Surge Protectors

Are surge protectors based on grounding or diode clipping?




- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

[Jim Yanik]

vjp2.at@at.BioStrategist.dot.dot.com wrote in
news:htioft$8nr$2@reader1.panix.com:

Are surge protectors based on grounding or diode clipping?

grounding. once the breakover voltage is reached,the surge is conducted to
ground.

Otherwise,the surge would just find it's own way to ground,through your
device,catastrophically. and you have to have a good ground,as grounds can
float above true ground,particularly in poor soils,like Florida's sandy
soil.

--
Jim Yanik
jyanik
at
localnet
dot com

 

[whit3rd]

On May 26, 2:09 am, vjp2...@at.BioStrategist.dot.dot.com wrote:

Are surge protectors based on grounding or diode clipping?

Both. Most surge suppressors have a conducts-on-overvoltage
element directly across the line, with a fuse or circuit breaker to
keep the fire hazard low. Additional elements that connect to the
protective ground pin are of secondary importance.

The conducts-on-overvoltage element is usually a metal oxide
varistor, a kind of crude semiconductor breakover diode.

 

Thanks for both replies.


- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

[GregS]

In article <f026ebce-f1d8-4dc2-83f3-4847ef4dcf64@o12g2000vba.googlegroups.com>, whit3rd <whit3rd@gmail.com> wrote:

On May 26, 2:09=A0am, vjp2...@at.BioStrategist.dot.dot.com wrote:
Are surge protectors based on grounding or diode clipping?

Both. Most surge suppressors have a conducts-on-overvoltage
element directly across the line, with a fuse or circuit breaker to
keep the fire hazard low. Additional elements that connect to the
protective ground pin are of secondary importance.

I would argue that. The differential surpressor is fine, but the common
mode surge can do more harm and a lot of noise problems. Using an isolation transformer
makes common mode problems impossible. Its a direct short to ground.

greg

The conducts-on-overvoltage element is usually a metal oxide
varistor, a kind of crude semiconductor breakover diode.

 

[Jim Yanik]

zekfrivo@zekfrivolous.com (GregS) wrote in
news:htlreq$mlf$1@usenet01.srv.cis.pitt.edu:

In article
f026ebce-f1d8-4dc2-83f3-4847ef4dcf64@o12g2000vba.googlegroups.com>,
whit3rd <whit3rd@gmail.com> wrote:
On May 26, 2:09=A0am, vjp2...@at.BioStrategist.dot.dot.com wrote:
Are surge protectors based on grounding or diode clipping?

Both. Most surge suppressors have a conducts-on-overvoltage
element directly across the line, with a fuse or circuit breaker to
keep the fire hazard low. Additional elements that connect to the
protective ground pin are of secondary importance.

I would argue that. The differential surpressor is fine, but the
common mode surge can do more harm and a lot of noise problems. Using
an isolation transformer makes common mode problems impossible. Its a
direct short to ground.

greg


The conducts-on-overvoltage element is usually a metal oxide
varistor, a kind of crude semiconductor breakover diode.

it's not a "diode",its just a sintered semi-metallic pellet that conducts
once a certain voltage is reached.
a "diode" is a P/N junction or a semiconductor/metal junction.
even the cheap suppressors I've bought had 3 MOVs,one for each leg to
ground and from one leg to the other. I guess that's a "delta" config.

--
Jim Yanik
jyanik
at
localnet
dot com

 

[whit3rd]

On May 27, 8:53 am, Jim Yanik <jya...@abuse.gov> wrote:

zekfr...@zekfrivolous.com (GregS) wrote innews:htlreq$mlf$1@usenet01.srv.cis.pitt.edu:

Are surge protectors based on grounding or diode clipping?

Both.  Most surge suppressors have a conducts-on-overvoltage
element directly across the line, with a fuse or circuit breaker to
keep the fire hazard low.

The conducts-on-overvoltage element is usually a metal oxide
varistor, a kind of crude semiconductor breakover diode.

it's not a "diode",its just a sintered semi-metallic pellet that conducts
once a certain voltage is reached.
a "diode" is a P/N junction or a semiconductor/metal junction.

The metal oxide in a MOV is certainly a semiconductor. The breakover
is due to avalanche multiplication rather than minority injection.
The oldest
ones were SiC (basically, just grinding wheels with electrodes bolted
on).
It has two leads, so it's a diode. It's made with a semiconductor, so
it's a semiconductor diode. It isn't a rectifier diode, though.
DIAC and current regulator two-terminal devices are also diodes,
but aren't simple PN junction types (don't really rectify).
Vacuum tubes are sometimes diodes, too (like my microwave oven's
magnetron).

even the cheap suppressors I've bought had 3 MOVs,one for each leg to
ground and from one leg to the other. I guess that's a "delta" config.

The protective ground connection is, in most situations, carrying no
current. The MOVs that connect to that protective ground are not so
much
protecting the plugged-in device, as they are dumping transient energy
in
the building's wiring (protecting the building rather than the
appliance).
The internal suppressors on lots of consumer equipment only have
one MOV, across the line, not the full trio that is common in third-
party
suppressor modules.

