Maker Pro
Maker Pro

Why do the red lighted switches on surge suppressors eventually begin flashing?

N

N. Thornton

Jan 1, 1970
0
From: John Doe ([email protected])
[email protected] (N. Thornton) wrote
John Doe <[email protected]> wrote in message
<snipped an invitation to a mental circle jerk>

what does that mean? If you want to be offensive to those who are
taking their time to wise you up you wont learn much.

I am reading this thread and I don't see any links to laboratory tests
which provide evidence of your claim surge supressors are a waste of
money.

you dont need a lab test to prove that tomatoes dont make good cricket
balls. The case with surge suppressors is about as elementary. The
obvious way to judge the question is to ask the experts, which you are
now doing. Perhaps if you'd paid one of us to write this you'd then
believe it.

You can always do a quick search on the names here to find out what
experience and qualifications people have.

My research turns up the opposite.

I already explained the motivations. You already said you could be
baffled with bullshit. The conclusion should be obvious.

But you have no idea where your proof might be.

Yes I have. You appear unclear on this.

So you cannot point to any laboratory tests, let alone anything done by
reliable sources,

A group of electronics experts is an unreliable source? Who do you
want your information from, a disco diva?

which substantiates the sensational claim a Tripp-Lite
top of the line surge suppressor (the one I pointed you to) is a waste of
money.

I gave you the theory, youve heard from others well qualified and
experienced in the field too.

But perhaps you know better, perhaps you understand the theory, and
have enough experience to be able to evaluate some of the technical
claims, and do understand the issues with the word 'surge'. Perhaps
you can accurately evaluate financially motivated test results and
understand the business principles behind it all. But so far I've seen
evidence that indicates the opposite in each case.



Now we come onto another point.

"Protection modes: Includes full normal mode (H-N) and common mode
(N-G / H-G) line surge suppression"

So this one does include components offering a limited amount of
common mode suppression. I'll leave it to someone else to explain why
this still will have limited effect.

I'll just add that a million volt lightining strike can blow resistive
loads clean apart, turn them to charcoal, or vapourise them. So whats
it going to do to a 50 cent MOV suppressor the size of a peanut? MOV
rating: 2350 joules, lightning: what?


"AC suppression components used:
Metal oxide varistors, toroidal balanced chokes, ferrite rod-core
inductors and VHF capacitors."

those things are in computer supplies already.


"Network grade surge suppression rated at 2350 joules / 97,000 amps "

Some of us actually know what would happen to it if one put 6000A
through 15A flex, let alone 97,000. Suggested seach words include
cable, wall, explode, channel.


Regards, NT
 
T

Tim Shoppa

Jan 1, 1970
0
John Doe said:
After some more research, I figure the off-topic troll is motivated by
either the fact some do not know buildings in the United States are
shielded from common mode transients, or this is a game.

You mean that single wire running from neutral at the fuse panel,
snaking about 60 or 70 feet to where the cold water pipe enters the
building? Oh, yeah, don't forget that this connection hasn't been
checked or tightened in 40 years, that it has three layers of paint
at the only important junction, and probably got cut up by a roto-
tiller.

Oh, yeah, there's a ground rod on the other side of the house for
the telco demarc and where the cable TV comes in. But that has
four layers of paint over it, which is probably a good thing because
in the event of a nearby lightning strike the ground bounce would
be sure to fry everything near the TV if there *was* a good connection.

I admit, the NEC is much better today, requiring a ground rod at the
entrance in addition to a wire to the cold water pipe, and there is
a nominal (AFAICT completely ignored) requirement that the telco and cable
TV entrances be bonded to the ground at the AC entrance, but there still
is zero requirement nationally for whole-house surge protection.

Tim.
 
J

John Doe

Jan 1, 1970
0
John Woodgate said:
Go back through the group archives and look for the extensive
explanations given by W Thom.

Some folks love to take a Usenet group for a ride.

http://groups.google.com/groups?hl=...F-8&[email protected]&rnum=9

"Surges created by refrigerators, et al are urban myth"

"Surges occur typically once every eight years."
I almost feel bad about quoting that.
Briefly, if you can understand something rather simple, the MOVs in
the device attenuate differential-mode surges by applying a low
impedance between the supply lines. This works, because the
connections are very short and have low resistance and inductance.
However, to attenuate common-mode surges, which are far more prevalent
than differential-mode surges

in Europe
the MOVs need to be between the lines and
ground. There may well be such MOVs in your device. BUT the 'ground' is
at least 12 feet of wire from even the ground in your wall-socket, and
that is another stretch of wire from the ground reference of the surge.
Just that 12 ft of wire has about 6 uH of inductance, as well as some
resistance. This represents a large impedance at the high frequencies
present in the surge and *seriously* compromises the attenuating effect
of the MOVs. The impedance of the wiring from the wall socket to
wherever the ground of the surge source is represents a further
impedance limiting the attenuation.

