AC Power Surge Protection?

[KenO]

A friend recently had her audio system damaged from an AC Power Surge.

Would like to prevent this so Googled using AC Power Surge Protection and found "The Best Surge Protector by Brent Butterworth.
http://thewirecutter.com/reviews/best-surge-protector/

Read link "Surge Protectors ??? (Brickwall, Zero Surge, Furman, SurgeX," http://www.avsforum.com/forum/40-oled-technology-flat-panels-general/1146963-surge-protectors-brickwall-zero-surge-furman-surgex-etc.html

Then did a Forum search and found some very long discussions such as:
Surge Protectors https://groups.google.com/forum/#!searchin/sci.electronics.repair/AC$20Power$20Surge$20Protection%7Csort:relevance/sci.electronics.repair/mkLpyahIKNk/3GvjxW9LrrsJ

Surge protector fuse blown https://groups.google.com/forum/#!searchin/sci.electronics.repair/AC$20Power$20Surge$20Protection%7Csort:relevance/sci.electronics.repair/iUffPhXZsNA/Ay8058Ba46QJ

I do not have a technical background so would be interested in others comments concerning all this.

Would like to use your advice to build a cost effective audio protection system.

Thanks

Ken

[Trevor Wilson]

On 27/05/2015 9:12 AM, KenO wrote:
> A friend recently had her audio system damaged from an AC Power
> Surge.

**How do you know it was a "power surge"? Where did this alleged "power
surge" originate?

**The best way to protect an audio system from "power surges" is to
disconnect the TV antenna during lightning storms, since that is, far
and away, the most common source of "power surges". Mains bourne "power
surges" are incredibly rare events and almost nothing available off the
shelf can deal with the energies involved.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

[Phil Allison]

KenO wrote:
>
> A friend recently had her audio system damaged from an AC Power Surge.
>

** AC power voltage surges damaging audio gear are so rare that I cannot accept it as true without convincing evidence.

The DC power supply inside each piece of audio gear usually contains a transformer, rectifier and filter electros - a combination that eliminates AC voltage spikes/surges better than anything you can possibly buy or build.

OTOH, the term "power surge" is regularly used to explain away sudden failures in almost any electronic device - when the real cause is simply a bad component.


.... Phil

[N_Cook]

Well you survived long enough to provide this homicidal info.
You disconnect TV aerials BEFORE lightening storms.

[Tim R]

On Wednesday, May 27, 2015 at 3:28:50 AM UTC-4, N_Cook wrote:
> > **The best way to protect an audio system from "power surges" is to
> > disconnect the TV antenna during lightning storms, since that is, far
> > and away, the most common source of "power surges". Mains bourne "power
> > surges" are incredibly rare events and almost nothing available off the
> > shelf can deal with the energies involved.
> >
> >
>
> Well you survived long enough to provide this homicidal info.
> You disconnect TV aerials BEFORE lightening storms.

Yeah, I always wait until between flashes to climb the mast and disconnect the antenna.

[Baron]

Phil Allison prodded the keyboard with:

+1
--
Best Regards:
Baron.

[Gareth Magennis]

"Baron" wrote in message news:mk4gc9$7fm$1...@dont-email.me...

Many years ago I was working for a PA Hire company. One day we had a real
"power surge".
All the lights started getting really bright, then normal again, then back
to really bright etc. It was quite a weird experience.
I seem to recall we hit the emergency Power Off button in the warehouse
after measuring the mains outlets being well above 300v.

Most of the office equipment got fried - photocopier, printer etc. but no
humans or any of the audio gear were hurt.

We called in the electricity supply company, who (they said) discovered a
bad Mains Intake Neutral connection.
They paid compensation for all the fried gear, and we all saw the funny
side.




Gareth.

[Trevor Wilson]

**OUCH! You are, of course, correct.

[Ron D.]

I'll point you here: http://www.gryphon-inc.com/White_Papers.html

I've had extreme success with Powervar/ONEAC products. Like 25 years on a very critical computer system. The only failures were mechanical like fans and floppy drives. The hard drive was on 15 years before the system was upgraded. It did cost about $1K USD in the 80's for about 1000 W. Later, two other systems got the same technology.

Usually, the warranty and the sales receipt helps a lot. Less critical systems got the tripp-lite isobar which oneac doesn;t like either. I did see an ISOBAR fry and Trip-lite replaced the connected equipment.

I had an APC surge suppressor (given to me) and it's is supposed to be replaced because it causes fires. I think it's been close to 3 months now and no replacement APC. Furthermore, that APC did not protect itself. Oh maybe it did? It prevent itself from frying by blowing a thermal fuse and passing the surge to the equipment and lighting a LED.

[Ron D.]

A whole house suppressor would not be a bad idea either.

[Trevor Wilson]

**For what purpose? An event that is so incredibly rare that the average
person won't see one in several life-times.

The whole 'surge suppressor' industry is a con. It is the only
significant profit area left for retailers of domestic electronic
equipment. Profit margins run to several hundred percent. That said: A
whole house suppressor is a reasonably economical solution to an almost
non-existent problem. It must be fitted by a qualified electrical
contractor.

FWIW: The only time I have ever heard of a significant surge on a power
line, was at my previous home, before I moved in. A 5kV railway bearer
fell across the 240VAC mains supply. This was in the early 1970s. It
wiped out the electronic and electrical equipment for several blocks. I
doubt that anything that can be purchased retail can protect against
such a rare event.

[gregz]

Trevor Wilson <tre...@SPAMBLOCKrageaudio.com.au> wrote:
> On 28/05/2015 12:21 PM, Ron D. wrote:
>> On Wednesday, May 27, 2015 at 5:16:28 PM UTC-4, Ron D. wrote:
>>> I'll point you here: http://www.gryphon-inc.com/White_Papers.html
>>>
>>> I've had extreme success with Powervar/ONEAC products. Like 25
>>> years on a very critical computer system. The only failures were
>>> mechanical like fans and floppy drives. The hard drive was on 15
>>> years before the system was upgraded. It did cost about $1K USD in
>>> the 80's for about 1000 W. Later, two other systems got the same
>>> technology.
>>>
>>> Usually, the warranty and the sales receipt helps a lot. Less
>>> critical systems got the tripp-lite isobar which oneac doesn;t like
>>> either. I did see an ISOBAR fry and Trip-lite replaced the
>>> connected equipment.
>>>
>>> I had an APC surge suppressor (given to me) and it's is supposed to
>>> be replaced because it causes fires. I think it's been close to 3
>>> months now and no replacement APC. Furthermore, that APC did not
>>> protect itself. Oh maybe it did? It prevent itself from frying by
>>> blowing a thermal fuse and passing the surge to the equipment and
>>> lighting a LED.
>>
>> A whole house suppressor would not be a bad idea either.
>>
>
> **For what purpose? An event that is so incredibly rare that the average
> person won't see one in several life-times.

Some time after installing a whole house suppressor, we had an instance
where power was going off and on during a storm. A loud crack downstairs,
found suppressor blown. I replaced that one but have not found any other
local supressor faulted that I know of. The model has a lower trip point
voltage to other models I've seen. When I moved in this house the power
company said a surge device was installed and if I wanted to pay monthly
charge. I sad no, but never knew of anybody removing it from the meter,
which would require power interruption.
These things will not help a direct lightning hit.

Greg

[Mark Justice]

Not in Florida.
I was checking a Sunbeam frying pan to see if it worked plugging it in in
the garage when kbang.
Tossed across the garage I went to see what was damaged, besides me.

