is on the order of 1 megohm
resistance meaning it is milliamps of current. Still, it too
hurts.
Yup.
Post by w_tom
So how much was that current from an 80m dipole? Same as
from a 240 volt shock? Then it too hurt but was only enough
current to light an NE-2. 240 volts divided by 1 megohm is
not much current - and still that hurts inside the body. The
amount of pain does not define a destructive transient.
Probably a lot more than from a 240 volt shock. I wasn't even in
the circuit and I was knocked over just from the radiated stuff
from holding one side of the ground.

Remember, we're talking about stuff with a very fast risetime
here. You can get an incredible shock without being injured much
because it travels on the surface of the conductor. And you don't
have to complete a circuit for it to travel over you.

This is why we do things like make lightning loops in coax feedlines;
the risetime is so fast that a single loop will act like enough of
a choke to encourage the lightning to arc from the feedline shield to
ground rather than through the gear at the other end of the feedline.
Post by w_tom
In the meantime, I don't see anything that proves a dipole
strike was induced by EM fields. For example, some campers
were sleeping around a tree when struck. Those sleeping
perpendicular to the tree were not harmed. Those sleeping
pointed to the tree suffered shocks. Electricity left ground,
travel length of sleeping camper, then returned to earth.
Electricity could have left ground, passed through dipole,
through your body, then back to earth via your feet. You and
campers suffered from being part of the ground circuit. No
EMP from a nearby strike. Just another example of how
lightning can pass through a body. Like those harmed campers,
you and your dipole were a better path for lightning that was
traveling through earth.
It didn't go through me. It went from the shield of the cable to
the nearby grounded UHF connector, jumped a couple inches, and
grounded itself through the transmitter grounding system (which
is very direct and short because it's specifically intended to sink
RF).

I just happened to have been holding the insulated part of the coax
and got a tiny current induced in me in the process, but the exciting
part of it, and the part that indicates the current involved, was the
arc.
Post by w_tom
As for a burned UHF tip - that and in the sky is where the
energy dissipation happens. As Martin A Uman says in "All
Most of the energy available to the lightning is converted
along the lightning channel to thunder, heat, light, and radio
waves, leaving only a fraction available at the channel base
for immediate use or storage.
A burned UHF tip does not mean massive surge to the
connected electronics. An change of media (from plasma to
metal) would be a point of greater energy dissipation. Energy
is not dissipated equally everywhere in that transient path.
Therefore the amount of energy you experienced may be quite
different from energy on that UHF tip.
No, there was in fact no real serious surge to the connected electronics,
in part because there are spark gaps on the final tubes for precisely
this sort of thing, in addition to larger spark gaps at the antenna
feedline where it comes into the house.