 

[GregS]

In article <6a2cfce3-46ea-472c-834d-cb47729d1d63@v18g2000vbc.googlegroups.com>, whit3rd <whit3rd@gmail.com> wrote:

On May 27, 8:53=A0am, Jim Yanik <jya...@abuse.gov> wrote:
zekfr...@zekfrivolous.com (GregS) wrote innews:htlreq$mlf$1@usenet01.srv.=
cis.pitt.edu:

Are surge protectors based on grounding or diode clipping?

Both. =A0Most surge suppressors have a conducts-on-overvoltage
element directly across the line, with a fuse or circuit breaker to
keep the fire hazard low.

The conducts-on-overvoltage element is usually a metal oxide
varistor, a kind of crude semiconductor breakover diode.

it's not a "diode",its just a sintered semi-metallic pellet that conducts
once a certain voltage is reached.
a "diode" is a P/N junction or a semiconductor/metal junction.

The metal oxide in a MOV is certainly a semiconductor. The breakover
is due to avalanche multiplication rather than minority injection.
The oldest
ones were SiC (basically, just grinding wheels with electrodes bolted
on).
It has two leads, so it's a diode. It's made with a semiconductor, so
it's a semiconductor diode. It isn't a rectifier diode, though.
DIAC and current regulator two-terminal devices are also diodes,
but aren't simple PN junction types (don't really rectify).
Vacuum tubes are sometimes diodes, too (like my microwave oven's
magnetron).

even the cheap suppressors I've bought had 3 MOVs,one for each leg to
ground and from one leg to the other. I guess that's a "delta" config.

The protective ground connection is, in most situations, carrying no
current. The MOVs that connect to that protective ground are not so
much
protecting the plugged-in device, as they are dumping transient energy
in
the building's wiring (protecting the building rather than the
appliance).
The internal suppressors on lots of consumer equipment only have
one MOV, across the line, not the full trio that is common in third-
party
suppressor modules.

I thought there were NO supressors in most consumer equipment
because its a liability.

Its the line to ground noise and surges that cause TTL computer type equipment
to BOMB OUT. Ground has everything to do with functioning circuits, that use ground
for reference. Of, course, its best not to use ground for reference.

greg

 

[Jim Yanik]

zekfrivo@zekfrivolous.com (GregS) wrote in
news:htmh5b$rcn$1@usenet01.srv.cis.pitt.edu:

In article
6a2cfce3-46ea-472c-834d-cb47729d1d63@v18g2000vbc.googlegroups.com>,
whit3rd <whit3rd@gmail.com> wrote:
On May 27, 8:53=A0am, Jim Yanik <jya...@abuse.gov> wrote:
zekfr...@zekfrivolous.com (GregS) wrote
innews:htlreq$mlf$1@usenet01.srv.=
cis.pitt.edu:

Are surge protectors based on grounding or diode clipping?

Both. =A0Most surge suppressors have a conducts-on-overvoltage
element directly across the line, with a fuse or circuit breaker
to keep the fire hazard low.

The conducts-on-overvoltage element is usually a metal oxide
varistor, a kind of crude semiconductor breakover diode.

it's not a "diode",its just a sintered semi-metallic pellet that
conducts once a certain voltage is reached.
a "diode" is a P/N junction or a semiconductor/metal junction.

The metal oxide in a MOV is certainly a semiconductor.

I never said otherwise. but it's NOT a "diode".

The breakover
is due to avalanche multiplication rather than minority injection.
The oldest
ones were SiC (basically, just grinding wheels with electrodes bolted
on).
It has two leads, so it's a diode.

No,it's not.

from the Free Dictionary;
1.An electronic device that restricts current flow chiefly to one
direction. 2. An electron tube having a cathode and an anode. ...

Other Google examples for "diode definition" are essentially the same.

A thermistor is another semiconductor,with two leads,yet NOT a "diode",but
a resistor.An MOV is closer to "resistor" than "diode".
a Polyfuse is another semiconductor with two leads,yet not a "diode".

It's made with a semiconductor, so
it's a semiconductor diode. It isn't a rectifier diode, though.
DIAC and current regulator two-terminal devices are also diodes,
but aren't simple PN junction types (don't really rectify).
Vacuum tubes are sometimes diodes, too (like my microwave oven's
magnetron).

even the cheap suppressors I've bought had 3 MOVs,one for each leg
to ground and from one leg to the other. I guess that's a "delta"
config.

The protective ground connection is, in most situations, carrying no
current. The MOVs that connect to that protective ground are not so
much
protecting the plugged-in device, as they are dumping transient energy
in
the building's wiring (protecting the building rather than the
appliance).

MOVs -shunt- surge energy to ground,through the wiring.
sometimes,they cannot handle the energy,and blow apart.I've had to replace
more than a few of them,living in the Lightning Capitol of the US,central
Florida. Sometimes,the surge energy finds a better path through the
protected device,with unfortunate results.

The internal suppressors on lots of consumer equipment only have
one MOV, across the line, not the full trio that is common in third-
party
suppressor modules.


I thought there were NO supressors in most consumer equipment
because its a liability.

no,just an extra cost.
plus,after they absorb a strike,they often need replacement,along with the
blown fuse.