Several outlets in the house had carbon scarring around them, the
splitter to the color T.V. was mostly vaporized with just a small piece
of circuit board with the ghostly outlines of parts no longer of the
Earth.

The color T.V. worked only as black and white for some weeks when the
color decided to return.
Outside a bruise or three and a short case of the stunned shakes I was
unhurt.

Not unusual around these parts to lose equipment due to surges coming in
through the line, YMMV

[John-Del]

On Thursday, May 28, 2015 at 1:24:00 AM UTC-4, Trevor Wilson wrote:

> >
> > A whole house suppressor would not be a bad idea either.
> >
>
> **For what purpose? An event that is so incredibly rare that the average
> person won't see one in several life-times.
>

Every summer we see TVs come in with blown bridge rectifiers and vaporized pc traces. As long as it's confined to the primary side of the power supply it's no big deal. Any fine damaged traces on the secondary means we go no further. My own TV (1991 RCA CTC169) got whacked when I was watching it. Blew everything from the SMPS primary back including circuit traces, and was left with two other issues (odd system control vol/mute function and loss of AV switching).

[Tim R]

Is there any difference in the robustness of the old tube TV versus the flat screen, when it comes to lightning etc.?

[John-Del]

On Thursday, May 28, 2015 at 8:40:10 AM UTC-4, Tim R wrote:

>
> Is there any difference in the robustness of the old tube TV versus the flat screen, when it comes to lightning etc.?

Only with regard to HDMI ports, which are *very* susceptible to lightning damage. Since the newest generation now does HDMI switching in the main IC which is BGA, damage through the HDMI ports means a new main board. I recommend my customers to use the component inputs when using cable, sat, or IP TV. I haven't seen any damage yet via bluray player.

[bud--]

On 5/26/2015 5:12 PM, KenO wrote:

Excellent information on surges and surge protection is at:
http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf
- "How to protect your house and its contents from lightning: IEEE guide
for surge protection of equipment connected to AC power and
communication circuits" published by the IEEE in 2005 (the IEEE is a
major organization of electrical and electronic engineers).
And also:
http://pml.nist.gov/spd-anthology/files/Surges_happen!.pdf
- "NIST recommended practice guide: Surges Happen!: how to protect the
appliances in your home" published by the US National Institute of
Standards and Technology in 2001

Both guides are from reliable sources.

The IEEE surge guide is more technical.

> A friend recently had her audio system damaged from an AC Power Surge.
>
> Would like to prevent this so Googled using AC Power Surge Protection and found "The Best Surge Protector by Brent Butterworth.
> http://thewirecutter.com/reviews/best-surge-protector/

I wouldn't rely on the testing that was done. There are standard tests
for surge protectors - 600V is not one of them (6,000V is). And I have
no idea if their test is representative of a surge. There is related
information on UL testing in the IEEE surge guide under "2.2.3 Surge
Limiting Voltage"

>
> Read link "Surge Protectors ??? (Brickwall, Zero Surge, Furman, SurgeX," http://www.avsforum.com/forum/40-oled-technology-flat-panels-general/1146963-surge-protectors-brickwall-zero-surge-furman-surgex-etc.html

The vast majority of surge protectors use MOVs as the voltage limiting
element (over 90% according to the IEEE surge guide). These protectors
do not use MOVs. I have not seen them evaluated by a reliable
independent agency, and I would not use them. They, of course, claim to
be better than the MOV based ones. Some of their arguments are downright
stupid.

>
> Then did a Forum search and found some very long discussions such as:
> Surge Protectors https://groups.google.com/forum/#!searchin/sci.electronics.repair/AC$20Power$20Surge$20Protection%7Csort:relevance/sci.electronics.repair/mkLpyahIKNk/3GvjxW9LrrsJ

Westom is an internet nut that googles for "surge" to spread his ideas
about protection. He has joined an astonishing number of forums to
spread his ideas. Some of them are good, some not-so-good, and some are
complete nonsense. Everything he says about plug-in protectors is
complete nonsense. How can you tell? Westom says plug in protectors
don't work. Both the IEEE and NIST guides say they are effective.

I am "bud". I got tired of westom's crap after seeing it on several
Usenet groups I watch over a short period. I have nothing to do with the
surge protection industry other than I am using a couple protectors. A
lot of what I wrote here comes from the IEEE and NIST surge guides

>
> Surge protector fuse blown https://groups.google.com/forum/#!searchin/sci.electronics.repair/AC$20Power$20Surge$20Protection%7Csort:relevance/sci.electronics.repair/iUffPhXZsNA/Ay8058Ba46QJ

w_tom is a name that westom used to use. More nonsense.

I have not read either of these threads.

>
> I do not have a technical background so would be interested in others comments concerning all this.
>
> Would like to use your advice to build a cost effective audio protection system.
>
> Thanks
>
> Ken

If using a plug-in protector all interconnected equipment needs to be
connected to the same protector. External connections, like coax also
must go through the protector. As explained in the IEEE surge guide
(starting page 30) plug-in protectors work primarily by limiting the
voltage from each wire to the ground at the protector. To do that all
wires must go through the protector.

The NIST surge guide suggests most equipment damage is from high voltage
between power and signal (phone, cable,...) wires. Computer and video
equipment is likely more at risk than audio. And it depends on where you
are. Some parts of the US have significant surge exposure. The major
cause of damaging surges is lightning. Normal and abnormal utility
operations can also cause damaging surges.

The author of the NIST surge guide looked at the surge current that
might come in on power wiring (US). The source was a 100,000A lightning
strike to a utility pole adjacent to a house with typical urban overhead
power distribution. Only 5% of strikes are more powerful and this is,
for practical purposes, the worst case. The surge current was 10,000A
per wire. Service panel protectors with much higher ratings are readily
available. High ratings mean long life. A service panel protector is
likely to protect anything connected only to power wiring (most audio
systems?)

The author of the NIST surge guide also investigated how much energy
might be absorbed in a MOV in a plug-in protector. Branch circuits were
10m and longer, and the surge on incoming power wires was up to 10,000A
(wort case, as above). The maximum energy at the MOV was a surprisingly
small 35 joules. In 13 of 15 cases it was 1 joule or less. There are a
couple simple reasons the energy is so low (one of which may be
particular to US wiring). Any UL listed protector in the US will have
ratings higher than that, and much higher ratings are readily available
(as in your first link). Again high ratings mean long life.

(Neither service panel or plug-in protectors protect by absorbing a
surge. They do absorb some energy in the process of protecting. And
protection from a direct strike to a building requires lightning rods.)

In the US, since 1998 UL has required thermal disconnects for
overheating MOVs. (With world markets they are probably included by all
competent manufacturers everywhere.) APC had an engineering error
resulting in a recall.

The IEEE surge guide describes how the protected equipment can be
connected across the MOVs, or be connected across the incoming power
wires. If connected across the MOVs, the protected equipment will be
disconnected on failure. (That is one reason why manufacturers can have
protected equipment warranties.) I think the IEEE surge guide says UL
requires protectors to state if they do not disconnect the protected
load with the MOVs.)

It would be nice if you could compare protectors based on joule rating.
The IEEE surge guide explains that (US) there is not a standard way of
measuring this, so some manufacturers have misleading ratings. Some
other (reliable) manufacturers responded by not including joule ratings.