The burned connector tip, though, indicates the amount of current that
was passing from the feedline through the grounding system.
Post by w_tom
This much we know from research AND it is why a 50 meter
separation is so desirable in that telephone switching
station. There is no massive surge induced on that 50 meter
wire by a nearby strike. And certainly nothing that would
overwhelm protection already existing in that computer.
And are there any chokes on this 50 meter line? An 88mH repeat coil
will go a long way toward killing fast risetime stuff. Loops and rails?
Post by w_tom
Induced surge: take, for example, a direct lightning strike
to building that travels through building into earth ground.
That interior earthing wire carries the direct strike. Other
signal and power wires are bundled with that grounding wire.
Those other wires suffer induced transient from being bundled
(electromagnetically coupled) with that earthing wire. Those
other wires suffer induced transients. Earthing wires must be
dedicated and separate from other wires to avoid induced
transients.
I can buy this, but this is the result of the two grounding systems
(interior and exterior) being at different potentials. Remember we
are talking about RF here... lightning does not behave like DC at all.
Post by w_tom
Now let's take a plug-in surge protector that is suppose to
earth the transient down a Romex safety ground wire. Romex
ground wire also is bundled with many other non grounding
wires (obviously). By attempting to earth a surge on that
Romex ground wire, the plug-in protector has now induced
surges on other circuits. Just another reason why plug-in
shunt mode protector is not effective protection.
As long as it induces the SAME surge on both power leads that exists
on the ground, it's fine. As long as everything everywhere is at the
same potential, everything is great. When one thing is at a different
potential (either because there is an external connection, or because
the case of the equipment is radiating RF and is therefore at a lower
potential than the ground line inside), it's bad.
Post by w_tom
Surge protector must 1) shunt a surge before it enters a
building, 2) connect less than 10 feet to central earth
ground, and 3) have an earthing wire routed separate from
other non grounding wires. Three more things a plug-in
protector cannot accomplish. Number 3 is another example of
induced transients because a dedicated ground wire is
electromagnetically coupled to (bundled with) other wires.
Having a system that does this on power lines is essential. But it
does not mean that additional protection isn't good also. And it does
not mean that protection on signal lines isn't also important.
Post by w_tom
What equipment does not already have sufficient internal
protection? Computer modems already contain galvanic
isolation (the DAA circuit) to phone line. Typically 2000
volts protection. Network Interface Cards also have galvanic
isolation. That too would be maybe 2000 volt or better
protection. Your telephone, if I recall FCC part 68, must
withstand something like 1500 volts. Again plenty of internal
protection. In each case, protection that is sufficient IF a
transient is earthed before it can enter the building. ATX
power supplies, as was defacto standard even 30 years ago,
were good for something approaching 2000 volts common mode.
The CBEMA required all electronic equipment to withstand
transients of 600 volts without damage - the most minimal
standard I could find.
Right. The thing is, a typical service entry panel won't pass anything
higher than 6 KV because that's the point at which it will arc over
to ground internally. We can put big arrestors on the service entry to
clamp things down to 600V or so (basically big MOVs made with powdered
zinc in tubes). But this is RF... and clamping at one point in the
line may not help if it happens to be a node.
Post by w_tom
Where is this equipment that does not have internal
protection? Yes, equipment must have good internal
protection. Instead the sentence should have read, "SINCE the
equipment IS designed that way..."
Wall warts will fail if you look at them. Plenty of gear out there has
the pin 1 problem, which is a nightmare from many different RF pickup
perspectives. Until this goes away we have to deal with it.
Post by w_tom
It is not "... designing power supplies properly to deal
with the issue would be a more intelligent thing".
It is "... power supplies are properly designed to deal with
the issue".
Power supplies already have sufficient internal protection.
Even Intel ATX power supply specs require internal protection
that has long been defacto standard.
Why are there so many ADATs with blown supply rectifiers, then?
Why do wall warts die like mad with even slight line variations?
Computer power supplies are the least of your worries.
Post by w_tom
But again, all this existing protection works IF a
destructive transient is earthed before entering the
building. Also what those Franklin air terminals (lightning
rods) are for. Also why the utility pole transformer is
earthed. Also why a building electrician should install
properly earthed 'whole house' protectors - so that the last
remaining incoming path (utility wires) cannot carry a direct
strike into the building.
This is true, but we're still talking about RF here, and RF can get
induced in fairly large levels in nearby conductors, even as it is
earthed to ground.
Post by w_tom
The most common source of destructive transients? The one
utility line that is highest on pole, most likely struck, and
rarely has any 'whole house' type protection - AC electric.
If only someone had put the last piece into the puzzle before
lightning struck.... Worse still, the effective solution
costs even less than ineffective plug-in protectors!
I think we're assuming for this argument that everyone is reasonably
protected at the panel.... it would be foolish not to be and that would
pretty much invalidate any arguments. But protection at the panel is not
enough, and it won't be until the pin 1 problem goes away and power supplies
and audio grounding systems improve.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Richard Freeman
2004-01-02 23:41:47 UTC
Permalink
Post by Scott Dorsey
Post by w_tom
Few milliamps will shock the human body. Something like
five milliamps across the heart at a right time can kill.
Touch a 120 or 240 volt wire when skin is dry. It does not
kill since body (dry skin) is on the order of 1 megohm
resistance meaning it is milliamps of current. Still, it too
hurts.
Yup.
And still enough to damage electronics (Remember this thread started off as
a discussion on protecting Audio gear)
Post by Scott Dorsey
Post by w_tom
So how much was that current from an 80m dipole? Same as
from a 240 volt shock? Then it too hurt but was only enough
-------------- snipped for brevity--------------------------
Post by Scott Dorsey
No, there was in fact no real serious surge to the connected electronics,
in part because there are spark gaps on the final tubes for precisely
this sort of thing, in addition to larger spark gaps at the antenna
feedline where it comes into the house.
The burned connector tip, though, indicates the amount of current that
was passing from the feedline through the grounding system.
Post by w_tom
This much we know from research AND it is why a 50 meter
separation is so desirable in that telephone switching
station. There is no massive surge induced on that 50 meter
wire by a nearby strike. And certainly nothing that would
overwhelm protection already existing in that computer.
And are there any chokes on this 50 meter line? An 88mH repeat coil
will go a long way toward
Nope not usually in the last 50M into the Exchange (w_tom is the wrong
person to ask about things like this as with most subjects w_tom
pontificates about his ignorance on the subject is almost complete ) think
about it how well would say ADSL work with inductors on the phone line ? -
loading coils may be used on longer distance or Trunk cables but not
typically on local cables.
Post by Scott Dorsey
Post by w_tom
Induced surge: take, for example, a direct lightning strike
to building that travels through building into earth ground.
That interior earthing wire carries the direct strike. Other
signal and power wires are bundled with that grounding wire.
Those other wires suffer induced transient from being bundled
(electromagnetically coupled) with that earthing wire. Those
other wires suffer induced transients. Earthing wires must be
dedicated and separate from other wires to avoid induced
transients.
except in the case of a PA system in a building there is plenty of cabling
laid out to pick up EMP and hang on a minute didnt w_tom just say that EMP
was not induced into other cables ? looks like he is contradicting himself
here
Post by Scott Dorsey
I can buy this, but this is the result of the two grounding systems
(interior and exterior) being at different potentials. Remember we
are talking about RF here... lightning does not behave like DC at all.
But w_tom dispute the exsistence of EPR
Post by Scott Dorsey
Post by w_tom
Now let's take a plug-in surge protector that is suppose to
earth the transient down a Romex safety ground wire. Romex
ground wire also is bundled with many other non grounding
wires (obviously). By attempting to earth a surge on that
Romex ground wire, the plug-in protector has now induced
surges on other circuits. Just another reason why plug-in
shunt mode protector is not effective protection.
As long as it induces the SAME surge on both power leads that exists
on the ground, it's fine. As long as everything everywhere is at the
same potential, everything is great. When one thing is at a different
potential (either because there is an external connection, or because
the case of the equipment is radiating RF and is therefore at a lower
potential than the ground line inside), it's bad.
Plug in surge arrestors evidently dont earn any money for w_tom
Post by Scott Dorsey
Post by w_tom
Surge protector must 1) shunt a surge before it enters a
building, 2) connect less than 10 feet to central earth
ground, and 3) have an earthing wire routed separate from
other non grounding wires. Three more things a plug-in
protector cannot accomplish. Number 3 is another example of
induced transients because a dedicated ground wire is
electromagnetically coupled to (bundled with) other wires.
Having a system that does this on power lines is essential. But it
does not mean that additional protection isn't good also. And it does
not mean that protection on signal lines isn't also important.
Protection on other lines is equally essential as paths of Lightning causing
damage are (Listed in order) :

Phone/Data Lines
TV /Radio Aerials
Building Cabling/wiring from Direct or Near strike (inc EPR from
multiple Earth points)
AC Mains