Its the line to ground noise and surges that cause TTL computer type
equipment to BOMB OUT. Ground has everything to do with functioning
circuits, that use ground for reference. Of, course, its best not to
use ground for reference.

greg

even with floating circuits,a lightning strike will find some path to
ground. Probably one that is destructive.

--
Jim Yanik
jyanik
at
localnet
dot com

 

[whit3rd]

On May 27, 1:44 pm, Jim Yanik <jya...@abuse.gov> wrote:

zekfr...@zekfrivolous.com (GregS) wrote innews:htmh5b$rcn$1@usenet01.srv.cis.pitt.edu:

The conducts-on-overvoltage element is usually a metal oxide
varistor, a kind of crude semiconductor breakover diode.

it's not a "diode",its just a sintered semi-metallic pellet that
conducts once a certain voltage is reached.
a "diode" is a P/N junction or a semiconductor/metal junction.

The metal oxide in a MOV is certainly a semiconductor.  

I never said otherwise. but it's NOT a "diode".

from the Free Dictionary;
1.An electronic device that restricts current flow chiefly to one
direction. 2. An electron tube having a cathode and an anode. ...

Other Google examples for "diode definition" are essentially the same.

How sad. Diode, meaning two electrodes... applies to a variety
of semiconductor devices, and vacuum tubes. Not just rectifiers,
but tunnel diodes and gunn diodes and those self-blinking
LEDs (really oscillator integrated circuits with a lamp).
The dictionary is wrong. MOVs are semiconductor devices
equivalent to avalanche (Zener) diodes, but without any
forward-bias conduction. They're semiconductor diodes in
all senses of the words.

 

[Michael A. Terrell]

vjp2.at@at.BioStrategist.dot.dot.com wrote:

*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.

There should already be one inside the phone company's Network
Interface.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

 

Well, here's is a disclosure of the biases which might be distorting my
thinking: In February and August 2001 I lost two external modems to lightning
(caused my line to be off-hook until disconnected modems) and someone on
usenet told me to tie a ground to the modem. That particular computer (Ampro
2210 80186 hooked up to 1980 HP2621a terminal) with modems had previously
survived 1988-1995 without problems (no phone surge supressor but one on
power). In 2008 I lost two LCD monitors the same week during light rain. I
am therefore excessively (and probably unreasonably) cautious of using
computers during bad weather. Also in 1980 I took two semesters of EE for
non-EEs (am a 1981 ChE).

- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.


- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

 

[Cydrome Leader]

Michael A. Terrell <mike.terrell@earthlink.net> wrote:

vjp2.at@at.BioStrategist.dot.dot.com wrote:

*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.


There should already be one inside the phone company's Network
Interface.

This applies to the US-

there are surge and lightning arrestors on phone lines where they enter a residence, and they're
grounded to something good, like a water pipe for instance.

It works great.

Now if lightning surges hit your power then what happens?

a cheapo-garbage "surge protector" like a power strip or the like will use MOVs to short out line
to neutral or even line to ground.

What happens if you throw a short across line to ground and can somehow clamp it to 600 volts or
whatever? The numbers are made up, but concept is the same.

well, your ground ends up at 300 volts above actual earth ground where that device is located. This
assumes your ground has the same impedance as the current carrying conductors.

So now your computer isn't really grounded, and floating at a potential way off what the phone like
is at, which worst case is being protected to a really solid ground, and not hundreds of feet or
wiring in your walls or whatever.

This is what blows up stuff like modems or devices that sit between your outlets and a phone line.

The best move is to install a service entrance surge supressor. They'll clamp surges at the best
ground you've got, with the lowest possible impedance, and at your ground/nuetral bonding point not
at your load where any attempts to do so are pretty useless across the extra fraction of an ohm.

You can easily test the resistance of your wiring at home too, and at the same time actually test
if your ground is solid.

connect some large resistive loads like halogen lamps, hairdryer, toaster oven or whatever at and
outlet. Measure the voltage drop when it's on. Break out the suicide cables and test that same
device using line to ground.

Depending on how your place is wired, you may find that under an actual load, your ground is really
awful. A volt meter won't pick crappy ground connections unless you are actually running real
current through it, so just reading 120 across hot and ground and saying "looks good" really
doesn't count.

Trying to suppress a surge with a $4 power strip connected though 5 junction boxes connected with
BX cable can really just be a big joke.

 

[bud--]

Cydrome Leader wrote:

Michael A. Terrell <mike.terrell@earthlink.net> wrote:
vjp2.at@at.BioStrategist.dot.dot.com wrote:
*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.

There should already be one inside the phone company's Network
Interface.

This applies to the US-

there are surge and lightning arrestors on phone lines where they enter a residence, and they're
grounded to something good, like a water pipe for instance.

It works great.

Some comments are somewhat specific to the US.

A couple of excellent sources of info on surge protection are:
<http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf>
from the IEEE, and a much simpler one from the US-NIST
<http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf>

With a strong surge current to the earthing electrode, the "ground" for
the building can rise thousands of volts above "absolute" earth
potential. You want power and phone (and cable) wires rise together.
That requires a short ground wire from the telephone entrance protector
to the earthing system at the power service.

Now if lightning surges hit your power then what happens?

a cheapo-garbage "surge protector" like a power strip or the like will use MOVs to short out line
to neutral or even line to ground.

