House got hit by lightning

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Old 07-16-12, 02:23 PM
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House got hit by lightning

Last week ... during the day ... while both my wife and I were at work ... a huge hailstorm passed over our neighborhood.

Came home to find a unresponsive garage door opener. Got out of the car and entered the house. Alarm system did not kick in. Instead, I smelled smoke. Walked over to the wall where the breakers were ... most all the breakers were tripped. Even then, almost every single electronic component that was attached to an outlet ... got fried. Including the TVs, PCs, Routers, PS3, Alarm system etc. etc..

Luckily, the big gadgets like washing machines and mw ovens and cooking range survived. The only large-appliance victim was one of the A/C fan handlers. I had to pay the A/C guy $220 to replace the circuit board. Getting the A/C fixed fast was the highest priority.

A few questions ...

1. What baffled me the most was this cable TV outlet (see below). Nothing was attached to this outlet. Moreover, the other end of that cable was not even connected to the splitter device located outside the house (Comcast box). It was simply hanging loose since the splitter did not have enough room. How that did that spark happen



2. What is the most prudent next step?

My first inclination was to install lightning rods. But I have read conflicting opinions regarding the use of lightning rods (we don't have one). Moreover, installing lightning rods on the roof runs around $6000 in our part of the country. What about whole house surge suppressor (we don't have one). Amazon sells a Leviton (51120-1) for around $200. Is that what I need to start with. Any other suggestions.
 
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Old 07-16-12, 02:28 PM
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Your next step is to call your insurance company, right?
 
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Old 07-16-12, 02:33 PM
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My deductible is $1000. Most of my gadgets are less than a year old ... so its still under factory warranty. Both my TVs are from Vizio and they are sending techs to fix them. My router is leased from Comcast. They replaced it the very next day. I had to fix the A/C fan handler ($220). The garage door opener needs a replacement circuit board ($75). Overall, the estimated out of pocket expense is about $1200. I may be wrong ... but, considering the $1000 deductible .. I decided to not call the insurance company ... worried that they might increase my premium.
 
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Old 07-16-12, 03:12 PM
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I think a lot of policies have limits on electronic devices as well. Just off the top of my head, I know there is a limit on tv replacement on my policy. I may be able to pay extra for more coverage though. I also carry full replacement value insurance.
 
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Old 07-16-12, 03:34 PM
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That spark looks to have shot from the TV coax feed into a steel box.
WAs that unconnected coax near a rain gutter or other metal, like a copper water pipe? Anyway, your home suffered a direct or near direct hit, and it would take a lot of design work to keep damage down in that case. Not impossible, but not trivial either.
 
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Old 07-16-12, 04:21 PM
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Nothing will stop a direct lightning hit. Lightning travels wherever it wants, through whatever it wants. Consider yourself lucky it didn't decide to hit something flammable in the house.
 
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Old 07-16-12, 05:10 PM
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You're very lucky,all you can do is try to reduce damage from lightning strikes.Like Rick said,nothing known to science can stop a direct lightning hit.I seen big steel 24x12" I beams on bridges get twisted and turned into pretzels like they were nothing from lightning strikes.A good surge protector and lightning rods can help prevent some damage.
 
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Old 07-16-12, 05:34 PM
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Happened locally last Friday. Man was thrown across his living room and his house caught fire. At least $100,000 damage and may be a total loss of the house.

Lightning strike's impact blows man across Renton living room | | Renton News

Renton home burns after lightning strike | www.kirotv.com
 
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Old 07-16-12, 05:51 PM
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My deductible is $1000. Most of my gadgets are less than a year old ... so its still under factory warranty
Warranty protection is good, but I doubt you'll get warranty repairs if lightning damage is evident. I would suggest being sure your electric service is properly grounded to a ground rod with resistance to ground 25 ohms or less and adding whole house surge protection on the main service panel and also on your Comcast cable.

What about whole house surge suppressor (we don't have one). Amazon sells a Leviton (51120-1) for around $200. Is that what I need to start with. Any other suggestions
Leviton suppressors are probably fine, but I prefer those from Eaton like this one.