So we see from basic analysis that Surge protection on AC mains alone
provides a tiny fraction of Lightning protection required to be effective.
Post by Scott Dorsey
Post by w_tom
What equipment does not already have sufficient internal
protection? Computer modems already contain galvanic
isolation (the DAA circuit) to phone line. Typically 2000
volts protection. Network Interface Cards also have galvanic
isolation. That too would be maybe 2000 volt or better
protection. Your telephone, if I recall FCC part 68, must
withstand something like 1500 volts. Again plenty of internal
protection. In each case, protection that is sufficient IF a
transient is earthed before it can enter the building. ATX
power supplies, as was defacto standard even 30 years ago,
were good for something approaching 2000 volts common mode.
The CBEMA required all electronic equipment to withstand
transients of 600 volts without damage - the most minimal
standard I could find.
Right. The thing is, a typical service entry panel won't pass anything
higher than 6 KV because that's the point at which it will arc over
to ground internally. We can put big arrestors on the service entry to
clamp things down to 600V or so (basically big MOVs made with powdered
zinc in tubes). But this is RF... and clamping at one point in the
line may not help if it happens to be a node.
Post by w_tom
Where is this equipment that does not have internal
protection? Yes, equipment must have good internal
protection. Instead the sentence should have read, "SINCE the
equipment IS designed that way..."
Wall warts will fail if you look at them. Plenty of gear out there has
the pin 1 problem, which is a nightmare from many different RF pickup
perspectives. Until this goes away we have to deal with it.
Post by w_tom
It is not "... designing power supplies properly to deal
with the issue would be a more intelligent thing".
It is "... power supplies are properly designed to deal with
the issue".
Power supplies already have sufficient internal protection.
Even Intel ATX power supply specs require internal protection
that has long been defacto standard.
Why are there so many ADATs with blown supply rectifiers, then?
Why do wall warts die like mad with even slight line variations?
Computer power supplies are the least of your worries.
Post by w_tom
But again, all this existing protection works IF a
destructive transient is earthed before entering the
building. Also what those Franklin air terminals (lightning
rods) are for. Also why the utility pole transformer is
earthed. Also why a building electrician should install
properly earthed 'whole house' protectors - so that the last
remaining incoming path (utility wires) cannot carry a direct
strike into the building.
This is true, but we're still talking about RF here, and RF can get
induced in fairly large levels in nearby conductors, even as it is
earthed to ground.
Post by w_tom
The most common source of destructive transients? The one
utility line that is highest on pole, most likely struck, and
Umm that would be the Earth wire strung along poles to protect against this
very event ...
Actually this is just a blatent lie told by w_tom by far the most common
path of Lightning damage is via Phone and Data Lines a small fact that shows
w_toms advice on Lightning protection up for the Lies they are - In order to
explain away the damage to modems and Faxes which does not usually affect
any other item in the House w_tom has come up with a real fruitcake (and
completely wrong) theory - that is that there is a direct connection between
the Electronics in a modern modem and AC mains. It is a shame that this
theory is proven incorrect (like many of his other Fantasies) by the common
use of wall warts which provide double insulation on most modern modems
Post by Scott Dorsey
Post by w_tom
rarely has any 'whole house' type protection - AC electric.
If only someone had put the last piece into the puzzle before
lightning struck.... Worse still, the effective solution
costs even less than ineffective plug-in protectors!
I think we're assuming for this argument that everyone is reasonably
protected at the panel.... it would be foolish not to be and that would
pretty much invalidate any arguments. But protection at the panel is not
enough, and it won't be until the pin 1 problem goes away and power supplies
and audio grounding systems improve.
the MEN system provides pretty effective protection against Lightning - this
is largely born out by the very localised patterns of damage around
Lightning strikes - usually confined to well within 100M of a Lightning
strike typically within 20 - 50 M with power distribution areas (in my area)
going to 300M + if w_toms fantasies were correct then every ground strike
would wreak untold amounts of damage

Telco cable plant on the other hand is typically unearthed and I have seen
Lightning damage on equipment 4Kms away from a Lightning strike..... But I
digress Audio Systems like phone lines are often unearthed or have single
point earthing which has its good and bad points but even many mixing desks
(including a Mackie SR24-4 I recently serviced after a near strike) have 10
ohm resistors between pin1 on the Mic input connectors and earth and means
that the mic lines often float sufficently to pick up enough current to
cause damage in a near or direct strike.
No lies told by w_tom unforunately change this fact that Lightning damage
does occour to PA systems during Lightning strikes and the path of damage is
not usually via AC mains.

Taking advice from w_tom on Lightning protection is a bit like taking advice
on colours from blind freddy.

Regards
Richard Freeman

Richard Freeman
2003-12-31 23:30:53 UTC
Permalink
Post by w_tom
It is a myth - antenna effect of those 50 meters will put
massive transients on that wire. This so called 'induced
surge' is really nothing more than noise. Noise easily made
irrelevant by protection built inside all electronics.
Another would have us believe half truths. For example,
10,000 volts induced by a nearby lightning strike.
10,000 Volts was a conservative figure and this is the EPR/GPR on a single
Earth stake during a lightning strike not EMP you see EPR is Spelled : E P
R and EMP is spelled E M P they are actually quite different even if they
start with the same letter.