There IS a situation where differential-mode surges may have little or
no effect on the equipment served by the surge-limiting device. But in
general, you can't be sure that you have that situation (basically, that
there is NO other path to ground whatsoever from anywhere in the total
equipment set-up other than the power cord connected to the surge
limiter). If you DO have it, then when the surge occurs, all the
equipment, including all exposed metal parts, carries the full surge
voltage relative to ground, so be sure you are not touching it when a
surge occurs.

Whether your device is a waste of money or not is for YOU to decide. I
make no such assertion. You may consider that the insurance scheme
associated with it is worth having even if there are doubts about some
aspects of its performance.

I wonder whether any manufacturer of these devices has put products
through the European EMC common-mode surge test (IEC 61000-4-5, Figure 6
[1]) and is prepared to publish the results, including the length of the
cable used.

I appreciate that.

I have diligently attempted to avoid entities which manufacture or sell
surge and noise suppressors.

http://millimeter.com/ar/avinstall_shelter_storm/

"Surges caused by utility switching and natural phenomena — for the most
part, lightning — occur in the normal mode. They have to because of the
binding together of neutral and ground at the service entrance."

"European wiring practice is more likely to result in common mode
surges"

http://www.totse.com/en/technology/computer_technology/surge.html

"Surges originating from outside your building are always normal mode,
since neutral and safety ground lines are tied together to an earth
ground at the service entrance."

http://www.erico.com/erico_public/general_info/CRITECTNCR016.asp

"Note that although most lightning impulses are common mode at the point
of coupling, these will be converted to a differential mode at the
service entrance by the presence of the neutral-ground bond."

http://www.tao.com/zero/glossary.html

"For safety reasons, electrical systems in the USA have a wire connected
to earth ground at the service entrance."

http://www.zerosurge.com/HTML/mode2.html

"All these ungrounded applications [in Europe] have vastly greater
common mode surge exposure than the grounded 120 Volt systems in the
USA"

I think that one sells stuff.

It explains why...
....the devices are so popular.
....Tripp Lite insures surge and noise suppressors in the United States &
Canada only.
....I cannot find anything on the Internet which supports the claim surge
and noise suppressors are worthless. That one is really obvious to me.
Here in the US, anyone who thinks themselves independent would be all
over it.
....MOVs wear out, unless MOVs are self destructing. In other words, they
are taking hits something else would take if they weren't there.
 
J

John Doe

Jan 1, 1970
0
Really? How do they do that? Why then does the US version of IEC
61000-4-5 call for a more severe test (lower source resistance) for
*equipment* than the International Standard? If the equipment is never
exposed to surges, there is no justification for any test at all.

http://groups.google.com/[email protected]&rnum=4
John said:
Except at a service entrance, but if the neutral is properly grounded
there, no common-mode surge can exist at that point unless it is due to
a very close lighting strike, causing local ground-lift, "

Out.
 
G

Georg Acher

Jan 1, 1970
0
|> "All these ungrounded applications [in Europe] have vastly greater
|> common mode surge exposure than the grounded 120 Volt systems in the
|> USA"

Well, Europe is not one country with only one regulation. At least in Germany
(and Austria) the connection of the green-yellow earth wire to earth ground in
the house is standard. Older installations (<1975 or so) share a common earth and
neutral wire, but this one is usually also connected to "real earth" somewhere in
the house. Other countries may have similar or totally different wirings ;-)
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Georg Acher <[email protected]>
wrote (in <[email protected]>) about 'Surge
suppression, USA versus Europe (was Re: Why do the red lighted switches
Well, Europe is not one country with only one regulation. At least in
Germany (and Austria) the connection of the green-yellow earth wire to
earth ground in the house is standard.

But it doesn't eliminate common-mode surges unless:

a) the inductance of the neutral to local earth is very low, and

b) the inductance of the earth path to the source of the surge is also
very low.
Older installations (<1975 or so)
share a common earth and neutral wire, but this one is usually also
connected to "real earth" somewhere in the house.

This gives a low-inductance path to the earth at the supply transformer,
but the local path still needs to have a much lower inductance than is
required for normal safety reasons. And the surge may originate
downstream of the house, so that the relevant inductance is that of the
intervening supply cable run and is not very low.
Other countries may
have similar or totally different wirings ;-)

Yes: in UK the neutral is *not allowed* to be earthed locally.
 