What happens if you throw a short across line to ground and can somehow clamp it to 600 volts or
whatever? The numbers are made up, but concept is the same.

well, your ground ends up at 300 volts above actual earth ground where that device is located. This
assumes your ground has the same impedance as the current carrying conductors.

So now your computer isn't really grounded, and floating at a potential way off what the phone like
is at, which worst case is being protected to a really solid ground, and not hundreds of feet or
wiring in your walls or whatever.

This is what blows up stuff like modems or devices that sit between your outlets and a phone line.

If you RTFM, any competent plug-in suppressor manufacturer should tell
you the phone wires have to go through the suppressor along with the
power wires. The voltage on all wires is clamped to the ground at the
suppressor. The voltage between the wires to the protected equipment is
safe for the protected equipment. All interconnected equipment needs to
be connected to the same suppressor, or external wires, like cable need
to go through the suppressor. This is clearly explained in the IEEE
guide starting pdf page 40, and shown in the examples at the end.
Plug-in suppressors work primarily by clamping, not earthing.

The best move is to install a service entrance surge supressor. They'll clamp surges at the best
ground you've got, with the lowest possible impedance, and at your ground/nuetral bonding point not
at your load where any attempts to do so are pretty useless across the extra fraction of an ohm.

Service panel suppressors are a real good idea. I would particularly use
one in high risk areas like Florida.

But from the NIST guide:
"Q - Will a surge protector installed at the service entrance be
sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances
[electronic equipment], No for two-link appliances [equipment connected
to power AND phone or cable or....]. Since most homes today have some
kind of two-link appliances, the prudent answer to the question would be
NO - but that does not mean that a surge protector installed at the
service entrance is useless."

The NIST guide suggests most damage results from high voltage between
power and phone/cable wires. A service entrance suppressor does not, by
itself, limit that voltage.

You can easily test the resistance of your wiring at home too, and at the same time actually test
if your ground is solid.

connect some large resistive loads like halogen lamps, hairdryer, toaster oven or whatever at and
outlet. Measure the voltage drop when it's on. Break out the suicide cables and test that same
device using line to ground.

Depending on how your place is wired, you may find that under an actual load, your ground is really
awful. A volt meter won't pick crappy ground connections unless you are actually running real
current through it, so just reading 120 across hot and ground and saying "looks good" really
doesn't count.

May well be worthwhile. But even with a good earth connection the
building ground can rise thousands of volts.

Trying to suppress a surge with a $4 power strip connected though 5 junction boxes connected with
BX cable can really just be a big joke.

Neither the IEEE or NIST agree. Both guides say plug-in suppressors,
used correctly, are effective. Plug-in suppressors with very high
ratings are readily and cheaply available. In the US you should only buy
suppressors listed under UL1449. UL tests include a testing to at least
a minimum floor of protection. UPSs with surge protection should also
have UL1449 listing.

==========
If there is a strong surge on power wires, with no power service
suppressor, at about 6kV there is arc-over from the hot busbars to the
service panel enclosure. After the arc is established, the arc voltage
is hundreds of volts. Since the enclosure is connected to
ground-neutral-earthing electrode, most of the surge energy is dumped to
earth. A surge is a short event, thus a relatively high frequency event.
The impedance of the branch circuit greatly limits the current to a
plug-in suppressor (unless the branch circuit is very short) and thus
limits the energy that can reach a plug-in suppressor. For both these
reasons the energy dissipated in a plug-in suppressor is surprisingly small.

Neither service entrance or plug-in suppressors work by absorbing the
surge energy. But in the process of protecting, some energy is absorbed.

--
bud--

 

[ian field]

<vjp2.at@at.BioStrategist.dot.dot.com> wrote in message
news:htq3ba$a0r$2@reader1.panix.com...

*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

Most commercial telecom kit has MOVs but some high end gear has gas
discharge surge suppressors.

Once in a while I've found answering machines with something resembling a
neon bulb where the line lead connects to the PCB.

 

[Cydrome Leader]

bud-- <remove.budnews@isp.com> wrote:

Cydrome Leader wrote:
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
vjp2.at@at.BioStrategist.dot.dot.com wrote:
*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.

There should already be one inside the phone company's Network
Interface.

This applies to the US-

there are surge and lightning arrestors on phone lines where they enter a residence, and they're
grounded to something good, like a water pipe for instance.

It works great.

Some comments are somewhat specific to the US.

A couple of excellent sources of info on surge protection are:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
from the IEEE, and a much simpler one from the US-NIST
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

With a strong surge current to the earthing electrode, the "ground" for
the building can rise thousands of volts above "absolute" earth
potential. You want power and phone (and cable) wires rise together.
That requires a short ground wire from the telephone entrance protector
to the earthing system at the power service.


Now if lightning surges hit your power then what happens?

a cheapo-garbage "surge protector" like a power strip or the like will use MOVs to short out line
to neutral or even line to ground.

What happens if you throw a short across line to ground and can somehow clamp it to 600 volts or
whatever? The numbers are made up, but concept is the same.

well, your ground ends up at 300 volts above actual earth ground where that device is located. This
assumes your ground has the same impedance as the current carrying conductors.