Glad to see w_tom is reading my postings ( he might learn something one day
!) even if he does not have sufficient understanding of basic physics or
basic electricity to debate me head to head however like many of w_toms
statements he has chosen to deliberately lie about what that 10,000V was.
This is the reason he Top posts and snips the points he pretends to be
answering so that the casual reader cannot readily see that he is misquoting
the previous post and in many cases (like this one) telling outright lies
about what was said.
Post by w_tom
Now to expose his missing facts by using a long wire antenna.
not even Slightly relevant to the Situation stated which was a direct strike
and the EPR/GPR on an Earth stake.
Post by w_tom
Yes,
on the order of two thousand volts may appear on that long
wire antenna ... if antenna is not loaded.
and provided the antenna does not receive a near or direct strike
Post by w_tom
And so we put an
NE-2 neon glow lamp between that antenna and earth ground.
That thousands of volts drops to single digits because
milliamps (look at how low the current is) through that NE-2
load makes the transient voltage completely irrelevant and
almost zero.
however if that Antenna cops a near or direct strike the NE2 evaporates due
to the 100,s if not 1000s of amps flowing through it just like the MOV at :
http://www.nettally.com/saints/lightning.html
Post by w_tom
BTW, surge damage is defined by the current - not voltage.
Voltage only becomes destructive when surge current is high
enough to create that voltage.
Provide you are only dealing with bits of wire, introduce semiconductors
into the story and you have a whole new ball game including MOS devices that
can and are damaged by the static electricity on an un earthed person - Fact
Electronics manufacturing plants that observe correct antistatic procedure
experience a far far lower failure rate than those that don't and this is
dealing with currents and voltages that are minute.

And then their are output devices on power amplifiers where the EMP can
exceed the breakdown voltage and the Power supply then provides sufficent
current to kill the device properly.
Post by w_tom
But current from an EM field
on that 50 meter wire is so small as to be considered noise.
Says Someone who has not needed to clear up the damage after a near or
Direct strike anywhere near as often as I have
Post by w_tom
IEEE papers discuss induced transients on interior building
wires. Not from nearby lightning strikes. Induced transients
are a concern due to 'direct' strikes (to building or incoming
wires). Induced transient occurs when an earthing wire is
bundled with other wires. Current on that earthing wire
induces a transient on other bundled wires. Therefore
properly installed system always separate the earthing wire
from all other wires - to avoid induced transients. Was an
induced transient misrepresented as EM field generated EMP?
There is no 10,000 volts on that 50 meter connection. There
is no destructive surge on that 50 meters between surge
protector and computer.
I have seen damage on equipment connected together by a serial interface
around 10- 15M long after a Near (not even a direct) strike ( the strike
occurred around 20M away
Post by w_tom
Let's assume a nearby strike could generate thousand of
volts on interior building wires. Then same EM field must
damage the low voltage RF amplifier transistors in every
nearby automobile radio (powered on or off). Then every
nearby TV receiver connected to an aerial would be damaged.
Then every TV and cable modem connected to long CATV cables
would be damaged. Why are TVs, portable and auto radios not
routinely destroyed by nearby strikes? Because a massive
voltage transient advocated by myths does not really exist.
Well actually TV and Cable modems are Routinely damaged by Lightning Strikes
after a near strike but for the Sake of his usual erronous view of Lightning
w_tom would have us not belive that it is just like w_toms other myths . for
the sake of those who think w_tom might have any credibility let me run
through some of the more amusing myths w_tom believes:

w_tom believes a Thermal Fuse protects against over current

w_tom Believes Lightning is a 'Low energy event'

w_tom Believes there is a 'direct connection between AC mains and the
Integrated circuits
in a modern modem' for me.

w_tom Believes 0.6mm diameter single strand copper wire has a lower
impedance
than 2.5mm square multistrand copper wire and therefore provides a better
earth.

w_tom Believes Telco gear and TV/Radio Transmitters never ever suffer
Lightning damage.

Tell me w_tom how long your 1KJ mov lasts in a Direct Lightning strike ?

how long does a surge last w_tom ? - what is the definition of a surge ?

Remind me again w_tom when the MOV was developed ?

But then again I am probably assuming w_tom understands enough basic physics
to answer these questions.....
Post by w_tom
Does the transistor side of a 50 meter cable also need a
surge protector? Why? Anything that a plug-in protector will
provide is already inside that equipment. Electronic
equipment has sufficient internal protection.
Yeah Right ! well in this thread we were talking about PA systems and I can
assure you that in the event of a near strike the protection diodes at the
input of a mixing desk may survive but then again they may also go Short - I
recently serviced a PA after a strike on the building next door to the one
in which it was installed (Near strike) and although the damage was not as
bad as if the building had had a direct strike the body count was :

Mackie SR24-4 8 Channels dead : 8 pairs of blown protection Diodes in
addition in 2 channels the input Transistors were also shot
2 Australian monitor 1K2 Amplifiers blown output devices (Mosfets)
1 Klark Technik DI (opamp in the output was blown)
Post by w_tom
But that
'manufacturer provided' protection may be overwhelmed if a
transient is not earthed 1) at service entrance and 2) distant
from the transistor.
Nope sorry all the damage was on the Inputs of the equipment there was (and
often is not ) any damage on the AC mains side of the equipment
Post by w_tom
BTW, a reason for promoting myths about massive surges on
that 50 meter wire is that, well, what is the alternative?
Otherwise we would stop buying those useless plug-in
protectors.
BTW a reason for promoting the myth that most Lightning damage enters via
the AC Mains ?
well it seems plausible,
It lets w_tom pontificate on a subject he knows little about (Lightning
protection),
and it sells 'whole house protection"

Actually when you apply basic physics to the whole debate a good plug in
surge protector is usually going to provide better protection in most cases
than 'whole house protection' as it provides protect closer to the Device
being protected - in reality who cares how high the device floats above
ground just so long as the Potential difference across the components are
reduce to below their breakdown Voltage.