Type-2 Complete Surge Protective Device for Home Electrical Power
 
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Old 07-17-12, 06:28 AM
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Looks like a spark jump from the coax cable jack to a drywall nail (why lightning would want to jump to an isolated piece of metal like a drywall nail baffles me, or does your house have metal studs?)

Or is this one of the mysteries of EMP (electromagnetic pulse) that can induce large voltage differences between isolated metal objects and wires?
 
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Old 07-17-12, 08:17 AM
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> 2. What is the most prudent next step?

Learn why lightning was hunting for earth destructively via appliances. A direct lightning strike far down the street is also a direct strike to every household appliance. Once that energy is inside, then nothing will stop a destructive hunt for earth. Nothing inside can do useful protection.

For over 100 years, facilities that can never have damage earth that surge before it enters. Energy not inside need not hunt destructively. Had a surge been earthed at the service entrance, then protection already inside every appliance would not have been overwhelmed.

Informed consumers earth only one 'whole house' protector. These are sold by responsible companies such as Siemens, Intermatic, General Electric, ABB, Ditek, Polyphaser, ABB, Square D, and Leviton. A Cutler-Hammer solution sells in Lowes and Home Depot for less than $50. Then lightniing need not find earth via your appliances.

Effective solutions have the one and critically important requirement. A wire that must be connected low impedance (ie 'less than 10 feet') to earth ground rods. Only then is lightning not inside the house. How effective is one 'whole house' protector? As effective as the single point earth ground that only you are responsible for providing, upgrading, and maintaining. That ground is required by code. Better protection means you meet and exceed code requirements.

Every wire in every incoming cable must connect low impedance to that earth ground. Your telephone will already have a 'whole house' protector installed for free by the telco. Because superior protection from direct lightning costs so little money and is so effective. But again, it too is only as effective as the earth ground that you are required to provide.

Cable needs no protector. Cable connects to earth by something even better than a protector. A wire. But if that wire to earth is missing, then all protection for the house is compromised.

That picture may show a surge arcing out of an AC wire in the wall. Obtaining earth via the cable. Maybe. But this you do know. You all but inviting lightning to go hunting destructively for earth via your appliances. You do not yet have properly earthed 'whole house' protection. If you had, then all appliances would have been protected.
 
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Old 07-17-12, 10:23 AM
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Westom,

Thank you ! and thanks to every one.

Here is how my home phone lines are wired. I have disconnected the BellSouth phone lines coming to the house. Instead, I have a phone cable going from my Cable Modem to the outside box. This, like before, feeds all phone jacks in the house.

Also, a question. There are two ways to provide whole house protection. Either outside at the electrical ingress or inside the house at the breaker box. Which one would you suggest? Do I need to do both?

I have an electrician coming over this afternoon to check the ground resistance etc. etc.

Will keep you all posted. Thanks !!!!!!
 

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Old 07-17-12, 01:12 PM
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The first thing I would be looking for is where your grounding plates/rods. They may not be installed correctly or need some addressing.
Next thing is to look where the lightening came in. Where you able to figure that out? You might need to look into a lightening rod or something as it appears you can be a potential target.
One you have those two items looked at... it might be worth looking at other measures.

Lightening does weird things. I had one of my batch plants (concrete batch plant) get hit. Blow the phone of the wall and killed all the computers. It also randomly took out computers in the next building. Burnt out the female RJ-45 connector on the cable modem, but the coax end still worked and the ISP could connect to it. Killed the rounter and two of the further computers, but not the closest one.
 
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Old 07-17-12, 02:19 PM
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> There are two ways to provide whole house protection. Either outside
> at the electrical ingress or inside the house at the breaker box. Which
> one would you suggest? Do I need to do both?

You still do not understand the concept. No protector does protection. Where does energy dissipate? If you did not ask yourself that question when posting, then you have still missed the entire point.