[Cydrome Leader]

Phil Allison <palli...@gmail.com> wrote:
> KenO wrote:
>>
>> A friend recently had her audio system damaged from an AC Power Surge.
>>
>
> ** AC power voltage surges damaging audio gear are so rare that I cannot accept it as true without convincing evidence.
>
> The DC power supply inside each piece of audio gear usually contains a transformer, rectifier and filter electros - a combination that eliminates AC voltage spikes/surges better than anything you can possibly buy or build.

That may be true if the stereo or whatever is not attached to other
devices. Once you connect things together, damage from power surges starts
to happen.

It's quite common with computer network gear. Interconnected ports fail,
while the main switch chassis or network attached printer or computer
continue to work.

Service entrance surge surpressors protect against this sort of issue.

> OTOH, the term "power surge" is regularly used to explain away sudden failures in almost any electronic device - when the real cause is simply a bad component.

power surges and the damage they cause are very real problems.

FWIW somebod mentioned powervar and Oneac devices, it wasn't clear what
these devices were, but if they were isolation/filter units, they work
great.

Stuff from tripplite is pure junk, had many of their devices catch on
fire, without surges. It was always caused by poor crimps and junky power
switches or bad assembly.

APC power strips are better, never had one self destruct yet.

[Phil Allison]

Cydrome Leader wrote:

> > KenO wrote:
> >>
> >> A friend recently had her audio system damaged from an AC Power Surge.
> >>
> >
> > ** AC power voltage surges damaging audio gear are so rare that I cannot accept it as true without convincing evidence.
> >
> > The DC power supply inside each piece of audio gear usually contains a transformer, rectifier and filter electros - a combination that eliminates AC voltage spikes/surges better than anything you can possibly buy or build.
>
> That may be true if the stereo or whatever is not attached to other
> devices. Once you connect things together, damage from power surges starts
> to happen.

** My comments were intended to exclude the effects of a lightning strikes hitting the ground.

AC supply voltage spikes are normally caused by inductive loads going on and off.

>
> > OTOH, the term "power surge" is regularly used to explain away sudden failures in almost any electronic device - when the real cause is simply a bad component.
>
> power surges and the damage they cause are very real problems.

** If by 'power surge' you actually you mean lightning strike.




... Phil

[Phil Allison]

bud-- wrote:

>
> As explained in the IEEE surge guide
> (starting page 30) plug-in protectors work primarily by limiting the
> voltage from each wire to the ground at the protector.

** Connecting MOVs to ground like that in a *plug-in device* is prohibited on safety grounds under EU and similar regulations as followed in most 230/240 V places - like Australia where I am.

MOVs either have or can develop after some use leakage currents well in excess of the maximum permitted, which is only a milliamp or so for most categories of appliances.

The only components that may be so connected are agency approved " Y caps " with values like 4.7nF - while MOVs and " X caps" always go across the line.



... Phil

[Gareth Magennis]

"Phil Allison" wrote in message
news:85f11b0e-85bd-4d2c...@googlegroups.com...

Slightly OT but .....
In the UK you can buy "surge protected" multi outlet extensions like this:
http://www.amazon.co.uk/Sivitec-Switched-Extension-Protection-Indicator/dp/B00DVHK7IY/ref=sr_1_1?ie=UTF8&qid=1432969032&sr=8-1&keywords=4+gang+surge+protection

Problem is, these can't be tested with a typical PAT Tester, as they fail
the test every time, being as there is circuitry between live and ground.



Gareth.

[Phil Allison]

Gareth Magennis wrote:

> "Phil Allison" wrote in message
> news:85f11b0e-85bd-4d2c...@googlegroups.com...
>
> bud-- wrote:
>
> >
> > As explained in the IEEE surge guide
> > (starting page 30) plug-in protectors work primarily by limiting the
> > voltage from each wire to the ground at the protector.
>
> ** Connecting MOVs to ground like that in a *plug-in device* is prohibited
> on safety grounds under EU and similar regulations as followed in most
> 230/240 V places - like Australia where I am.
>
> MOVs either have or can develop after some use leakage currents well in
> excess of the maximum permitted, which is only a milliamp or so for most
> categories of appliances.
>
> The only components that may be so connected are agency approved " Y caps "
> with values like 4.7nF - while MOVs and " X caps" always go across the
> line.
>
>

> In the UK you can buy "surge protected" multi outlet extensions like this:
> http://www.amazon.co.uk/Sivitec-Switched-Extension-Protection-Indicator/dp/B00DVHK7IY/ref=sr_1_1?ie=UTF8&qid=1432969032&sr=8-1&keywords=4+gang+surge+protection
>
>
> Problem is, these can't be tested with a typical PAT Tester, as they fail
> the test every time, being as there is circuitry between live and ground.

** Really? You read this somewhere on the net, right?

I bet they CAN be tested, passing all the tests is the issue.

FYI:

A customer, who runs a hire business, brought in his "Megger 4DV" PAT tester recently for a check over - so I got to see exactly what it did and how.

Some tests involved normal AC power being applied to the device, others used high voltage DC and another low voltage AC at high current to check earth conductor resistance.

AC leakage current and insulation resistance are the main things checked - the pass /fail threshold was user adjustable to suit the type of appliance under test. Class 1 and class 2 ( double insulated ) appliances follow different rules.

The operator is also expected to carry out a thorough visual inspection too, so needs to be familiar with electrical appliance safety.

If a new product failed one of the tests, that would be VERY alarming and should be reported to the supplier immediately.



... Phil

[Gareth Magennis]

"Phil Allison" wrote in message

news:408a078a-4d5b-4474...@googlegroups.com...

Gareth Magennis wrote:

> "Phil Allison" wrote in message
> news:85f11b0e-85bd-4d2c...@googlegroups.com...
>
> bud-- wrote:
>
> >
> > As explained in the IEEE surge guide
> > (starting page 30) plug-in protectors work primarily by limiting the
> > voltage from each wire to the ground at the protector.
>
> ** Connecting MOVs to ground like that in a *plug-in device* is prohibited
> on safety grounds under EU and similar regulations as followed in most
> 230/240 V places - like Australia where I am.
>
> MOVs either have or can develop after some use leakage currents well in
> excess of the maximum permitted, which is only a milliamp or so for most
> categories of appliances.
>
> The only components that may be so connected are agency approved " Y caps
> "
> with values like 4.7nF - while MOVs and " X caps" always go across the
> line.
>
>
> In the UK you can buy "surge protected" multi outlet extensions like this:
> http://www.amazon.co.uk/Sivitec-Switched-Extension-Protection-Indicator/dp/B00DVHK7IY/ref=sr_1_1?ie=UTF8&qid=1432969032&sr=8-1&keywords=4+gang+surge+protection
>
>
> Problem is, these can't be tested with a typical PAT Tester, as they fail
> the test every time, being as there is circuitry between live and ground.


** Really? You read this somewhere on the net, right?

No, I have a PAT Tester and PAT Test all the sound and lighting equipment
for a music festival.

I was told by an electrician that you have to test these as Class 2, and put
a sticker on them to say so.


Gareth.

[bud--]

I think the US-UL permitted leakage for "appliances" is 0.5mA (which of
course is at 120V).

Standard practice in the US for plug-in protectors is MOVs from H-N,
H-G, N-G. And if signal wires go through the protector, they are limited
to ground also.