So now your computer isn't really grounded, and floating at a potential way off what the phone like
is at, which worst case is being protected to a really solid ground, and not hundreds of feet or
wiring in your walls or whatever.

This is what blows up stuff like modems or devices that sit between your outlets and a phone line.

If you RTFM, any competent plug-in suppressor manufacturer should tell
you the phone wires have to go through the suppressor along with the
power wires. The voltage on all wires is clamped to the ground at the
suppressor. The voltage between the wires to the protected equipment is
safe for the protected equipment. All interconnected equipment needs to
be connected to the same suppressor, or external wires, like cable need
to go through the suppressor. This is clearly explained in the IEEE
guide starting pdf page 40, and shown in the examples at the end.
Plug-in suppressors work primarily by clamping, not earthing.


The best move is to install a service entrance surge supressor. They'll clamp surges at the best
ground you've got, with the lowest possible impedance, and at your ground/nuetral bonding point not
at your load where any attempts to do so are pretty useless across the extra fraction of an ohm.

Service panel suppressors are a real good idea. I would particularly use
one in high risk areas like Florida.

But from the NIST guide:
"Q - Will a surge protector installed at the service entrance be
sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances
[electronic equipment], No for two-link appliances [equipment connected
to power AND phone or cable or....]. Since most homes today have some
kind of two-link appliances, the prudent answer to the question would be
NO - but that does not mean that a surge protector installed at the
service entrance is useless."

The NIST guide suggests most damage results from high voltage between
power and phone/cable wires. A service entrance suppressor does not, by
itself, limit that voltage.


You can easily test the resistance of your wiring at home too, and at the same time actually test
if your ground is solid.

connect some large resistive loads like halogen lamps, hairdryer, toaster oven or whatever at and
outlet. Measure the voltage drop when it's on. Break out the suicide cables and test that same
device using line to ground.

Depending on how your place is wired, you may find that under an actual load, your ground is really
awful. A volt meter won't pick crappy ground connections unless you are actually running real
current through it, so just reading 120 across hot and ground and saying "looks good" really
doesn't count.

May well be worthwhile. But even with a good earth connection the
building ground can rise thousands of volts.


Trying to suppress a surge with a $4 power strip connected though 5 junction boxes connected with
BX cable can really just be a big joke.

Neither the IEEE or NIST agree. Both guides say plug-in suppressors,
used correctly, are effective. Plug-in suppressors with very high
ratings are readily and cheaply available. In the US you should only buy
suppressors listed under UL1449. UL tests include a testing to at least
a minimum floor of protection. UPSs with surge protection should also
have UL1449 listing.

The lab NIST uses is not the typical home people live in.

Have you opened a "surge supressor" that the average person owns? It's
really surprising more don't catch on fire with no surges.

the construction quality tends to really really suck.

Even "name brand" items from tripp-lite are utter pieces of crap for the
most part. I've seen those catch fire, and these were made in USA ones.

I don't use or trust cheap-o power strips, at all, anywhere.

 

[bud--]

Cydrome Leader wrote:

bud-- <remove.budnews@isp.com> wrote:
Cydrome Leader wrote:
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
vjp2.at@at.BioStrategist.dot.dot.com wrote:
*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.
There should already be one inside the phone company's Network
Interface.
This applies to the US-

there are surge and lightning arrestors on phone lines where they enter a residence, and they're
grounded to something good, like a water pipe for instance.

It works great.
Some comments are somewhat specific to the US.

A couple of excellent sources of info on surge protection are:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
from the IEEE, and a much simpler one from the US-NIST
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

With a strong surge current to the earthing electrode, the "ground" for
the building can rise thousands of volts above "absolute" earth
potential. You want power and phone (and cable) wires rise together.
That requires a short ground wire from the telephone entrance protector
to the earthing system at the power service.

Now if lightning surges hit your power then what happens?

a cheapo-garbage "surge protector" like a power strip or the like will use MOVs to short out line
to neutral or even line to ground.

What happens if you throw a short across line to ground and can somehow clamp it to 600 volts or
whatever? The numbers are made up, but concept is the same.

well, your ground ends up at 300 volts above actual earth ground where that device is located. This
assumes your ground has the same impedance as the current carrying conductors.

So now your computer isn't really grounded, and floating at a potential way off what the phone like
is at, which worst case is being protected to a really solid ground, and not hundreds of feet or
wiring in your walls or whatever.

This is what blows up stuff like modems or devices that sit between your outlets and a phone line.
If you RTFM, any competent plug-in suppressor manufacturer should tell
you the phone wires have to go through the suppressor along with the
power wires. The voltage on all wires is clamped to the ground at the
suppressor. The voltage between the wires to the protected equipment is
safe for the protected equipment. All interconnected equipment needs to
be connected to the same suppressor, or external wires, like cable need
to go through the suppressor. This is clearly explained in the IEEE
guide starting pdf page 40, and shown in the examples at the end.
Plug-in suppressors work primarily by clamping, not earthing.

The best move is to install a service entrance surge supressor. They'll clamp surges at the best
ground you've got, with the lowest possible impedance, and at your ground/nuetral bonding point not
at your load where any attempts to do so are pretty useless across the extra fraction of an ohm.
Service panel suppressors are a real good idea. I would particularly use
one in high risk areas like Florida.