That cable box should have a wire that connects to earth ground (that Northern Mike also discusses). What does the protection? The earth ground. What does the wire do? Same that a protector does. And that wire (just like the connection via a protector) must be low impedance (ie 'less than 10 feet'). That number answers your question.

For example, let's assume a 'whole house' protector is in the breaker box. Therefore is earthed by a bare, quarter inch, copper wire from the breaker box to a dedicated earthling electrode. Stop. Go inspect your box. Then read the next paragraph.

How does that bare copper wire route? If up over the foundation and down to an earthing electrode, then protection has been compromised. That low resistance wire also has excessive impedance. It has sharp bends going over the foundation. Must be shorter. Must be routed separate from other wires leaving the breaker box. Must not be inside any metallic conduit.

Best routing is through the foundation and down to an earthing system that exceeds code requirements.

Lightning is not capricious. But so many make assumptions rather than first learn about a science understood even 100 years ago. A direct lightning strike to one building is a direct strike to all interconnected electronics in another building. If well proven solutions are not implemented.

Most will only consider what they see - the protector. And completely ignore what is buried - the protection. Electrodes for each building buried in earth and invisible. What does protection is completely ignored by anyone using observation as a replacement for knowledge.

Does not matter if the Bell South lines are not used. Does that cable still touch the house? Then the Bell South 'installed for free' protector must still be earthed.

How many feet is that maybe 12 AWG wire from cable to earth? Its many purposes include earthing a direct lighting strike. Otherwise all household appliances (even the dishwasher) remains at risk.

Lightning does weird things because so many forget even basic electrical concepts taught in public school science. Once inside a house, a surge will hunt for earth destructively via appliances. Therefore protection starts with the item that harmlessly absorbs hundreds of thousands of joules.

How far is any one protector from that earth ground? That defines your protection.

Now, earth ground defines protection during each surge. The entire system life expectancy is mostly determines by its weakest point - the protector. A minimal 'whole house' protector for AC electric starts at 50,000 amps. Because protection is about earth all destructive surges including a most typical one - direct lightning strikes.

Protection is not about a protector. Protection is mostly about the 'art': single point earth ground. That (geology, connections to it, etc) should be most of your questions. One protector or 1000 - does not matter. A protector is still only as effective as its earth ground.
 
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Old 07-17-12, 02:33 PM
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Lightning doesn't even have to hit your home to cause damage. The Rf from a nearby strike can induce current in the wiring in your walls. That is why that it is still important to use local surge protection on your electronics even when you have a whole house surge protector in the panel.
 
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Old 07-17-12, 02:46 PM
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> The Rf from a nearby strike can induce current in the wiring in your walls.

That explains why every car radio, every cell phone, and every wrist watch is destroyed with each nearby strike. That energy only exists when the claim comes without numbers.

Well, lightning struck the building’s lightning rod. That was maybe 20,000 amps on a wire that was only four feet away from an IBM PC. The PC was destroyed? Of course not. The PC did not even blink. Because induces field damage is a popular myth. Created because the observer did not first learn fundamental principles. Did not learn why that appliance was a direct strike.

More numbers. A long wire antenna is designed to maximize all field energy into the attached radio. A lightning strike was only thirty feet away. That creates thousands of volts on the antenna’s lead.

So we connect an NE-2 neon glow lamp (as found inside lighted wall switches) to that lead. A less than one milliamp through the NE-2 bulb means thousands of volts were now only a few tens of volts. Many will hype the thousands of volts rather than learn even a neon glow lamp(less than one milliamp) makes that induced surge irrelevant.

Three examples of how the mythical nearby surge is only a myth generated by speculation.
 
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Old 07-17-12, 04:14 PM
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What about whole house surge suppressor (we don't have one).
Whole-house surge suppressors are great - we have one and so do a lot of my customers - now. That said, they can only do so much. I would add the one that's made for your panel, but I'd also test the earth ground - the grounding electrode conductor - and all the bonding through to the panel. That's your first line of defense against lightening.
 