One of the reasons the energy at a MOV in a protector is so low (US) is
that at about 6kV there is arc-over between service panel busbars and
the enclosure. This appears to be an intentional feature. (The voltage
across the established arc is hundreds of volts. Since the enclosure is
connected to the earthing system that dumps most of the surge energy to
earth. And a required N-G bond at the service limits the N surge voltage.)

A significant (and likely major) cause of surge damage to equipment is
high voltage between power and signal wires. If MOVs are only connected
H-N and there is a large surge the voltage drop on H & N will likely
increase the voltage between power and signal wires (6kV at the service
would result in about 2kV from the H & N to the 'ground' reference at
the service panel). It then would be inadvisable to use plug-in
protectors on equipment that has both power and signal wires.

The normal failure mode for MOVs is after sufficient energy hits they
start to conduct at lower voltages, eventually conduct at 'normal'
voltages, and go into thermal runaway. Thermal disconnects then
operate(at least in the US). I would think a H-N MOV with 1mA leakage
@230V would be near thermal runaway.

I don't know how surge protection is done down-under. It works here.
Some features here may be from the relatively high exposure to
thunderstorms in parts of the country. They are uncommon or nonexistent
in many parts of the globe.

[Phil Allison]

Gareth Magennis wrote:

> "Phil Allison"
> >

> > ** Connecting MOVs to ground like that in a *plug-in device* is prohibited
> > on safety grounds under EU and similar regulations as followed in most
> > 230/240 V places - like Australia where I am.
> >
> > MOVs either have or can develop after some use leakage currents well in
> > excess of the maximum permitted, which is only a milliamp or so for most
> > categories of appliances.
> >
> > The only components that may be so connected are agency approved " Y caps
> > "
> > with values like 4.7nF - while MOVs and " X caps" always go across the
> > line.
> >
> >
> > In the UK you can buy "surge protected" multi outlet extensions like this:
> > http://www.amazon.co.uk/Sivitec-Switched-Extension-Protection-Indicator/dp/B00DVHK7IY/ref=sr_1_1?ie=UTF8&qid=1432969032&sr=8-1&keywords=4+gang+surge+protection
> >
> >
> > Problem is, these can't be tested with a typical PAT Tester, as they fail
> > the test every time, being as there is circuitry between live and ground.
>
>
> ** Really? You read this somewhere on the net, right?
>
>
> No, I have a PAT Tester and PAT Test all the sound and lighting equipment
> for a music festival.
>
> I was told by an electrician that you have to test these as Class 2, and put
> a sticker on them to say so.

** That is completely insane crap.

He must have been using illegal drugs to say such a thing and you are nuts to believe it.




.... Phil

[Phil Allison]

bud-- wrote:

Phil Allison wrote:

> > ** Connecting MOVs to ground like that in a *plug-in device* is prohibited on safety grounds under EU and similar regulations as followed in most 230/240 V places - like Australia where I am.
> >
> > MOVs either have or can develop after some use leakage currents well in excess of the maximum permitted, which is only a milliamp or so for most categories of appliances.
> >
> > The only components that may be so connected are agency approved " Y caps " with values like 4.7nF - while MOVs and " X caps" always go across the line.
> >
>
>

> Standard practice in the US for plug-in protectors is MOVs from H-N,
> H-G, N-G.

** I really doubt using three MOVs like that is *normal* practice - certainly one never sees it in entertainment electronics or test gear, whether made in the USA or elsewhere.

>
> The normal failure mode for MOVs is after sufficient energy hits they
> start to conduct at lower voltages, eventually conduct at 'normal'
> voltages, and go into thermal runaway.

** The fact that MOVs deteriorate means it is hazardous to have them wired from active to safety ground. Same argument goes for regular metallised film capacitors which also deteriorate when exposed to AC supply voltages - then explode.

> I would think a H-N MOV with 1mA leakage
> @230V would be near thermal runaway.

** Takes at least 10mA to get a typical MOV device hot.



.... Phil

[bud--]

On 5/31/2015 1:14 AM, Phil Allison wrote:
> bud-- wrote:
> Phil Allison wrote:
>
>>> ** Connecting MOVs to ground like that in a *plug-in device* is prohibited on safety grounds under EU and similar regulations as followed in most 230/240 V places - like Australia where I am.
>>>
>>> MOVs either have or can develop after some use leakage currents well in excess of the maximum permitted, which is only a milliamp or so for most categories of appliances.
>>>
>>> The only components that may be so connected are agency approved " Y caps " with values like 4.7nF - while MOVs and " X caps" always go across the line.
>>>
>>
>>
>> Standard practice in the US for plug-in protectors is MOVs from H-N,
>> H-G, N-G.
>
>
> ** I really doubt using three MOVs like that is *normal* practice - certainly one never sees it in entertainment electronics or test gear, whether made in the USA or elsewhere.

Entertainment electronics may have some surge protection but is not
intended to protect against major surges.

As can be seen from the IEEE surge guide, 3 MOVs is absolutely standard
practice in the US.

Because of the additional risks added by having only H-N protection in
plug-in protectors (as in my last post) I suspect 3 MOVs is common
practice elsewhere, H-N only protectors can increase risk, not reduce
it. Gareth does not know what is connected H-G. You do not necessarily
know what the specific requirements are for plug-in protectors elsewhere.

All the packaging protectors come in that I have seen indicate what the
protection is (H-N, H-G, N-G). I suspect it would elsewhere. I am not
interested in looking.

>>
>> The normal failure mode for MOVs is after sufficient energy hits they
>> start to conduct at lower voltages, eventually conduct at 'normal'
>> voltages, and go into thermal runaway.
>
>
> ** The fact that MOVs deteriorate means it is hazardous to have them wired from active to safety ground. Same argument goes for regular metallised film capacitors which also deteriorate when exposed to AC supply voltages - then explode.

In the US the likely maximum surge energy at a MOV in a plug-in
protector is a tiny 35J, and that includes for the largest probable
power line surge (as in my 1st post). The simplest UL listed protector
here will have a joule rating far above that.

The joule rating of a MOV is the single event energy that will put the
MOV at defined end of life (but still functional). Looking at MOV
ratings curves, if the MOV gets single hits that are far below that, the
cumulative rating is far above (like over 10x) the single event rating.
Failure is real unlikely. Coupled with high ratings, that is why some
companies can have protected equipment warranties.

The author of the NIST surge guide has written "in fact, the major
cause of [surge protector] failures is a temporary overvoltage, rather
than an unusually large surge." An example of temporary overvoltage
would be a high voltage distribution wire coming down on the 115/230V
secondary conductors.

You could also say it is hazardous to have leakage and fault currents on
the safety ground.

[Chris Jones]

At least some testers measure the insulation resistance (between
live/neutral and earth) at either 500VDC or 250VDC. The 250V setting is
labelled "MOV". This document explains the testing process:
http://uk.megger.com/getmedia/a5f14a4f-e742-4e85-b7de-db02f5f9a533/PAT-Testing-surge-protected-equipment_AN_en_V01.pdf/

The note from Megger on testing these surge protectors above also seems
to imply that connecting MOVs between live and earth is a common
arrangement, however they show a gas discharge tube between the Earth
wire and the MOVs. It would be interesting to know if this is common and
if so, why and what are its ratings.