J

John Woodgate

Jan 1, 1970
0
(in <[email protected]>) about 'Why do the
red lighted switches on surge suppressors eventually begin flashing?',
http://groups.google.com/groups?q=neutral+ground+"service+entrance"+group:sc
i.electronics.design&hl=en&lr=lang_en&ie=UTF-8&oe=UTF-8&scoring=d&selm=epZCsdA3f
Lh7EwNp%40jmwa.demon.co.uk&rnum=4


Out.

Yes, you should retire at that point. See that word 'properly'? That's
what I've been trying to convince you about. 'Properly' = very low
impedance. Very rarely found.
 
J

John Doe

Jan 1, 1970
0
My nibble of Electronics Design Automation years ago makes this group
somewhat special to me. I appreciate the on-topic answers and learned
some potentially useful stuff in the off-topic argument. Thanks. Bye.
 
N

N. Thornton

Jan 1, 1970
0
John Doe said:
Some folks love to take a Usenet group for a ride.

http://groups.google.com/groups?hl=...F-8&[email protected]&rnum=9

"Surges created by refrigerators, et al are urban myth"

"Surges occur typically once every eight years."
I almost feel bad about quoting that.

these quotes are meaningless unless you define what you mean by surges
first, something you seem to have avoided. One could say a light bulb
causes a surge, a direct lightning strike causes a surge, switching
the tv on causes a surge - but of what magnitude, of what type, and of
what consequence?

I have diligently attempted to avoid entities which manufacture or sell
surge and noise suppressors.

http://millimeter.com/ar/avinstall_shelter_storm/

"Surges caused by utility switching and natural phenomena ? for the most
part, lightning ? occur in the normal mode. They have to because of the
binding together of neutral and ground at the service entrance."

"European wiring practice is more likely to result in common mode
surges"

http://www.totse.com/en/technology/computer_technology/surge.html

"Surges originating from outside your building are always normal mode,
since neutral and safety ground lines are tied together to an earth
ground at the service entrance."

http://www.erico.com/erico_public/general_info/CRITECTNCR016.asp

"Note that although most lightning impulses are common mode at the point
of coupling, these will be converted to a differential mode at the
service entrance by the presence of the neutral-ground bond."

http://www.tao.com/zero/glossary.html

"For safety reasons, electrical systems in the USA have a wire connected
to earth ground at the service entrance."

http://www.zerosurge.com/HTML/mode2.html

"All these ungrounded applications [in Europe] have vastly greater
common mode surge exposure than the grounded 120 Volt systems in the
USA"

I think that one sells stuff.


All these seem to assume that earthing is 100% effective, which is a
rash assumption. And that megavolt lightning takes much notice of
cable insulation.

It explains why...
...the devices are so popular.

no, most people dont buy because of technical bulletins, they buy
because of advertising.
...Tripp Lite insures surge and noise suppressors in the United States &
Canada only.
...I cannot find anything on the Internet which supports the claim surge
and noise suppressors are worthless.

I though you'd already quoted similar things, from several sources
here. Please note tho that they are not worthless, as they do have
some valid uses, they generally include a multi-socket
adaptor/extension lead, and they often have an insurance policy, which
actually will pay out in some cases. And if youre running computers on
a small local generator they are indeed wise to have.
That one is really obvious to me.
Here in the US, anyone who thinks themselves independent would be all
over it.

Really. You might want to look up PMPO power ratings then, and the
slating that that gets. Then look up stupidly priced speaker cables,
and so on ad nauseam, and ask yourself why you arent seeing much
journo response to those issues either. You dont seem to have
understood it.

...MOVs wear out, unless MOVs are self destructing. In other words, they
are taking hits something else would take if they weren't there.


I promised myself I would reply any more, but I couldnt resist I
suppose.


Regards, NT
 
T

Tim Shoppa

Jan 1, 1970
0
John Doe said:
Some folks love to take a Usenet group for a ride.

http://groups.google.com/groups?hl=...F-8&[email protected]&rnum=9

"Surges created by refrigerators, et al are urban myth"

Surges generated by large inductive loads are certainly not urban
myth. Start spinning up a large motor, and have a breaker trip in the
process, and you end up with an arc *somewhere*. This is what V = - L dI/dt
means.

In this sense a breaker trip isn't necessarily a fail-safe situation.

The situation of having janitorial staff plug in their floor polishers into
our computer room sockets got so bad that we installed locked-by-key outlet
covers over them all. The cost was tiny compared to the equipment damage
($20000+) and downtime.

A typical household refrigerator compressor isn't nearly as bad as a
floor polisher, but it's still an inductive load.

Tim.
 
Top