harry wrote:
On Jun 4, 3:43 pm, "Ed Pawlowski" wrote:
We had a near lightening strike that sent a surge though the power lines.
Not sure where the hit was, but I did have some damage.

My wife called me at work after a thunderstorm and said she saw a big red
ball in the driveway and then some of the lights went out. The doorbell
rang and would not stop ringing. I told her to take a wire off the chimes
and they stopped, but a breaker was tripped and would not reset. The bell
button has a diode in it and that may have taken the hit.

When I got home, I took the two wires off of the breaker and it still did
not reset so I replaced the breaker. One of the circuits was OK, the other
had a short and tripped the breaker. Since it was not getting dark and it
was still raining, the hunt would wait a day. Next day, I went out to the
(detached) garage and found an X-10 module I use to control an outdoor light
was blown apart and burnt. The plastic cover was gone, the insides were
soot covered. I'm wondering if the jolt came in that way or out, it was
the furthest away from the electric panel.

I'm going to replace the receptacle it was plugged into also. I've not
pulled that out yet, but I'm not taking any chances. Once replaced. I'll
hook the wire back to the breaker.

Losses we HD TV, Surround sound receiver, X-10 module, computer router,
doorbell.

The good news is: I now have a 47" TV with far better picture than my 5
year old 32" and a better sound system.
More stuff is on surge protectors too.

It's quite likely your actual house was struck, especially if it is
isolated and has any high points. You're wife could have been killed
so count yourselves lucky.
You need to get external lighning protection rods if you house IS high
and is away from other high points. These are quite expensive and
need regular checks. You could do these yourself if your technical.

The "spike" or transient protection device that will protect agains
the strike you experienced has not been made and never will be. You
can get deviced that will protect against strikes on the electric
distribution system that are miles awy but that's all.

Nonsense.

The best easily available info on surge protection I have seen is in a
guide form the IEEE - the major association of electrical and electronic
engineers:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
and in a much simpler guide from the US-NIST
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

The author of the NIST guide was the NIST guru on surges and has many
published technical papers. One of them looks at a 100,000 A lightning
strike to the primary wire on a utility pole behind a house with typical
urban overhead distribution. Only 5% of lightning strikes are stronger,
and with the nearness this is a near worst case (excluding a direct
strike to the house that requires lightning rods). There are multiple
paths to ground; the current going to the house on the service neutral
is about 30,000A. The current on the neutral is directly earthed by the
neutral-ground-earthing electrode bond in US services. About 10,000A
transfers to the hot wires. This is the maximum that has any reasonable
expectation of occurring, at least for a house. Service panel
suppressors with far higher than 10,000A current capacity per wire are
readily available.

Another paper looked at the energy dissipated in a plug-in suppressor
with 10,000A coming in on a service wire and no service panel
suppressor. With branch circuits 30 ft and longer the energy was
surprisingly small - 35 joules max. One reason is that at about 6,000V
there is arc-over from the panel busbars to the enclosure. After the arc
stabilizes the voltage is hundreds of volts. The enclosure is connected
to the earthing system, so this dissipates most of the surge energy. The
other reason is that a surge is a short event, thus a relatively high
frequency event. The impedance of the branch circuit greatly limits the
current, and thus the energy that can reach the plug-in suppressor. A
plug-in suppressor is likely to protect against even a very near
lightning strike. And there is better protection if there is also a
service panel suppressor.

All these
devices do is store the enegy of the transient in a capacitor or coil
& then discharge it to ground. So they will cope with switching
transients and similar but that's all.

From the IEEE guide: "the vast majority (90%) of both hard-wired and
plug-in protectors use MOVs to perform the voltage-limiting function. In
most AC protectors, they are the only significant voltage limiters."

Next time there's a big storm, the only protection for your electrical
appliances is to turn the electricity isolator off where it enters
the house.

That won't necessarily work (arc-over at the meter may keep the voltage
low enough). Because of arc-over in the panel (and receptacles) at about
6,000V, open switches have a good chance of not arcing across.

===========
I assume the $150 and $6 per month is for a suppressor installed at the
meter by the utility. I would install (or an electrician could install)
a suppressor at the service panel as in Pete's post. The IEEE guide has
recommendations on surge current ratings. Any surge suppressor
(including UPSs with surge protection added) should be listed under UL1449.

Phone wires have long had an entrance protector. The ground wire from
the protector to the earthing at the service panel has to be short. With
a strong surge, the building "ground" can rise thousands of volts above
"absolute" earth potential. Much of the protection is to have power and
phone and cable wires rise together. Cable companies can be derelict in
properly connecting entrance ground blocks to the earthing system. Dish
companies are even worse. For cable, in particular, the connection also
needs to be short. Coax ground blocks do not limit the voltage from the
center conductor to the shield - could rise to 4,000V.

--
bud--

On Jun 5, 1:45*am, bud-- wrote:
harry wrote:
On Jun 4, 3:43 pm, "Ed Pawlowski" wrote:
We had a near lightening strike that sent a surge though the power lines.
Not sure where the hit was, but I did have some damage.