Other pages seem to suggest that at least in some cases/countries, MOVs
are connected directly from live to earth.
http://en.wikipedia.org/wiki/Power_strip#Surge_protection_and_filtering
http://www.racktronics.com.au/gallery.php
http://badcaps.net/forum/showthread.php?p=10176

I'm not sure whether this is a good thing, unless you know for sure that
your earth connections are all present and correct, and your RCD/ELCB is
present and working. Whilst I would agree with Phil that a used MOV is
likely to be so leaky as to result in unacceptable current flowing from
live to earth, I'm not sure that many of the appliance standards would
catch this, unless the sequence of tests (during product approval not
PAT) would first damage and later test the leakage of the MOV.

Chris

[Phil Allison]

bud-- wrote:
> On 5/31/2015 1:14 AM, Phil Allison wrote:
> > bud-- wrote:
> > Phil Allison wrote:
> >
> >>> ** Connecting MOVs to ground like that in a *plug-in device* is prohibited on safety grounds under EU and similar regulations as followed in most 230/240 V places - like Australia where I am.
> >>>
> >>> MOVs either have or can develop after some use leakage currents well in excess of the maximum permitted, which is only a milliamp or so for most categories of appliances.
> >>>
> >>> The only components that may be so connected are agency approved " Y caps " with values like 4.7nF - while MOVs and " X caps" always go across the line.
> >>>
> >>
> >>
> >> Standard practice in the US for plug-in protectors is MOVs from H-N,
> >> H-G, N-G.
> >
> >
> > ** I really doubt using three MOVs like that is *normal* practice - certainly one never sees it in entertainment electronics or test gear, whether made in the USA or elsewhere.
>
> Entertainment electronics may have some surge protection but is not
> intended to protect against major surges.

** Nor are an plug-in surge protectors.

You are bullshitting wildly.

> As can be seen from the IEEE surge guide, 3 MOVs is absolutely standard
> practice in the US.

** Really - you must send me a copy.

Yawnnnnn....

> Because of the additional risks added by having only H-N protection in
> plug-in protectors

** There is no risk that derives from the device itself - until you add MOVs to ground. You really need to pay attenion to the context.

(as in my last post) I suspect 3 MOVs is common
> practice elsewhere,

** What you "suspect" is on no value, at all, to anyone.

> H-N only protectors can increase risk, not reduce it.

** Insane crap.

> Gareth does not know what is connected H-G.

** Gareth is an even bigger bullshitter than you.

> All the packaging protectors come in that I have seen indicate what the
> protection is (H-N, H-G, N-G). I suspect it would elsewhere. I am not
> interested in looking.

** ROTFL.

> >>
> >> The normal failure mode for MOVs is after sufficient energy hits they
> >> start to conduct at lower voltages, eventually conduct at 'normal'
> >> voltages, and go into thermal runaway.
> >
> >
> > ** The fact that MOVs deteriorate means it is hazardous to have them wired from active to safety ground. Same argument goes for regular metallised film capacitors which also deteriorate when exposed to AC supply voltages - then explode.
>
>
> In the US the likely maximum surge energy at a MOV in a plug-in
> protector is a tiny 35J, and that includes for the largest probable
> power line surge (as in my 1st post). The simplest UL listed protector
> here will have a joule rating far above that.

** Another one of you wild suspicions ?

> You could also say it is hazardous to have leakage and fault currents on
> the safety ground.

** It is.

You totally fail to see what the safety issue is.

You have no understanding of why no ordinary or class X film caps of any value can be wired from line to safety ground, ONLY special class Y types are permitted in restricted values. True in the USA, the EU and elsewhere.




... Phil

[bud--]

On 5/31/2015 7:53 AM, Chris Jones wrote:
>
> however they show a gas discharge tube between the Earth
> wire and the MOVs. It would be interesting to know if this is common and
> if so, why and what are its ratings.

As a guess, the GDT prevents leakage Phil is worried about, and the MOV
prevents "follow-on" discharge through the GDT right after the surge is
over and normal power is present.

>
> Whilst I would agree with Phil that a used MOV is
> likely to be so leaky as to result in unacceptable current flowing from
> live to earth,

As I responded to Phil, this is actually quite unlikely (at least in the
US).

> I'm not sure that many of the appliance standards would
> catch this, unless the sequence of tests (during product approval not
> PAT) would first damage and later test the leakage of the MOV.

US-UL tests include a series of test surges, after which the device has
to be functional (in particular, it is not 'leaking').

Later tests may cause the device to fail, but it must fail safely.

[Phil Allison]

Chris Jones wrote:

>
>
> At least some testers measure the insulation resistance (between
> live/neutral and earth) at either 500VDC or 250VDC. The 250V setting is
> labelled "MOV".
> This document explains the testing process:
>
> http://uk.megger.com/getmedia/a5f14a4f-e742-4e85-b7de-db02f5f9a533/PAT-Testing-surge-protected-equipment_AN_en_V01.pdf/

** That note is dated *2014* and admits that PAT testers without a 250VDC setting cannot distinguish devices with MOVs to ground from faulty devices.
This is not an acceptable situation.

IIRC, the "Megger 4DV" that I saw had no such setting.

> The note from Megger on testing these surge protectors above also seems
> to imply that connecting MOVs between live and earth is a common
> arrangement,

** So common that they noticed it only last year !!!

Yawnnnnnnnnnnnnn.....

> Other pages seem to suggest that at least in some cases/countries, MOVs
> are connected directly from live to earth.

** Sure - in the USA, but only in some surge protectors.

> Whilst I would agree with Phil that a used MOV is
> likely to be so leaky as to result in unacceptable current flowing from
> live to earth, I'm not sure that many of the appliance standards would
> catch this,

** No need to "catch" it, the fitting of MOVs to ground inside a plug-in appliance is simply prohibited.

The standard 500V DC leakage test would indicate the existence of a MOV wired to ground - if eyeballs were not able to.



... Phil

[bud--]

On 5/31/2015 8:11 AM, Phil Allison wrote:
> bud-- wrote:
>
>> As can be seen from the IEEE surge guide, 3 MOVs is absolutely standard
>> practice in the US.
>
>
> ** Really - you must send me a copy.
>
> Yawnnnnn....

Link to the IEEE surge guide was in my first post. Excellent information
from a completely reliable source. If you read it you might learn something.

>
>> H-N only protectors can increase risk, not reduce it.
>
> ** Insane crap.

The problem I described, with 3 MOV protectors, is well know and in a
published research paper by the author of the NIST surge guide (guide is
also linked in my 1st post). Problems with using only a H-N MOV are
considerably greater. The fix in the paper was to run not just power
wires, but also signal wires through the protector with the voltage
limited from all wires to the ground at the protector (as also described
starting page 30 in the IEEE surge guide, which is linked-to in my 1st
post).

>> In the US the likely maximum surge energy at a MOV in a plug-in
>> protector is a tiny 35J, and that includes for the largest probable
>> power line surge (as in my 1st post). The simplest UL listed protector
>> here will have a joule rating far above that.
>
> ** Another one of you wild suspicions ?

Published research by the author of the NIST surge guide , who was the
US-NIST surge expert.

My information comes from the IEEE, the NIST, and published research.


Sometimes you post really interesting information.

Sometimes not.

This is one of the latter.

[Phil Allison]

bud-- wrote:

> bud-- wrote:
> >
> >> As can be seen from the IEEE surge guide, 3 MOVs is absolutely standard
> >> practice in the US.
> >
> >
> > ** Really - you must send me a copy.
> >
> > Yawnnnnn....
>
> Link to the IEEE surge guide was in my first post. Excellent information
> from a completely reliable source.

** Fraid it is neither.

Nothing more than a simplistic, broad overview with no examples of any commercial products.

It does NOT say what you claim.