But from the NIST guide:
"Q - Will a surge protector installed at the service entrance be
sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances
[electronic equipment], No for two-link appliances [equipment connected
to power AND phone or cable or....]. Since most homes today have some
kind of two-link appliances, the prudent answer to the question would be
NO - but that does not mean that a surge protector installed at the
service entrance is useless."

The NIST guide suggests most damage results from high voltage between
power and phone/cable wires. A service entrance suppressor does not, by
itself, limit that voltage.

You can easily test the resistance of your wiring at home too, and at the same time actually test
if your ground is solid.

connect some large resistive loads like halogen lamps, hairdryer, toaster oven or whatever at and
outlet. Measure the voltage drop when it's on. Break out the suicide cables and test that same
device using line to ground.

Depending on how your place is wired, you may find that under an actual load, your ground is really
awful. A volt meter won't pick crappy ground connections unless you are actually running real
current through it, so just reading 120 across hot and ground and saying "looks good" really
doesn't count.
May well be worthwhile. But even with a good earth connection the
building ground can rise thousands of volts.

Trying to suppress a surge with a $4 power strip connected though 5 junction boxes connected with
BX cable can really just be a big joke.
Neither the IEEE or NIST agree. Both guides say plug-in suppressors,
used correctly, are effective. Plug-in suppressors with very high
ratings are readily and cheaply available. In the US you should only buy
suppressors listed under UL1449. UL tests include a testing to at least
a minimum floor of protection. UPSs with surge protection should also
have UL1449 listing.

The lab NIST uses is not the typical home people live in.

I have no idea what you are talking about. The discussion is ordinary
surge suppressors

Have you opened a "surge supressor" that the average person owns? It's
really surprising more don't catch on fire with no surges.

the construction quality tends to really really suck.

Even "name brand" items from tripp-lite are utter pieces of crap for the
most part. I've seen those catch fire, and these were made in USA ones.

I don't use or trust cheap-o power strips, at all, anywhere.

So don't get "cheap-o power strips". I use name brand suppressors with
high ratings.

UL1449 has, since 1998, required thermal discoinnects for overheating
MOVs. If a suppressor is UL1449 listed there is not much probability of
any problem. The author of the NIST guide has written "In fact, the
major cause of [surge suppressor] failures is a temporary overvoltage,
rather than an unusually large surge". TOV is, for example, a
distribution wire falling onto the secondary wires that go to your house.

--
bud--

 

[Cydrome Leader]

bud-- <remove.budnews@isp.com> wrote:

Cydrome Leader wrote:
bud-- <remove.budnews@isp.com> wrote:
Cydrome Leader wrote:
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
vjp2.at@at.BioStrategist.dot.dot.com wrote:
*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.
There should already be one inside the phone company's Network
Interface.
This applies to the US-

there are surge and lightning arrestors on phone lines where they enter a residence, and they're
grounded to something good, like a water pipe for instance.

It works great.
Some comments are somewhat specific to the US.

A couple of excellent sources of info on surge protection are:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
from the IEEE, and a much simpler one from the US-NIST
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

With a strong surge current to the earthing electrode, the "ground" for
the building can rise thousands of volts above "absolute" earth
potential. You want power and phone (and cable) wires rise together.
That requires a short ground wire from the telephone entrance protector
to the earthing system at the power service.

Now if lightning surges hit your power then what happens?

a cheapo-garbage "surge protector" like a power strip or the like will use MOVs to short out line
to neutral or even line to ground.

What happens if you throw a short across line to ground and can somehow clamp it to 600 volts or
whatever? The numbers are made up, but concept is the same.

well, your ground ends up at 300 volts above actual earth ground where that device is located. This
assumes your ground has the same impedance as the current carrying conductors.

So now your computer isn't really grounded, and floating at a potential way off what the phone like
is at, which worst case is being protected to a really solid ground, and not hundreds of feet or
wiring in your walls or whatever.

This is what blows up stuff like modems or devices that sit between your outlets and a phone line.
If you RTFM, any competent plug-in suppressor manufacturer should tell
you the phone wires have to go through the suppressor along with the
power wires. The voltage on all wires is clamped to the ground at the
suppressor. The voltage between the wires to the protected equipment is
safe for the protected equipment. All interconnected equipment needs to
be connected to the same suppressor, or external wires, like cable need
to go through the suppressor. This is clearly explained in the IEEE
guide starting pdf page 40, and shown in the examples at the end.
Plug-in suppressors work primarily by clamping, not earthing.

The best move is to install a service entrance surge supressor. They'll clamp surges at the best
ground you've got, with the lowest possible impedance, and at your ground/nuetral bonding point not
at your load where any attempts to do so are pretty useless across the extra fraction of an ohm.
Service panel suppressors are a real good idea. I would particularly use
one in high risk areas like Florida.

But from the NIST guide:
"Q - Will a surge protector installed at the service entrance be
sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances
[electronic equipment], No for two-link appliances [equipment connected
to power AND phone or cable or....]. Since most homes today have some
kind of two-link appliances, the prudent answer to the question would be
NO - but that does not mean that a surge protector installed at the
service entrance is useless."