You see an integral part of w_toms misunderstanding about Lightning damage
is that he (in his ignorance) assumes all damage is due to over current -
this is fine if you are an Electrician and used to thinking about pieces of
wire but when it comes to say Semiconductors Particularly if powered up at
the time.
Post by w_tom
Ballpark numbers demonstrate no 'surge' on that 50 meter
wire. Perform the experiment.
tell that to Benjamin Franklin......
Post by w_tom
Hang a 50 meter wire antenna
with one end attached to earth via an NE-2 glow lamp. Then
notice how often that neon glow lamp is 'destroyed' by nearby
lightning strikes. At best, milliamps from EMP might cause
the NE-2 to glow in a dark room. EMP is that insignificant.
If induced transients cannot even destroy an NE-2 glow lamp,
then how will transients overwhelm protection already inside
electronic devices?
Tell that to people who run Transmitters ... tell that to people whos TV
sets fail after a near strike when they tell you 'but the Lightning hit the
Tree next door"
Post by w_tom
Please explain where your EMP induced surge is?
on any piece of wire during a Near Strike ( Typically a Strike within 100M -
depending on the strength of the Strike)
Post by w_tom
Define it
in terms of common mode or differential mode current -
important parameters when discussing transients.
Depends on how the building is wired
Post by w_tom
Please
explain how many hundreds of volts with sufficient current can
be induced on an interior 50 meter wire
Hundreds of Volts ??? Believe me the input to a mixer is usually Toast well
before it cops hundreds of volts as for current exceed the breakdown voltage
of a powered up semiconductor and the internal power supply will often
provide the current (same concept as a flashover you have heard of them have
you ????)

while tens of volts
Post by w_tom
necessary to destroy RF transistors is not induced on TV
It often is and TV sets and VCrs are often damaged during near strikes this
despite the fact that they usually have surge protection on their inputs
Post by w_tom
portable radio?
what like a small Battery powered Transistor radio ?
Post by w_tom
Please explain why decades of proven
protection designs are wrong?
Not wrong merely not 100% effective and to be considered by most sane people
as a 'line of last resort" only
Post by w_tom
A common mistake - many confuse a direct strike as a nearby
one. For example, too many don't even know an internal
computer modem connects hardwire to an AC electric wire.
This is one of w_toms dearest Fantasies as it enables him to explain why the
vast majority of Lightning damage in computer installations shows a clear
path from a Modem or Modems rather than from AC mains. Unfortunately for
w_tom this is simply not True.

w_tom you still have not identified this Direct connection between the
electronics in a Modem and the AC wire - not surprising really since it does
not exsist.

It is funny that the vast majority of modern Modems I see are 'double
insulated' that is they are carefully insulated from AC mains and usually
use a plug pack and a simple test with a multi meter will soon tell you that
the AC mains is well insulated from the secondary side of the plug pack and
hence the rest of the modem
Post by w_tom
Therefore modem must have been damaged by EM fields of a
nearby CG strike since that AC wire connection does not
exist.
or direct strikes on the phone lines Since that direct Connection certainly
does not exsist.
Post by w_tom
Or they think a CG strike to the nearby tree did not
also strike those incoming utility wires (lightning can
dance).
what like the Tango ???
what drugs are you popping w_tom ?
Lightning can branch but once an Ionised path is established to earth
Lightning ususally keeps following that path. the path can be blown around
to some extent by wind but does not usually go to far
Post by w_tom
Or they think a relay separates electronics from an
incoming utility wire. To a transient, the relay's wiper
connects directly to the relay coil as defined in specs by
breakdown voltage.
Probably just another depraved fantasy by w_tom
Post by w_tom
Just three reasons why some might not
understand it was a direct strike - and then assume it must
have been EMP. If it was EMP, then every nearby portable AM
radio was destroyed.
nope sorry cant make much sense of this delusion
Post by w_tom
Post by Chris Hornbeck
Post by w_tom
That 50 meters distance provides additional
protection for transistors. If protectors were adjacent to
transistors, then protection would be compromised. (Plug-in
protectors would have you not know this).
Yabut, in a normal installation wouldn't this 50 meters
(or whatever) be unburied, and thus a large antenna?
...
Perhaps we differ mainly in what we consider to be the
greater (or perhaps the more common) threat. My experience
has been that for modern electronics the greatest threat
comes via EMP. Direct conduction strikes are statistically
rarer and of course bigger.
Ahh but then you do not live in w_toms fantasy land and probably have a lot
more experience with Lightning damage than w_tom

Regards
Richard Freeman
Scott Dorsey
2003-12-30 15:01:06 UTC
Permalink
Post by Chris Hornbeck
Post by w_tom
What part of that 50+ year old technology did you not
understand? Posted here was demonstrated effective annually in
millions of locations throughout the world for generations -
including your own home town. Which part did you not
understand?
Well, the part about the earth ground contributing to the
protection of semiconductors some significant distance away.
It can, IF the problem is a pulse coming in on the power line itself.

But, if there is a nearby lightning strike, there will be current induced
in the cable between the surge suppressor and the equipment. This is why
you need BOTH an arrestor at the panel AND properly designed power supplies
with internal surge suppression.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Noel Bachelor
2003-12-31 07:42:54 UTC
Permalink
Post by Chris Hornbeck
Post by w_tom
What part of that 50+ year old technology did you not
understand? Posted here was demonstrated effective annually in
millions of locations throughout the world for generations -
including your own home town. Which part did you not
understand?
Well, the part about the earth ground contributing to the
protection of semiconductors some significant distance away.
I'm merely suggesting that you rethink your model. No need
to get upset.
Don't worry Chris. It's his personal crusade. I've had a bit of a
discussion on this once or twice on comp.sys.laptops. He doesn't see how
protection can be done anyother way. By his theory, portable gear can
never be protected if you don't own the building.