> >
> >> H-N only protectors can increase risk, not reduce it.
> >
> > ** Insane crap.
>
> The problem I described,

** Listen you pompous halfwit:

the ** SAFETY HAZARD ** I am referring to is severe electric shock delivered to the user of the device.

Have you no idea how that can happen with MOVs wired to ground in a plug in device? ??

Obviously not - since the IEEE etc docs you linked do not bother to mention it.

Do I really have to rub your stupid nose in it ?

> Sometimes you post really interesting information.

** Not just sometimes.

And you still have NO damn clue about the electric shock hazard inherent in connecting a MOV, cap, resistor or any sort of load from the current carrying conductors to safety ground inside a plug-in device.



... Phil

[whit3rd]

On Sunday, May 31, 2015 at 12:14:55 AM UTC-7, Phil Allison wrote:
> bud-- wrote:
> Phil Allison wrote:
>
> > > ** Connecting MOVs to ground like that in a *plug-in device* is prohibited on safety grounds under EU and similar regulations

> > Standard practice in the US for plug-in protectors is MOVs from H-N,
> > H-G, N-G.

> ** I really doubt using three MOVs like that is *normal* practice - certainly one never sees it in entertainment electronics or test gear, whether made in the USA or elsewhere.

It isn't acceptable for US medical devices, but it isn't unknown, either. It's always
combined with a fuse, where I've seen it.

[Cursitor Doom]

On Sun, 31 May 2015 23:50:30 -0700, Phil Allison wrote:

> Do I really have to rub your stupid nose in it ?

"I'm so sorry; he's from Barcelona."

[bud--]

On 6/1/2015 12:50 AM, Phil Allison wrote:
> bud-- wrote:
>
>> bud-- wrote:
>>>
>>>> As can be seen from the IEEE surge guide, 3 MOVs is absolutely standard
>>>> practice in the US.
>>>
>>>
>>> ** Really - you must send me a copy.
>>>
>>> Yawnnnnn....
>>
>> Link to the IEEE surge guide was in my first post. Excellent information
>> from a completely reliable source.
>
> ** Fraid it is neither.

https://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineers
The IEEE currently has 400,000 members.

The surge guide comes from the Surge Protection Devices Committee. That
is people who actually design surge protectors and protection schemes.
They also write standards for surge protection.

>
> Nothing more than a simplistic, broad overview with no examples of any commercial products.
>
> It does NOT say what you claim.

For anyone with minimal reading skills, it shows how surge protectors
are connected and how they work (at least in the US). Namely MOVs from
H-N, H-G, and N-G.

>>>
>>>> H-N only protectors can increase risk, not reduce it.
>>>
>>> ** Insane crap.
>>
>> The problem I described,
>
>
> ** Listen you pompous halfwit:

So do I trust people who actually design surge protection and have done
basic research, all of whom support what I have written?

Or do I trust Phil, who is currently in troll mode?

...that's a tough one...

[Phil Allison]

bud the dope -- wrote:


( snip piles of irrelevant crap about the IEEE)

** Listen you pompous halfwit:

the ** SAFETY HAZARD ** I am referring to is severe electric shock delivered to the user of the device.

Have you no idea how that can happen with MOVs wired to ground in a plug in device? ??

Obviously not - since the IEEE etc docs you linked do not bother to mention it.

Do I really have to rub your stupid nose in it ?

And you still have NO damn clue about the electric shock hazard inherent in connecting a MOV, cap, resistor or any sort of load from the current carrying conductors to safety ground inside a plug-in device.

Obviously, you cannot answer these important points.

FYI:

The executive director of the IEEE is a guy I went to high school and university with - Jim Prendergast.

https://www.ieee.org/about/management_council.html?WT.mc_id=lp_ab_imc

Totally irrelevant, of course.


... Phil

[Cydrome Leader]

I have to agree with Phil here. The key here is plug-in device. This is
why "surge strips" or any sort of power strip with surge supression are
just pure trash.

when these devices are not on fire, and are able to shunt some sort of
surge, real or imagined into ground, you elevate the voltage on that
segment of the ground circuit. That destroys or interferes with all the
other equiment connected to that that ground.

Keep in mind lots of grounds aren't even really grounded, or grounded
properly, especially in homes, old homes or places with poorly done
electrical work. The end of the line is the worst place to try to stop a
surge.

I had to remove some walls in a new space office space and wiring we found
was appalling. Had to have the building engineer drop by to take a look
for himself. He was baffled as well. Disconneting the weird wiring even
resulted in one light switch causing the lights to just flicker instead
off turn off in the off position. It wasn't even a two way switch.

[bud--]

On 6/3/2015 9:40 AM, Cydrome Leader wrote:
>
> I have to agree with Phil here. The key here is plug-in device. This is
> why "surge strips" or any sort of power strip with surge supression are
> just pure trash.

Experts at the IEEE and NIST say say they are effective. That is based
on research and experience.

Where is a source that agrees with you?

>
> when these devices are not on fire, and are able to shunt some sort of
> surge, real or imagined into ground, you elevate the voltage on that
> segment of the ground circuit. That destroys or interferes with all the
> other equiment connected to that that ground.

The IEEE surge guide clearly explains how plug-in protectors work. It is
not primarily by earthing the surge.

And as any competent manufacturer, along with the IEEE and NIST make
clear, and as I wrote in my 1st post, "if using a plug-in protector all

interconnected equipment needs to be connected to the same protector.

External connections, like coax also must go through the protector. As

explained in the IEEE surge guide (starting page 30) plug-in protectors

work primarily by limiting the voltage from each wire to the ground at
the protector. To do that all wires must go through the protector."

As I also pointed out, the amount of energy that has any reasonable
probability of being absorbed in a MOV at a plug-in protector is
asurprisingly small 35 joules, and in 13 of 15 test cases it was 1 joule
or less (US). That is based on research. The largest energy is actually
not for the largest surges. One reason the energy is so small is there
is arc-over at about 6kV from panel busbars to the enclosure - and the
established arc is hundreds of volts. That dumps most of the energy of a
large surge to earth, and limits the exposure in a house. The second
reason is a surge is a very short event. That means the current
components are relatively high frequency. That means the impedance of
the branch circuit is more important than the resistance. The result is
the amount of surge current is quite limited which means that the energy
is limited.

What I have written is based on surge guides from reliable sources which
I have linked to, and on published research.

On the other side are opinions by you and Phil.

Maybe if you figured out how they worked....

[Ralph Mowery]

"bud--" <nu...@void.com> wrote in message
news:556f987f$0$29478$c3e8da3$e074...@news.astraweb.com...

> On 6/3/2015 9:40 AM, Cydrome Leader wrote:
>>
>> I have to agree with Phil here. The key here is plug-in device. This is
>> why "surge strips" or any sort of power strip with surge supression are
>> just pure trash.
>
> Experts at the IEEE and NIST say say they are effective. That is based on
> research and experience.
>
>

Personal experiance tells me they work. During a thunderstorm a
transformer let go that feed my house and three others. I had surge strips
on all the electronics that plug in the wall. Two of the strips and a MOV
on the stove were taken out. No other damage. Two of the other houses lost
their TV sets and some other things. Did not talk to the third house to see
if he lost anything or not.

[Phil Allison]

Ralph Mowery wrote:

Cydrome Leader wrote:
>
>>
> >> I have to agree with Phil here. The key here is plug-in device. This is
> >> why "surge strips" or any sort of power strip with surge supression are
> >> just pure trash.
> >
> > Experts at the IEEE and NIST say say they are effective. That is based on
> > research and experience.
> >
> >
> Personal experiance tells me they work.