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Old 07-17-12, 05:10 PM
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Westom, could you explain why people (and livestock) 20 ft away from a lightning strike to a tree or the ground suffer electrical burns and electrocution injuries? I know it's not from induced voltages...but how does that happen?

If the "bolt" strikes ground...shouldn't that be the end of it?

We aren't talking EMP here...


Also...just curious...did/do you teach at the academy?
 
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Old 07-17-12, 06:22 PM
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I believe Dr Mary Ann Cooper described how sleeping campers were harmed when lightning struck a nearby tree. Those camper sleeping pointed at the tree required emergency medical treatment. Others sleeping perpendicular were unharmed.

Lightning is a current that exists simultaneously everywhere between that cloud and distant charges. If a current flow through a tree, the same current is in the ground beneath campers. But a shorter electrical path to charges (maybe miles from the tree) were into a camper's head and out his feet. Those campers had lightning passing through their bodies.

In another event, some golfers were waiting out a thunderstorm in a shed. Lightning struck nearby earth. Many golfers suffered from the direct strike.

Best is to stand with feet together. Make a single point earth ground. Then a lightning strike need not travel incoming on one leg and outgoing on the other. Even better, the shed should have been encircled with a buried ground loop.

These examples also explain why a horse some 20 feet from a struck tree was also part of the direct lightning strike.

Same protection for any animal is also how homes get protected. Single point earth ground. So that current need not be both incoming and outgoing through an animal or through household appliances.

View the entire current path. It includes a cloud, three miles of air down to the tree, and maybe four miles to distant charges via earth. Anything making a single point ground (ie surrounded by a buried ground loop) would not be in that current path. Also explains why earthling so critical for barns.
 
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Old 07-17-12, 07:06 PM
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You may want to have the wiring in the house meggered to see if there is any hidden damage.
 
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Old 07-18-12, 08:27 AM
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Westom ...

Last evening I dug up around the ground rod. We live near the coast. The house is located 5 feet above the water table. The ground rod is possibly 8 feet long.

Here is what I found:

Electrical - The wall-box is 6 feet from the ground rod. There is very thick ground wire that goes from the box to the foundation and then bends back up to clamp to the rod (like a U-shape). The clamp was loose and in bad shape. Replaced with new clamp. Should I be concerned about the bends?

Cable - The wall-box is 5 feet from the ground rod. There are two splitters inside the box. There are two sheathed ~12-14 gauge ground wires that goes down a non-metal conduit and into a clamp at the foot of the foundation. There are 90 degree bends. From the clamp another ~12-14 wire goes to the ground rod. I removed, cleaned and re-secured the clamp.

Telephone - The wall-box is 4 feet from the ground rod. The ground wire appears to go down to the foundation behind and under a pipe and finally clamps to the ground rod. There are 90 degree bends. I removed, cleaned and re-secured the clamp. It was getting dark so I could not investigate the pipe that runs across the foundation. Will do so today.

For all three above, using a multimeter and verified connectivity between the wall-box ground wire and the ground rod.

westom > How far is any one protector from that earth ground? That defines your protection.

Given the proximity of the electrical ingress wall-box to the ground rod ... its probably prudent to install the protector there. correct?

Is there anything else I need to check. How do I check the house wires for damage?

I have an electrician scheduled to come tomorrow. I may ask him to install the protector. Is there anything else I need him to address?

Thanks all ... its been a learning experience for me !!!!
 
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Old 07-18-12, 08:53 AM
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Ground wire to foundation may be an Ufer ground. One of the best grounds. Pioneered in munitions dumps to avert lightning damage.

Better though is to have a dedicated wire from the box to the earth ground rod without that bend (especially if it is not an Ufer ground). Good is to have a suspected Ufer ground and ground rod interconnected. It makes an even more robust single point ground. Also good is that every ground wire is separate until all meet at the single point ground - that 8 foot electrode. As you have described for phone and AC grounds.

Your ground connections sound like they are as short as possible. Try to eliminate all sharp bends by making any connections straighter. Or by changing bends into long sweeping curves at least 12 inches radius.