The NIST guide suggests most damage results from high voltage between
power and phone/cable wires. A service entrance suppressor does not, by
itself, limit that voltage.

You can easily test the resistance of your wiring at home too, and at the same time actually test
if your ground is solid.

connect some large resistive loads like halogen lamps, hairdryer, toaster oven or whatever at and
outlet. Measure the voltage drop when it's on. Break out the suicide cables and test that same
device using line to ground.

Depending on how your place is wired, you may find that under an actual load, your ground is really
awful. A volt meter won't pick crappy ground connections unless you are actually running real
current through it, so just reading 120 across hot and ground and saying "looks good" really
doesn't count.
May well be worthwhile. But even with a good earth connection the
building ground can rise thousands of volts.

Trying to suppress a surge with a $4 power strip connected though 5 junction boxes connected with
BX cable can really just be a big joke.
Neither the IEEE or NIST agree. Both guides say plug-in suppressors,
used correctly, are effective. Plug-in suppressors with very high
ratings are readily and cheaply available. In the US you should only buy
suppressors listed under UL1449. UL tests include a testing to at least
a minimum floor of protection. UPSs with surge protection should also
have UL1449 listing.

The lab NIST uses is not the typical home people live in.

I have no idea what you are talking about. The discussion is ordinary
surge suppressors

yes, ordinary surge surpressors. go to the store, pick one up and tell me
what you find inside of it.

I'd be pleased to counter with the CPSC recall notice.

Have you opened a "surge supressor" that the average person owns? It's
really surprising more don't catch on fire with no surges.

the construction quality tends to really really suck.

Even "name brand" items from tripp-lite are utter pieces of crap for the
most part. I've seen those catch fire, and these were made in USA ones.

I don't use or trust cheap-o power strips, at all, anywhere.

So don't get "cheap-o power strips". I use name brand suppressors with
high ratings.

UL1449 has, since 1998, required thermal discoinnects for overheating
MOVs. If a suppressor is UL1449 listed there is not much probability of
any problem. The author of the NIST guide has written "In fact, the
major cause of [surge suppressor] failures is a temporary overvoltage,
rather than an unusually large surge". TOV is, for example, a
distribution wire falling onto the secondary wires that go to your house.

Again, if you really trust any UL markings on a power strip, go for it.

You do relized that UL doesn't even test most stuff, they sell stickers.
That's the business model. If you want to get more technical, they're
really a licensing company.

they have nothing at all to do with safety, at all, any more than iso 9001
has anything to do with quality.

It's possible you have some decent surge protectors, but you're 0.01% of
the market.

 

[bud--]

Cydrome Leader wrote:

bud-- <remove.budnews@isp.com> wrote:
Cydrome Leader wrote:
bud-- <remove.budnews@isp.com> wrote:
Cydrome Leader wrote:
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
vjp2.at@at.BioStrategist.dot.dot.com wrote:
*+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
*+-ground and from one leg to the other. I guess that's a "delta" config.

Do surge supressors exist for two-line phone connections?

WOuld it make sence to put a surge suppressor (what kind?) on my
incoming phone line? Neighbors have complained of fried modems, but
curiously I don't remember anyone ever telling mtheir computer got fried.
There should already be one inside the phone company's Network
Interface.
This applies to the US-

there are surge and lightning arrestors on phone lines where they enter a residence, and they're
grounded to something good, like a water pipe for instance.

It works great.
Some comments are somewhat specific to the US.

A couple of excellent sources of info on surge protection are:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
from the IEEE, and a much simpler one from the US-NIST
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

With a strong surge current to the earthing electrode, the "ground" for
the building can rise thousands of volts above "absolute" earth
potential. You want power and phone (and cable) wires rise together.
That requires a short ground wire from the telephone entrance protector
to the earthing system at the power service.

Now if lightning surges hit your power then what happens?

a cheapo-garbage "surge protector" like a power strip or the like will use MOVs to short out line
to neutral or even line to ground.

What happens if you throw a short across line to ground and can somehow clamp it to 600 volts or
whatever? The numbers are made up, but concept is the same.

well, your ground ends up at 300 volts above actual earth ground where that device is located. This
assumes your ground has the same impedance as the current carrying conductors.

So now your computer isn't really grounded, and floating at a potential way off what the phone like
is at, which worst case is being protected to a really solid ground, and not hundreds of feet or
wiring in your walls or whatever.

This is what blows up stuff like modems or devices that sit between your outlets and a phone line.
If you RTFM, any competent plug-in suppressor manufacturer should tell
you the phone wires have to go through the suppressor along with the
power wires. The voltage on all wires is clamped to the ground at the
suppressor. The voltage between the wires to the protected equipment is
safe for the protected equipment. All interconnected equipment needs to
be connected to the same suppressor, or external wires, like cable need
to go through the suppressor. This is clearly explained in the IEEE
guide starting pdf page 40, and shown in the examples at the end.
Plug-in suppressors work primarily by clamping, not earthing.

The best move is to install a service entrance surge supressor. They'll clamp surges at the best
ground you've got, with the lowest possible impedance, and at your ground/nuetral bonding point not
at your load where any attempts to do so are pretty useless across the extra fraction of an ohm.
Service panel suppressors are a real good idea. I would particularly use
one in high risk areas like Florida.