** Simply because MOVs work - ie they conduct hard with large voltages applied.

Under lab test conditions, they work as advertised.


However, a NASTY electric shock hazard arises when they become damaged, go leaky and for whatever reason the safety earth at the power outlet is high resistance ( corroded for example ) or has become non existent.

Then, the MOV used on the hot or active line will conduct AC current to all the exposed metal of all the items plugged into the surge protector's outlets - plus all interconnected items in a home computer, audio or video system.




.... Phil

[bud--]

On 6/4/2015 2:09 AM, Phil Allison wrote:
> Ralph Mowery wrote:
>
> Cydrome Leader wrote:
>>
> >>
>>>> I have to agree with Phil here. The key here is plug-in device. This is
>>>> why "surge strips" or any sort of power strip with surge supression are
>>>> just pure trash.
>>>
>>> Experts at the IEEE and NIST say say they are effective. That is based on
>>> research and experience.
>>>
>>>
>> Personal experiance tells me they work.

I have seen a number of people say they are effective in high lightning
- high surge environment Florida.

>
>
> ** Simply because MOVs work - ie they conduct hard with large voltages applied.
>
> Under lab test conditions, they work as advertised.
>
>
> However, a NASTY electric shock hazard arises when they become damaged, go leaky

A strawman, since as I have written that is very unlikely. The surge
energy they experience (at least in the US) is tiny even for near worst
case surges.

> and for whatever reason the safety earth at the power outlet is high resistance ( corroded for example ) or has become non existent.

Of course that is a problem with, for instance, a refrigerator that
develops 'leakage'. I have seen several reports of refrigerators that
will trip a GFCI (trips on about 5mA ground fault) but will run on a
circuit without a GFCI.

And then there is a H-G fault on 'grounded' metal cased equipment.

Another strawman - where are all the dead bodies from surge protectors?

The IEEE says they are effective.

So does the US-NIST.

Reliable sites that agree with you - zero.

[Cydrome Leader]

bud-- <nu...@void.com> wrote:
> On 6/3/2015 9:40 AM, Cydrome Leader wrote:
>>
>> I have to agree with Phil here. The key here is plug-in device. This is
>> why "surge strips" or any sort of power strip with surge supression are
>> just pure trash.
>
> Experts at the IEEE and NIST say say they are effective. That is based
> on research and experience.
>
> Where is a source that agrees with you?

I don't know, every business that has surge sensitive equipment that
installs proper service entrance surge surpression devices instead of
using "power strips" and other nonsense.

You can read white papers from a committee all day and take that as how
things work. It's not necessarily what happens back in the real world.

>> when these devices are not on fire, and are able to shunt some sort of
>> surge, real or imagined into ground, you elevate the voltage on that
>> segment of the ground circuit. That destroys or interferes with all the
>> other equiment connected to that that ground.
>
> The IEEE surge guide clearly explains how plug-in protectors work. It is
> not primarily by earthing the surge.

That's the problem. What happens when I send 1500 volt surge down the hot
side of 120 volt circuit? A mov shunts that do neutral and all is good?
It's real good to have voltages on your neutral circuit.

Plug in protectors are garbage unless your source of surges is small and
on the same ciruit you're protecting. So yeah, plug your old, broken, arcy
electric drill into a $2 power strip.

> And as any competent manufacturer, along with the IEEE and NIST make
> clear, and as I wrote in my 1st post, "if using a plug-in protector all
> interconnected equipment needs to be connected to the same protector.
> External connections, like coax also must go through the protector. As
> explained in the IEEE surge guide (starting page 30) plug-in protectors
> work primarily by limiting the voltage from each wire to the ground at
> the protector. To do that all wires must go through the protector."

This is an unrealistic scenario in real life. Back to what I said earier,
any business that has critical load, even down to POS systems will install
a service entrance surge surpressor, sometimes with ground/neutral
rebonding isolation transformers, usually for a cash register and printer.
No consumer in history has ever given a hoot about the perfect star
topolgy for their power strip. Those devices are jokes.

> As I also pointed out, the amount of energy that has any reasonable
> probability of being absorbed in a MOV at a plug-in protector is
> asurprisingly small 35 joules, and in 13 of 15 test cases it was 1 joule
> or less (US). That is based on research. The largest energy is actually
> not for the largest surges. One reason the energy is so small is there
> is arc-over at about 6kV from panel busbars to the enclosure - and the
> established arc is hundreds of volts. That dumps most of the energy of a
> large surge to earth, and limits the exposure in a house. The second
> reason is a surge is a very short event. That means the current
> components are relatively high frequency. That means the impedance of
> the branch circuit is more important than the resistance. The result is
> the amount of surge current is quite limited which means that the energy
> is limited.
>
> What I have written is based on surge guides from reliable sources which
> I have linked to, and on published research.
>
> On the other side are opinions by you and Phil.
>
> Maybe if you figured out how they worked....

That's right.

[Michael A. Terrell]

Mark Justice wrote:
>
> On Thu, 28 May 2015 15:22:28 +1000, Trevor Wilson wrote:
>
> > On 28/05/2015 12:21 PM, Ron D. wrote:
> >> On Wednesday, May 27, 2015 at 5:16:28 PM UTC-4, Ron D. wrote:
> >>> I'll point you here: http://www.gryphon-inc.com/White_Papers.html
> >>>
> >>> I've had extreme success with Powervar/ONEAC products. Like 25 years
> >>> on a very critical computer system. The only failures were mechanical
> >>> like fans and floppy drives. The hard drive was on 15 years before
> >>> the system was upgraded. It did cost about $1K USD in the 80's for
> >>> about 1000 W. Later, two other systems got the same technology.
> >>>
> >>> Usually, the warranty and the sales receipt helps a lot. Less
> >>> critical systems got the tripp-lite isobar which oneac doesn;t like
> >>> either. I did see an ISOBAR fry and Trip-lite replaced the connected
> >>> equipment.
> >>>
> >>> I had an APC surge suppressor (given to me) and it's is supposed to be
> >>> replaced because it causes fires. I think it's been close to 3 months
> >>> now and no replacement APC. Furthermore, that APC did not protect
> >>> itself. Oh maybe it did? It prevent itself from frying by blowing a
> >>> thermal fuse and passing the surge to the equipment and lighting a
> >>> LED.
> >>
> >> A whole house suppressor would not be a bad idea either.
> >>
> >>
> > **For what purpose? An event that is so incredibly rare that the average
> > person won't see one in several life-times.
> >
> > The whole 'surge suppressor' industry is a con. It is the only
> > significant profit area left for retailers of domestic electronic
> > equipment. Profit margins run to several hundred percent. That said: A
> > whole house suppressor is a reasonably economical solution to an almost
> > non-existent problem. It must be fitted by a qualified electrical
> > contractor.
> >
> > FWIW: The only time I have ever heard of a significant surge on a power
> > line, was at my previous home, before I moved in. A 5kV railway bearer
> > fell across the 240VAC mains supply. This was in the early 1970s. It
> > wiped out the electronic and electrical equipment for several blocks. I
> > doubt that anything that can be purchased retail can protect against
> > such a rare event.
>
> Not in Florida.
> I was checking a Sunbeam frying pan to see if it worked plugging it in in
> the garage when kbang.
> Tossed across the garage I went to see what was damaged, besides me.
>
> Several outlets in the house had carbon scarring around them, the
> splitter to the color T.V. was mostly vaporized with just a small piece
> of circuit board with the ghostly outlines of parts no longer of the
> Earth.
>
> The color T.V. worked only as black and white for some weeks when the
> color decided to return.
> Outside a bruise or three and a short case of the stunned shakes I was
> unhurt.
>
> Not unusual around these parts to lose equipment due to surges coming in
> through the line, YMMV.