Best is to route those ground wires away from other wires. And for the TV cable wire after the ground connection to be separated from the TV cable wire before the earth ground connection.

It sounds like a 'whole house' protector in the breaker box would make a sufficient connection to earth.

BTW, consider adding a second (or more) ground rods. Code says how apart each rod must be located. Also important - each rod must be firmly attached to earth. For example, a loose rod suggests a previous strike was via soil that was not conductive enough. A loosening that would not happen if more rods were making that earth connection. You did not say you had that or some other things. But those warnings included just in case.

Good is that inspection that located a loose clamp. It was important for your 'secondary protection layer'.

While at it, also inpsect your primary protection layer. A picture demonstrates what to inspect:
Florida Power & Light and BellSouth
 
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Old 07-18-12, 09:05 AM
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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://www.eeel.nist.gov/817/pubs/sp...%20happen!.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

The IEEE surge guide is aimed at people with some technical background.


westom wrote:
"Nothing inside can do useful protection."

Both the IEEE and NIST surge guides say plug-in protectors are effective. 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.


westom wrote:
"Had a surge been earthed at the service entrance, then protection already inside every appliance would not have been overwhelmed."

Some equipment has surge protection. Some does not.

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

Service panel suppressors do not, by themselves, prevent high voltages from developing between power and phone/cable/... wires. The NIST surge guide suggests most equipment damage is from high voltage between power and signal wires. An example of where a service panel protector would provide no protection is the IEEE surge guide example starting page 30.

But service panel protectors are very likely to protect anything connected only to power wires from a very near very strong lightning strike. They may or may not protect equipment connected to both power and signal wiring.


The author of the NIST surge guide looked at the surge current that could come in on residential power wires. The maximum with any reasonable probability of occurring was 10,000A per wire. That is based on a 100,000A lighting strike to a utility pole adjacent to the house in typical urban overhead distribution.

Recommended ratings for service panel protectors is in the IEEE surge guide on page 18. Ratings far higher than 10,000A per wire mean the protector will have a long life.


With no service panel protector, and with a strong surge there is arc-over from the service panel busbars to the enclosure at about 6,000V (US). The established arc voltage is hundreds of volts. Since the enclosure is connected to the earthing system that dumps most of the surge energy to earth.

For a direct lightning strike to the building lightning rods are required. (Not obvious if there was a direct strike.)


westom wrote:
"Effective solutions have the one and critically important requirement. A wire that must be connected low impedance (ie 'less than 10 feet') to earth ground rods."

Ground rods are lousy earthing electrodes. The US NEC only requires them to have a 25 ohm resistance to earth. Or use 2 and there is no resistance requirement. If you connect 120V to a code compliant 20 ohm rod you get 6 amps.

If you have a 2,000A surge curretn to the earthing system and the resistance to earth is a very good 10 ohms, the building 'ground' system rises to 20,000V from 'absolute' earth potential. If the earthing system is a ground rod, in general 70% of the voltage drop away from the rod is in the first 3 feet. The voltage between the building 'ground' system and earth more than 3 feet from the rod is 14,000V or more.

Much of the protection is that all wiring in the building rises together. That requires a short ground wire from entry protectors to a common connection point on the power earthing system. An example of a ground wire that is too long is in the IEEE surge guide starting page 30.

The author of the NIST surge guide has written "the impedance of the grounding system to `true earth' is far less important than the integrity of the bonding of the various parts of the grounding system."

If the system is earthed then worry about the length of the ground wire from cable and phone entry protectors to the common connection point on the power earthing system.


westom wrote:
"Cable needs no protector. Cable connects to earth by something even better than a protector. A wire."

"Needs no protector"? The code just requires a ground block that allows the coax shield to be earthed.

The IEEE guide says “there is no requirement to limit the voltage developed between the core and the sheath. .... The only voltage limit is the breakdown of the F connectors, typically ~2–4 kV.” And "there is obviously the possibility of damage to TV tuners and cable modems from the very high voltages that can be developed, especially from nearby lightning."


westom wrote:
"You do not yet have properly earthed 'whole house' protection. If you had, then all appliances would have been protected."