Noel Bachelor noelbachelorAT(From:_domain)
Language Recordings Inc (Darwin Australia)
Richard Freeman
2003-12-31 03:58:29 UTC
Permalink
Post by w_tom
Surge protection is earth ground. There is no way around
that so fundamental fact. In your mobile situation, place
shunt mode protector components as close to earth ground and
as far from transistors as is possible. IOW put a largest
joule protector at the far end of power cord at wall
receptacle or in another outlet that is 1) on same phase, and
2) closest to earth ground. One receptacle might be attached
to the main breaker box.
Of course this does not protect against the most common Paths of Lightning
damage - Emp from cabling (particularly multi-core) blowing the shite out of
your delicate mic pre-amps...
Post by w_tom
Of course, let's keep this all in perspective. Destructive
transients occur typically once every eight years; variance
determined by local conditions such as geology.
Actually far rarer than this ! as the MEN power distribution system does a
pretty good job of absorbing Lightning strikes. in fact the far more common
path of Lightning damage is from near/direct strikes inducing current into
cabling such as : multicores, Speaker Leads, Phone lines etc
Post by w_tom
If earth ground does not exist, then nothing will provide
effective protection.
this is actually BS protection usually involves making the spike/surge
common mode across all the equipment and riding out the surge and w_tom
should know this as he advocates a single Earth stake in his 'Lightning
protection' schemes.
It is a well known fact that in a near or direct strike a single earth stake
will often develop an EPR (Earth Potential Rise aka GPR or as described at
w_toms favorite source http://www.polyphaser.com/ppc_PEN1014.asp ) of 10,000
Volts above earth or (often) more.
The earthing systems required for Transmitters (which do come pretty close
to an effective earth) actually involve multiple Earth stakes often spread
out over 1/2 an Acre or more (depending on the earth conductivity) linked by
very fat multi strand pieces of cable or bus bars and even then Transmitter
still occasionally suffer from Lightning damage.

- unfortunately in a typical PA system this is impractical as you usually
have a nice long Multicore connecting your Desk/effects with the stage and
just waiting to pick up Emp from Lightning (as well as two effectively
different power sources) or even just mic cabling across the stage.

Lightning protection for a PA system (well actually many things really) is a
pretty hard ask when you consider all the potential paths for Lightning
.
Telco installations typically have pretty good protection - effectively
consisting of keeping everything in an earthed metal box and yet they still
suffer damage and as for w_toms much touted 1KJ 'whole house protection'
well I have seen far too many incinerated Movs (of varying ratings including
1KJ and greater see http://www.nettally.com/saints/lightning.html for an
example and believe me that MOV is pretty well intact compared to many I
have seen) to blithely put my faith in them completely - yes a MOV may save
you but they are a bit like polyswitches protecting speakers, they simply do
not always work and are a line of absolute last desperate resort only.
Merely protecting against Lightning on the AC mains is like protecting
yourself from being mugged when you are at home and not worrying about it
when you are walking down a dark alley in a seedy part of the city late at
night - yes you can get mugged at home but it is very rare (well it might
not be the best illustration depending on where you live! :-) and is much
more likely to happen on the street at night (well in the late afternoon in
Parramatta !).

Bottom line is when Lightning comes a calling you want to have everything
unplugged - not merely turned off and when I say unplugged I dont mean
merely the power you also need to include Mic, Guitar and Speaker leads if
you choose to keep the system running (and I have) remember that that is a
calculated risk and in the event of a near or direct strike you will have to
take gear to get it serviced.

Of course a far more likely source of damage (and I have seen this a few
times) is a badly wired power system in an unknown venue with your equipment
ending up between phase rather than phase and Neutral and a good Power
conditioner should protect against this.

Regards
Richard Freeman
Mike Rivers
2003-12-31 13:25:57 UTC
Permalink
Post by Richard Freeman
- unfortunately in a typical PA system this is impractical as you usually
have a nice long Multicore connecting your Desk/effects with the stage and
just waiting to pick up Emp from Lightning (as well as two effectively
different power sources) or even just mic cabling across the stage.
Lightning protection for a PA system (well actually many things really) is a
pretty hard ask when you consider all the potential paths for Lightning
Lightning protection is usuall on the building, not its contents. If
you have a PA system installed in an auditorium, it's reasonable to
assume that there will be something that will protect the building
from fire as a result of a lightning strike, and that will also divert
much of the electromagnetic energy away from your sensititive inputs
as the building acts as an overall shield. But of course if you have a
cable laying across the ground or strung between trees or scaffolds
outdoors, when the blitzen starts blitzing, you have to make the
decision (often you don't have a choice) of shutting down the PA
system and disconnecting the "antennas" or letting the show go on
until the audience decides to leave.
Post by Richard Freeman
Bottom line is when Lightning comes a calling you want to have everything
unplugged
Either that or you have to take your chances and let the show go on.
The promoter isn't going to excuse the lack of sound until he hears a
loud pop from the speakers, a blast of hum, and and then everything
goes completely dead. If you try to tell him "I'm afraid of my gear
being damaged and I want to shut it down" he'll probably have a heart
attack worrying about the riot.


--
I'm really Mike Rivers (***@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Richard Freeman
2003-12-31 22:03:41 UTC
Permalink
Post by Mike Rivers
Post by Richard Freeman
- unfortunately in a typical PA system this is impractical as you usually
have a nice long Multicore connecting your Desk/effects with the stage and
just waiting to pick up Emp from Lightning (as well as two effectively
different power sources) or even just mic cabling across the stage.
Lightning protection for a PA system (well actually many things really) is a
pretty hard ask when you consider all the potential paths for Lightning
Lightning protection is usuall on the building, not its contents. If
you have a PA system installed in an auditorium, it's reasonable to
assume that there will be something that will protect the building
from fire as a result of a lightning strike, and that will also divert
much of the electromagnetic energy away from your sensititive inputs
as the building acts as an overall shield. But of course if you have a
cable laying across the ground or strung between trees or scaffolds
outdoors, when the blitzen starts blitzing, you have to make the
decision (often you don't have a choice) of shutting down the PA
system and disconnecting the "antennas" or letting the show go on
until the audience decides to leave.
well Lightning protection on buildings is a whole new ballgame and when you
are talking a large Auditorium then it usually is Lightning protected with
Lightning Rods etc however this is usually designed Primarily with building
protection in mind and a 100,000 amp surge down a Lightning rod is still
going to produce one heck of an EMP......
Post by Mike Rivers
Post by Richard Freeman
Bottom line is when Lightning comes a calling you want to have everything
unplugged
Either that or you have to take your chances and let the show go on.
The promoter isn't going to excuse the lack of sound until he hears a
loud pop from the speakers, a blast of hum, and and then everything
goes completely dead. If you try to tell him "I'm afraid of my gear
being damaged and I want to shut it down" he'll probably have a heart
attack worrying about the riot.
well I believe that was what I also said that leaving the system running was
a calculated risk hang on let me return the bit you snipped :