But from the NIST guide:
"Q - Will a surge protector installed at the service entrance be
sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances
[electronic equipment], No for two-link appliances [equipment connected
to power AND phone or cable or....]. Since most homes today have some
kind of two-link appliances, the prudent answer to the question would be
NO - but that does not mean that a surge protector installed at the
service entrance is useless."

The NIST guide suggests most damage results from high voltage between
power and phone/cable wires. A service entrance suppressor does not, by
itself, limit that voltage.

You can easily test the resistance of your wiring at home too, and at the same time actually test
if your ground is solid.

connect some large resistive loads like halogen lamps, hairdryer, toaster oven or whatever at and
outlet. Measure the voltage drop when it's on. Break out the suicide cables and test that same
device using line to ground.

Depending on how your place is wired, you may find that under an actual load, your ground is really
awful. A volt meter won't pick crappy ground connections unless you are actually running real
current through it, so just reading 120 across hot and ground and saying "looks good" really
doesn't count.
May well be worthwhile. But even with a good earth connection the
building ground can rise thousands of volts.

Trying to suppress a surge with a $4 power strip connected though 5 junction boxes connected with
BX cable can really just be a big joke.
Neither the IEEE or NIST agree. Both guides say plug-in suppressors,
used correctly, are effective. Plug-in suppressors with very high
ratings are readily and cheaply available. In the US you should only buy
suppressors listed under UL1449. UL tests include a testing to at least
a minimum floor of protection. UPSs with surge protection should also
have UL1449 listing.
The lab NIST uses is not the typical home people live in.
I have no idea what you are talking about. The discussion is ordinary
surge suppressors

yes, ordinary surge surpressors. go to the store, pick one up and tell me
what you find inside of it.

I'd be pleased to counter with the CPSC recall notice.

Have you opened a "surge supressor" that the average person owns? It's
really surprising more don't catch on fire with no surges.

the construction quality tends to really really suck.

Even "name brand" items from tripp-lite are utter pieces of crap for the
most part. I've seen those catch fire, and these were made in USA ones.

I don't use or trust cheap-o power strips, at all, anywhere.
So don't get "cheap-o power strips". I use name brand suppressors with
high ratings.

UL1449 has, since 1998, required thermal discoinnects for overheating
MOVs. If a suppressor is UL1449 listed there is not much probability of
any problem. The author of the NIST guide has written "In fact, the
major cause of [surge suppressor] failures is a temporary overvoltage,
rather than an unusually large surge". TOV is, for example, a
distribution wire falling onto the secondary wires that go to your house.

Again, if you really trust any UL markings on a power strip, go for it.

You do relized that UL doesn't even test most stuff, they sell stickers.
That's the business model. If you want to get more technical, they're
really a licensing company.

Complete nonsense.

In Europe equipment is mostly self-certified that it meets a standard.

UL tests almost all equipment it lists.
http://en.wikipedia.org/wiki/Underwriters_Laboratories
"the UL Mark requires independent third-party certification from UL"

Some equipment, like TVs are tested to fail safely - it is not practical
to test whether they work.

Much of the UL listed equipment - fuses, circuit breakers, switches, ...
- are tested to comply with a standard that requires “fitness for a
given use” and “service life”.Ordinary wall switches used in power
wiring are tested by UL to remain functional after 30,000 operations at
or above their current and voltage rating. (The test is a lot more
involved than that.)

For surge suppressors, under UL1449 suppressors are tested by UL for
let-through voltage under specified conditions followed by a series of
20 surges followed by a let-through voltage test again. If the second
let-through voltage dropped significantly the MOVs are deteriorating. A
suppressor has to be functional through all these tests. Further tests
are of a nature that the suppressor might fail. It must fail safely. As
in my last post, overheating MOVs must be disconnected safely.

Incidentally, I was the technical end of a UL panel shop.

they have nothing at all to do with safety, at all, any more than iso 9001
has anything to do with quality.

UL listing of electrical equipment has everything to do with safety.

It's possible you have some decent surge protectors, but you're 0.01% of
the market.

UL1449 listed suppressors have been tested to pass at least a minimum
floor of protection. Anyone can buy well known name brands and get
suppressors with high ratings like I do.

Francois Martzloff was the surge expert at the US-NIST and wrote the
NIST guide. He also has many published papers on surges. I have included
some of his information in previous posts.

In one of his papers Martzloff has written "in fact, the major cause of
[surge suppressor] failures is a temporary overvoltage, rather than an
unusually large surge". TOV is, for instance, a distribution wire
dropping onto the wires that go to your house. (This is, of course, not
a surge.)

Martzloff also suggests in the NIST guide that most equipment damage is
from high voltage between power and cable/phone wires. (This is
illustrated in the IEEE guide starting pdf page 40.)

The IEEE is the largest association of electrical and electronic
engineers in the US. The IEEE guide (a link was provided) was written by
the IEEE committee that covers surge protection devices. The IEEE guide
says plug-in suppressors are effective. The only 2 examples of
protection in the IEEE guide use plug-in suppressors.

Similarly, surge expert Martzloff says in the NIST guide (link provided)
that plug-in suppressors are effective.

Where is your source that says otherwise.

--
bud--