Not necessarily.

For example a pad mounted compressor/condenser (as noted in the IEEE surge guide). The compressor is at earth potential at the pad, which in the case above can be over 14,000V from the building ground system. The wiring is near the building ground system. The power ground wire to the compressor does not necessarily help. Surge currents have relatively high frequency components. That means that the inductance of the wire is more important than the resistance. (A 30 foot wire in the IEEE surge guide example has 10,000V end-to-end.)

You can get the same effect with a very near lightning strike, where the pad and earthing system are at very different potentials.

Another example is direct pickup from a near strike as in a post from drooplug. This is in the NIST surge guide (page 14).
 
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Old 07-18-12, 09:10 AM
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Westom .. thanks again !!!

The house is 16 yrs old and one of many homes built in a huge subdivision. I doubt the builder would have bothered with an Ufer ground.

Thanks !
 
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Old 07-18-12, 09:29 AM
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bud wrote:
Q - Will a surge protector installed at the service entrance be sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances [electronic equipment], No for two-link appliances [equipment connected to power AND phone or cable or....]. Since most homes today have some kind of two-link appliances, the prudent answer to the question would be NO - but that does not mean that a surge protector installed at the service entrance is useless."
Bud,

Good info. Most of the devices that got damaged in that lightning strike were ones that had multiple links. The TV was connected to power + cable TV + CAT5 network. The wireless router also got hit even though it had only power + CAT5 (no cable TV).

If an electrical surge protector is supplemented by properly grounded cable and telephone (at the ingress) ... would that not help?

I also see that Eaton and Murray make telephone and cable surge protectors (to be installed at ingress).

As far as near-device protection ... I understand the logic of having all links going through the surge protector. Just yesterday, I purchased a Tripp Lite 1000VA UPS from Costco. Aside from power it offered cableTV and phone protection.
 
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Old 07-18-12, 10:10 AM
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Last evening I dug up around the ground rod... The ground rod is possibly 8 feet long.

The wall-box is 6 feet from the ground rod. There is very thick ground wire that goes from the box to the foundation and then bends back up to clamp to the rod (like a U-shape). The clamp was loose and in bad shape. Replaced with new clamp. Should I be concerned about the bends?
No. From your description, it sounds like you should be more concerned about having an effective Grounding Electrode, i.e., an effective path to ground. Standard practice, without testing, is to install 2 copper ground rods 6' apart, with one bare wire connecting both to the service entrance.

The requirement is that there be less than 25 ohms of resistance between the GEC and the earth, IIRC. You can ask the electrician about all of this. The equipment needed to actually test that the resistance standard has been met is very expensive, and not many electricians have it. We just rely on the pair of ground rods and the single conductor to create a grounding electrode that will meet the standard, since that has been found to work in almost every situation.

How far is any one protector from that earth ground?

Given the proximity of the electrical ingress wall-box to the ground rod ... its probably prudent to install the protector there. correct?
I believe the protector you're asking about is a whole-house surge suppressor. They typically mount in the main electrical panel, as close to the incoming feed as possible. See post #18. It is unlikely that your electrician will have the one you need with him unless you tell him that you're interested in having one and tell him the mfr. and model of your panel.

Is there anything else I need to check. How do I check the house wires for damage?

I have an electrician scheduled to come tomorrow... Is there anything else I need him to address?
You may want to have the wiring in the house meggered to see if there is any hidden damage.
See What's a Megger Tester?
 
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Old 07-18-12, 10:11 AM
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Understand that bud only joined because I posted here. He is my personal troll. His job is to promote ineffective and extremely profitable plug-in protectors. Even his own citations say why his protectors are ineffective. "The best protector in the world is useless if grounding is not done properly". Useless. His protectors have no earthing. Will not even discuss it. bud says his protector work by clamping. Clamping to what? Nothing. Energy magically disappears because his protector is clamped to nothing.

