AC Power Surge Protection?

[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-- <null@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.

 

[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

 

[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.

 

"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]

jurb6006@gmail.com wrote:

"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.

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]

<jurb6006@gmail.com> wrote in message
news:ba7dac3a-ab06-4c54-a33c-21d9d6163598@googlegroups.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.

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-- <null@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"

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.