if
you choose to keep the system running (and I have) remember that that is a
calculated risk and in the event of a near or direct strike you will have to
take gear to get it serviced.

In cases where a Thunderstorm has blown in while I have been setting up a
rig I have chosen to run the System for the Gig however I have also
disconnected the Multicores etc as soon as Soundcheck was over until the Gig
was about to start (of course you need Multicores with Multipin connectors)
Fortunately Thunderstorms (in this part of the world Australia) tend to blow
over pretty quickly.
Post by Mike Rivers
--
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Martin Glasband
2003-12-26 08:43:49 UTC
Permalink
A decent isolation transformer with at least one Faraday shield may not be
considered a surge protector by definition because it does not "clamp" like
an MOV or similar. However it's the nature of the beast to block voltage
transients because transformers are essentially magnetic devices and spikes
usually have very little current. Also, a grounded Faraday shield
interposed between the input and output coils further adds to the
protection.

When we build such units, they are tested at the factory as a part of the UL
certification for UL/ANSI Std. #1012 which requires a hi-pot test. In this
case, the test consists of applying 1500V across the primary circuit for a
full minute without there being any incidence of voltage leakage. This is
about as close as you will ever get to simulating a transient voltage (in
this case with a long duration).

I realize that this is a more expensive way of dealing with the problem
however if you already have such an isolation transformer in your power
chain, additional surge protection is usually less efficient and subject to
blowing up or sacrificing itself and also redundant.

Perhaps a "whole house" or local breaker panel device would be just as
inexpensive and it would protect not only the studio equipment but the rest
of the electronics in the building as well. Most electrical manufacturers
offer a "circuit breaker-like" plug in device that goes right in the breaker
box. But for portable racks, you are on your own.
Post by Steven Shelikoff
I'm putting together a little rack for live performance and like any
good consumer, I'm checking out the surge and spike specs for power
conditioners. I want to protect my investment. I need only 15 amps but
am looking at the 20 amp ones as well if the price is right. Some form
of EMI/RFI noise supression is required but I'm more interested in
protecting the equipment from unknown power sources then getting rid of
that last little bit of noise. Bells and whistles like volt meters,
ammeters, lights, etc. are nice but not really required.
Let me know if I have my terms right because they're pretty confusing.
Clamping voltage: the highest voltage the equipment should see when a
spike hits. The lower the better.
Response time: the time a surge protector has to "kick in". The lower
the better. On the order of 1 nanosecond is common.
Those first 2 determine how well the surge supressor protects the
equipment. The next 3 determine how well the surge supressor protects
itself.
Max voltage: highest single voltage spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.
Max current: highest single current spike the protection circuit can
withstand before it breaks down and damages the surge protector
(hopefully not the equipment it protects). The higher the better.
Max energy: cumulative amount of energy from all of the spikes the surge
protector has seen before it's clamping voltage spec increases by 10%.
The higher the better. This one determines pretty much how long the
surge protector will last in normal service compared to other surge
protectors if they never see *really big* spikes that exceed the max
voltage and max current.
Hopefully I have all those things correct above. If not, please feel
free to correct me. Now on to the numbers from the manufacturer's
clamping voltage, response time, max voltage, max current and max
energy. Also, the last spec is noise attenuation (higher the better).
ETA PD8/PD8L
330V, < 1 nanosecond, N/A, 65000A, 1665 joules, up to 68 dB
150kHz-100MHz
ETA PD9L
N/A, 1 nanosecond, 6000V, 12000A, 450 joules, >35 dB 1.5kHz-200MHz
ETA PD11LV
330V, < 1 nanosecond, N/A, 6500A, 630 joules, up to 20 dB 150kHz-200MHz
ETA PD11SS
200 V, 1 nanosecond, 6000 V, 12000 A, 450 joules, >35 dB 1.5kHz-200MHz
ETA PD11P
200 V, 1 nanosecond, 6000 V, 23000 A, 630 joules, >20 dB 1.5kHz-200MHz
ETA PD11SP
200V, 1 nanosecond, 6000 V, 26000 A, 630 joules, >35 dB 1.5kHz-200MHz
ETA PD11LVSP/PD11SSP
200V, 1 nanosecond, 6000 V, 26000 A, 630 joules, >20 dB 1.5kHz-200MHz
Furman PL-PLUSD/PL-PLUSDM/PM-8DM
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, >40 dB 1MHz-200MHz
Furman PS-8/PS-8R/PL-PLUS/PM-8
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, 20dB 200kHz, >40 dB
1MHz-200MHz
Furman PL-8
400 V, 1 nanosecond, N/A, 6500 A, 240 joules, N/A
Furman PL-PROD/PL-PRODM/PM-PRODM/PM-PRO/PS-PRO/PL-PRO
400 V, 1 nanosecond, N/A, 11000 A, 550 joules, >40 dB 1MHz-200MHz
Furman RR-15NL/RR-15/RR-15-PLUS
N/A, N/A, N/A, N/A, 102 joules, >20 dB 1.5MHz-200MHz
Furman RP-8/RP-8L/RP-8D
250V, N/A, N/A, 4500A, 102 joules, >20 dB 1.5MHz-200MHz
Nady PCL-800/PCL-810/PCL-815
N/A, N/A, N/A, N/A, N/A, N/A
Powerwerks 1630
250 V, 1 nanosecond, N/A, 19500 A, 240 joules, 20 dB at 200kHz
Samson PS9/PB9/Pro7 (from the owners manual)
340 V, 1 nanosecond, N/A, 4500 A, 56 joules, > 20dB 1.5MHz-200MHz
Samson PB9 (from brochure)
400 V, 1 nanosecond, N/A, 8000 A, 85 joules, > 20dB 1.5MHz-200MHz
330 V, N/A, N/A, N/A, N/A, 510 joules
What is Nady hiding? They don't give any specs in their literature.
The Samson has nice features like the tray but at 56 joules, it won't
last long before you have to replace the surge suppression components.
Why can't Samson get their specs consistent?
The Furmans, which I see everywhere, have a high clamping voltage
(except for the older RP line). Correct me if I'm wrong, but I don't
think they can even pass UL certification with clamping voltage that
high. They are also middle of the road in terms of how much spike
energy they can absorb.
The ETAs look like the best overall supressors with the cheap Powerwerks
coming in a close second. My $10 power strip does a pretty good job as
well but I don't think it has any EMI/RFI filtering at all.
Anyone have any comments, recommendations? Why do I see Furmans all
over the place? Is it just marketing?
Steve
Mike Rivers
2003-12-26 13:11:55 UTC
Permalink
Post by Martin Glasband
When we build such units, they are tested at the factory as a part of the UL
certification for UL/ANSI Std. #1012 which requires a hi-pot test. In this
case, the test consists of applying 1500V across the primary circuit for a
full minute without there being any incidence of voltage leakage. This is
about as close as you will ever get to simulating a transient voltage (in
this case with a long duration).
When combining the ability to tolerate a high voltage with the natural
filtering characteristics of the inductance, you have some protection
against surges, but what you don't have is protection from short term
very high voltages which often can have significant current behind
them. A lightning strike on or near a power line can introduce
thousands of volts at hundreds of amperes for a few microseconds
(lightning being RF energy). There's lots of joules there and without
the capacity to absorb the energy and release it at a safely slow
rate, you can have damage to what's on the other side.