An IEEE Standard defines earth protectors as "99.5% to 99.9% protection". Install an adjacent protector for maybe another 0.2% protection. Basically, to protect from surges that do not overwhelm protection already inside every appliance.

bud will not discuss numbers. Only deny them. One 'whole house' protector is essential to even protect a grossly undersized power strip protector. So that even the rare fire created by power strips will not happen.

But again, if his recommendations were honest, then he says where hundreds of thousands of joules dissipate. He cannot. He is a professional sales promoter. Will not even post one manufacturer spec number that claims protection. He cannot. Those numbers do not exist. He will post insults at me. Turn discusson nasty. That has been his history for almost a decade. In all that time, he never once posted even one manufacture spec number that claims protection.

A protector is only as effective as its earth ground. As his NIST citation says, plug-in protectors are "useless". A 'whole house' protector is not perfect. It will only do "99.5% to 99.9% protection".
 

Last edited by westom; 07-18-12 at 10:35 AM.
  #28  
Old 07-18-12, 10:15 AM
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> I doubt the builder would have bothered with an Ufer ground.

In some venues (ie CA), it was required. Probably not in yours. But then an informed home buyer may have asked for it. But yes, an Ufer ground is unlikely.

Nashkat1 has discussed earthing only to meet code. Earthing may also need to exceed code. IOW your ground rods must both meet and exceed code. If grounding is in poor conductive soil (ie sand), then two ground rods might be insufficient. Earthing - not the protector - defines protection. A protector is only as effective as its earth ground.
 
  #29  
Old 07-18-12, 10:55 AM
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I am looking at two whole house surge protectors to mount within outside electric box. Any experienced thoughts:

Cutler Hammer / Eaton - CHSPT2ULTRA
• 20kA (In) Nominal Discharge Current 1
• 108kA Surge Current Capacity Per Phase Rating 2
• *$75,000 Warranty

or the Ditek
Peak - 100KA (20KA In)
MCOV 150/300V

More info here ...
http://www.ditekcorp.com/Docs/ProdGu...0Datasheet.pdf
 
  #30  
Old 07-18-12, 12:17 PM
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I am looking at two whole house surge protectors to mount within outside electric box.
What is the outside electric box? Do you have a main disconnect outside, so that your inside box is a subpanel? If so, how do you propose to connect either of these devices to the feeders running through that disconnect?

Whole house surge suppressors mount in, or adjacent to, main distribution panels, and are mounted or connected to the ungrounded feed buses in the panel, IMX.
 
  #31  
Old 07-18-12, 02:51 PM
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westom,

I had my service entrance upgraded a couple years ago. In that process, two new grounds rods were installed for the service ground. The electrician also took the ground wire from my FIOS box and attached that to the old ground rod. Do you see a problem with that arrangement? The old ground rod is not connected to the new rods at all. I am currently unsure of the distance between the two.

Also, I have an abandoned coax from the cable company that still comes to my house. It is not connected to my house and its ground cable is no longer attached either. Should I get that ground wire properly located on one of the ground rods?
 
  #32  
Old 07-18-12, 07:45 PM
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> I am looking at two whole house surge protectors ...

Cut that coax cable off back at the pole. Or just connect its every wire to earth. In most cases, as is will not be a problem. However better is to eliminate any possible anomaly.

Single point earth ground is critical. Two incoming wires connected to different earth grounds (original and new one) means a surge can even connect from one earth groudn to the other, destructively, via something inside the house.

A utility in Tech Tip 08 demonstrates how to fix earthing when utility wires were previously installed incorrectly. When multiple earth grounds exist. It is a kludge. But it creates what is critical - single point earth ground:
Tech Tip 08 - Indiana Business-Duke Energy

Nashkat1 also discussed some requirements necessary for human safety such as how the protector might be disconnected. An example of meeting human safety requirements while meeting other requirements for transistor safety. He asks questions that your electrician should both ask and answer.

At first glance, both the Cutler-Hammer and Ditek units are 100,000 amp protectors. That number defines protection over many years - after many surges. Minimal protection is 50,000 amps. Do you need 100,000? Well that can only best be answered by neighborhood history and other factors. But in most residential cases, that is better than sufficient.
 