I've seen outlets blown out of walls by nearby lightning strikes. One TV
station I worked at for a year was hit by lightning in two different
cities. One strike took out all the computer terminals, the computer,
the phone system, the 11 GHZ STL, and some wiring in the concrete
building. The other struck a large tent at a live remote, and knocked
out everything in the remote production unit. Both of these were in
Florida, where I've seen reports of over 1100 lightning strikes in 30
minutes.

[Phil Allison]

bud the troll-- wrote:


> >
> >
> > However, a NASTY electric shock hazard arises when they become damaged, go leaky
>

> A strawman ..

** A fake made out of worthless stuff describes you very eloquently.

> The IEEE says they are effective.

** But fail to address the real issues.

.... Phil

[jurb...@gmail.com]

>"Both of these were in
>Florida, where I've seen reports of over 1100 lightning strikes in 30
>minutes. "

Friend of mine used to live in FLorida and said it is the lightmning capital of the world. Can't be sure it is true but he told me he lost so many answering machines he decided to just get voicemail from the phone company.

Back then things were a bit different. Answering machines were more popular and voicemail wasn't. Bottom line though, you can't do call screening on voicemail.

[Michael A. Terrell]

One strike where I lived vaporized the line from the house to the
pedestal, a mile away. There, it blew up the SLIC, then continued the
rest of the way into town, to the C.O. The pair was bad all the way from
our NIC, to the C.O. It destroyed the C-band sat system, a stereo, a TV
and a computer monitor that wasn't connected to the PC at the time. The
video cable was wrapped around the base on the monitor. The only thing
that wasn't damaged was the microwave oven, which was plugged into a
surge suppresser.

[Ralph Mowery]

<jurb...@gmail.com> wrote in message
news:ba7dac3a-ab06-4c54...@googlegroups.com...

Most likely his problem was the surges comming in on the phone lines and not
the power lines. I keep up a repeater station on the top of a small hill
around here. In over 35 years only one diode in a power supply and a
transistor in an antenna preamp went bad. However the telephone interface
would burn out some protection resistors or blow some fuses in the phone
line about once a year if not more. Over the years I learned how to keep
adding protection to the phone lines external to the equipment and slowed
down the problems.

Finally did away with the phone interface and have not had any problems in
years.

[bud--]

On 6/4/2015 1:45 PM, Cydrome Leader wrote:
> bud-- <nu...@void.com> wrote:
>> On 6/3/2015 9:40 AM, Cydrome Leader wrote:
>>>
>>> I have to agree with Phil here. The key here is plug-in device. This is
>>> why "surge strips" or any sort of power strip with surge supression are
>>> just pure trash.
>>
>> Experts at the IEEE and NIST say say they are effective. That is based
>> on research and experience.
>>
>> Where is a source that agrees with you?
>
> I don't know, every business that has surge sensitive equipment that
> installs proper service entrance surge surpression devices instead of
> using "power strips" and other nonsense.

The discussion has been about home protection - you are changing the
subject.

And the discussion has mostly been about plug-in protectors because that
is what the original question was about.

As I wrote "a service panel protector is likely to protect anything
connected only to power wiring."
Service panel protectors do not, by themselves, prevent high voltages
from developing between power and signal wires. Proper protection
requires a short ground wire from the building phone, cable, ... entry
protector to the power earthing system. Commercial buildings are likely
to have that, homes less likely. And homes are likely have more exposure
to external signal wires (phone, cable, dish,...)

You can also have pickup from a near lightning strike, with power and
signal wiring acting as antennas. Interior commercial network data
communication hardware has, if I remember right, several thousand volts
of immunity, which is likely to protect from near strikes. Commercial
systems are also likely to have been designed by a competent person.

>
> You can read white papers from a committee all day and take that as how
> things work. It's not necessarily what happens back in the real world.

The IEEE authors work in the real world, including commercial protection.

>
>>> when these devices are not on fire, and are able to shunt some sort of
>>> surge, real or imagined into ground, you elevate the voltage on that
>>> segment of the ground circuit. That destroys or interferes with all the
>>> other equiment connected to that that ground.
>>
>> The IEEE surge guide clearly explains how plug-in protectors work. It is
>> not primarily by earthing the surge.
>
> That's the problem. What happens when I send 1500 volt surge down the hot
> side of 120 volt circuit? A mov shunts that do neutral and all is good?
> It's real good to have voltages on your neutral circuit.

With a plug-in protector, 1500V on the hot wire at the panel would
result in maybe 500V between the 'ground' at the protector and the
'ground' at the service. The voltages on power and signal wires are
clamped to the protector ground. Voltages between wires going to the
protected equipment is safe for the protected equipment.

Much better than leaving 1500V on the hot wire.

Protection can be provided in multiple ways. Which is appropriate
depends on the situation.

>
> Plug in protectors are garbage unless your source of surges is small and
> on the same ciruit you're protecting. So yeah, plug your old, broken, arcy
> electric drill into a $2 power strip.

Small surges are not likely any risk.

Repeating, since you ignored it (twice):
"The author of the NIST surge guide also investigated how much energy
might be absorbed in a MOV in a plug-in protector. Branch circuits were
10m and longer, and the surge on incoming power wires was up to 10,000A
(worst case, as above). The maximum energy at the MOV was a surprisingly
small 35 joules. In 13 of 15 cases it was 1 joule or less. There are a
couple simple reasons the energy is so low... Any UL listed protector in
the US will have ratings higher than that, and much higher ratings are
readily available."

Plug-in protectors are likely to handle the worst surges (lightning caused).

>
>> And as any competent manufacturer, along with the IEEE and NIST make
>> clear, and as I wrote in my 1st post, "if using a plug-in protector all
>> interconnected equipment needs to be connected to the same protector.
>> External connections, like coax also must go through the protector. As
>> explained in the IEEE surge guide (starting page 30) plug-in protectors
>> work primarily by limiting the voltage from each wire to the ground at
>> the protector. To do that all wires must go through the protector."
>
> This is an unrealistic scenario in real life. Back to what I said earier,
> any business that has critical load, even down to POS systems will install
> a service entrance surge surpressor, sometimes with ground/neutral
> rebonding isolation transformers, usually for a cash register and printer.

The conversation has been about home protection, where properly
connected plug-in protectors can be very effective. What is appropriate
depends on the situation. In commercial they may or may not be an
appropriate way to protect in a particular instance, and there are
protection schemes that are useful in commercial/industrial that would
not be used in homes.

> No consumer in history has ever given a hoot about the perfect star
> topolgy for their power strip.

Only the ones who understand protection (or who can RTFM).
If you do not run all external wires through a plug-in protector you
likely should not be using one.

> Those devices are jokes.

Properly connected plug-in protectors are effective. Both surge guides
agree. They are also recognized as one of the effective protection
methods in the IEEE "Emerald" book, which is about protecting "sensitive
electronic equipment" (commercial environments).

Still missing, competent sources that agree with you that they are "jokes"