My wife called me at work after a thunderstorm and said she saw a big red
ball in the driveway and then some of the lights went out. *The doorbell
rang and would not stop ringing. *I told her to take a wire off the chimes
and they stopped, but a breaker was tripped and would not reset. *The bell
button has a diode in it and that may have taken the hit.

When I got home, I took the two wires off of the breaker and it still did
not reset so I replaced the breaker. *One of the circuits was OK, the other
had a short and tripped the breaker. *Since it was not getting dark and it
was still raining, the hunt would wait a day. *Next day, I went out to the
(detached) garage and found an X-10 module I use to control an outdoor light
was blown apart and burnt. *The plastic cover was gone, the insides were
soot covered. * I'm wondering if the jolt came in that way or out, it was
the furthest away from the electric panel.

I'm going to replace the receptacle it was plugged into also. *I've not
pulled that out yet, but I'm not taking any chances. *Once replaced. I'll
hook the wire back to the breaker.

Losses we *HD TV, Surround sound receiver, X-10 module, computer router,
doorbell.

The good news is: *I now have a 47" TV with far better picture than my 5
year old 32" and a better sound system.
More stuff is on surge protectors too.

It's quite likely your actual house was struck, especially if it is
isolated and has any high points. * You're wife could have been killed
so count yourselves lucky.
You need to get external lighning protection rods if you house IS high
and is away from other high points. *These are quite expensive and
need regular checks. You could do these yourself if your technical.

The "spike" or transient protection device that will protect agains
the strike you experienced has not been made and never will be. * You
can get deviced that will protect against strikes on the electric
distribution system that are miles awy but that's all.

Nonsense.

The best easily available info on surge protection I have seen is in a
guide form the IEEE - the major association of electrical and electronic
engineers:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversio...
and in a much simpler guide from the US-NIST
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

The author of the NIST guide was the NIST guru on surges and has many
published technical papers. One of them looks at a 100,000 A lightning
strike to the primary wire on a utility pole behind a house with typical
urban overhead distribution. Only 5% of lightning strikes are stronger,
and with the nearness this is a near worst case (excluding a direct
strike to the house that requires lightning rods). There are multiple
paths to ground; the current going to the house on the service neutral
is about 30,000A. The current on the neutral is directly earthed by the
neutral-ground-earthing electrode bond in US services. About 10,000A
transfers to the hot wires. This is the maximum that has any reasonable
expectation of occurring, at least for a house. Service panel
suppressors with far higher than 10,000A current capacity per wire are
readily available.

Another paper looked at the energy dissipated in a plug-in suppressor
with 10,000A coming in on a service wire and no service panel
suppressor. With branch circuits 30 ft and longer the energy was
surprisingly small - 35 joules max. One reason is that at about 6,000V
there is arc-over from the panel busbars to the enclosure. After the arc
stabilizes the voltage is hundreds of volts. The enclosure is connected
to the earthing system, so this dissipates most of the surge energy. The
other reason is that a surge is a short event, thus a relatively high
frequency event. The impedance of the branch circuit greatly limits the
current, and thus the energy that can reach the plug-in suppressor. A
plug-in suppressor is likely to protect against even a very near
lightning strike. And there is better protection if there is also a
service panel suppressor.

All these
devices do is store the enegy of the transient in a capacitor or coil
& then discharge it to ground. *So they will cope with switching
transients and similar but that's all.

*From the IEEE guide: "the vast majority (90%) of both hard-wired and
plug-in protectors use MOVs to perform the voltage-limiting function. In
most AC protectors, they are the only significant voltage limiters."

Next time there's a big storm, the only protection for your electrical
appliances is to turn the electricity isolator off *where it enters
the house.

That won't necessarily work (arc-over at the meter may keep the voltage
low enough). Because of arc-over in the panel (and receptacles) at about
6,000V, open switches have a good chance of not arcing across.

===========
I assume the $150 and $6 per month is for a suppressor installed at the
meter by the utility. *I would install (or an electrician could install)
a suppressor at the service panel as in Pete's post. The IEEE guide has
recommendations on surge current ratings. Any surge suppressor
(including UPSs with surge protection added) should be listed under UL1449.

Phone wires have long had an entrance protector. The ground wire from
the protector to the earthing at the service panel has to be short. With
a strong surge, the building "ground" can rise thousands of volts above
"absolute" earth potential. Much of the protection is to have power and
phone and cable wires rise together. *Cable companies can be derelict in
properly connecting entrance ground blocks to the earthing system. Dish
companies are even worse. For cable, in particular, the connection also
needs to be short. Coax ground blocks do not limit the voltage from the
center conductor to the shield - could rise to 4,000V.

--
bud--- Hide quoted text -

- Show quoted text -

When I had a strike costing about 20000 the only things not affected
were those on Tripp Lite surge protectors, Trip Lite has a lifetime
warranty covering lightning damage. Even cheap little things help