--
I'm really Mike Rivers - (***@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Martin Glasband
2003-12-26 18:08:15 UTC
Permalink
In the case of a direct or even a near lightning strike, only God can help
you. Just don't have your ear to a headpiece of a landline phone either.

I once had such an experience when a near lighting strike came through my
phone line. I was using a pretty high rated Tripplite surge protection unit
on my computer (phone and AC) and the spike still toasted the modem and also
flamed right through it and burned the video card next to it. High current
spikes such as lightning are beyond the reach of most surge protection
devices save for the most expensive ones used in radio and tv broadcast
towers. But even they are quickly diminished and won't survive a single
such strike. But in ordinary circumstances, a grounded faraday shield like
I described will shunt anything that shoots through the primary coil and
escapes it. But since 99% or better of all voltage spikes are caused by a
faulty or damaged induction load on the same line, the current is
negligible, certainly a lot less than a hi-pot tester at 1500 volts.

I will elaborate on this just a bit more relating an experience I had about
10 years ago. A friend was cutting a 24-bit CD on a $30,000 Yamaha CD
burner in his VERY expensive 24-bit studio. (10 years ago) Since his home
was "offline" and he had no utility power, he used a sophisticated inverter
that was battery driven. That's what a lot of people who live in the
boonies wind up doing. During one of his recording sessions, a fire broke
out in his "power bus" outside where he kept the inverter. There was a pink
plasma fire around the unit and ultimately, the only thing he could do to
cut off the power was to use a dielectric pair of tree trimmers to cut the
DC cables. No one wanted to go anywhere near any of the equipment. During
the incident, he was merrily cutting his CD and knew nothing of the problem.
A friend had to alert him that there was a fire in his bus. When the
incident passed, literally everything AC in his house was fried. His TV,
clock radio, microwave oven, answering machine, home stereo.... all of it
toast. But his 24-bit studio protected by the isolation transformer (and a
feroresonant transformer also in the line to be honest) survived undamaged.

I have also experienced this extreme surge situation where people I know in
Colorado have a studio where there are many lighing storms. The incidence
of spikes was very large. During an episode of these events, the output of
the transformer was monitored with a spectrum analyzer. It was found that
when a lightning strike occurred, all low frequency energy from the spike
was attenuated however it was noted that a "burst" of high frequency data
did manage to bleed through, but the amplitude was extremely small. He did
experience some data corruption when these events occurred, however nothing
of a catastrophic nature ever damaged any of his electronics. It was
decided after all of this that what he needed was add an MOV array in front
of the transformer which successfully clamped the high frequency energy.
However this was done not so much as a protection method, rather it was done
to filter out high frequencies that seemed to pass through the transformer
as noise during a lightning event and corrupt his data.
Post by Mike Rivers
Post by Martin Glasband
When we build such units, they are tested at the factory as a part of the UL
certification for UL/ANSI Std. #1012 which requires a hi-pot test. In this
case, the test consists of applying 1500V across the primary circuit for a
full minute without there being any incidence of voltage leakage. This is
about as close as you will ever get to simulating a transient voltage (in
this case with a long duration).
When combining the ability to tolerate a high voltage with the natural
filtering characteristics of the inductance, you have some protection
against surges, but what you don't have is protection from short term
very high voltages which often can have significant current behind
them. A lightning strike on or near a power line can introduce
thousands of volts at hundreds of amperes for a few microseconds
(lightning being RF energy). There's lots of joules there and without
the capacity to absorb the energy and release it at a safely slow
rate, you can have damage to what's on the other side.
--
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
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