  #33  
Old 07-19-12, 08:22 AM
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westom said:
Understand that bud only joined because I posted here.
Understand that westom googles for "surge" to insert his "wisdom". Part of his "wisdom" is a crusade against the scourge of plug-in protectors. Some of what he says is very good. Some not-so-good. And some is complete nonsense. Everything he says about plug-in protectors is complete nonsense.


westom said:
His job is to promote ineffective and extremely profitable plug-in protectors.
If westom had valid technical arguments about plug-in protectors he wouldn't have to lie about others.

I promote only accurate information. Then people can make appropriate decisions.

A small part of my first post responded to typical westom nonsense about plug-in protectors and westom responds with a rant.


westom said:
Even his own citations say why his protectors are ineffective. "The best protector in the world is useless if grounding is not done properly". Useless.
Both the IEEE and NIST say plug-in protectors are effective.

For example the NIST surge guide says:
"Plug-in...The easiest of all for anyone to do. The only question is 'Which to choose?'"
They are "the easiest solution".
And "one effective solution is to have the consumer install" a multiport plug-in suppressor.

The IEEE surge guide has 2 detailed examples of protection. Both use plug-in protectors.


westom said:
His protectors have no earthing. Will not even discuss it. bud says his protector work by clamping. Clamping to what? Nothing. Energy magically disappears because his protector is clamped to nothing.
Westom appears to have a religious belief (immune from challenge) that protectors must directly earth a surge.

Anyone who can read and think can read the IEEE surge guide (starting page 30) and find out how they work. It is not primarily by earthing a surge. Plug-in protectors primarily work by limiting the voltage from each wire (power and signal) to the ground at the protector. The voltage between the wires going to the protected equipment is safe for the protected equipment


westom said:
An IEEE Standard defines earth protectors as "99.5% to 99.9% protection".
The 99+% figures are in the IEEE "Green" book and are for lighting rods. They have no relevance to surge protectors


westom said:
One 'whole house' protector is essential to even protect a grossly undersized power strip protector.
Complete nonsense.

Just the opposite may be true. One of westom's "responsible companies" - SquareD - says for their "best" service panel protector "electronic equipment may need additional protection by installing plug-in [protectors] at the point of use."


westom said:
So that even the rare fire created by power strips will not happen.
UL has, since 1998, required thermal disconnects for overheating MOVs (the voltage protection elements in surge protectors). Any surge protector in the US should be listed under UL1449. Some UPSs don't seem to be.


westom said:
But again, if his recommendations were honest, then he says where hundreds of thousands of joules dissipate. He cannot.
I often have. But westom ignores anything that does not fit into his limited view of protection. As I wroted in my first post, at about 6kV there is arc-over at service panel busbars with the arc voltage hundreds of volts that dumps most of the surge energy to earth. Then the impedance of the branch circuit to the relatively high frequency surge current components greatly limit the energy that can reach a plug-in protector.

The author of the NIST surge guide looked at the amount of energy that could be absorbed in a MOV in a plug-in protector. Branch circuits were 10m and longer, and surges coming in on power wires were up to 10,000A (which is the maximum probable surge, as in my first post). The maximum energy was a surprisingly small 35 joules. In 13 of 15 cases it was 1 joule or less. Plug-in protectors with much higher ratings are readily available.

(Neither service panel or plug-in protectors work by absorbing the surge. But they both absorb some energy in the process of protecting.)


westom said:
He is a professional sales promoter.
The lie repeated.


westom said:
Will not even post one manufacturer spec number that claims protection. He cannot. Those numbers do not exist.
I have posted specs. Others have posted specs. A 10 year old can find specs. Always ignored by westom.

Apparently westom knows plug-in protectors do not work so specs can not possibly exist.


westom said:
He will post insults at me. Turn discusson nasty.
Westom is "insulted" by the "nasty" facts in the IEEE and NIST surge guides.

{But of course calling someone a company stoodge is not nasty.)


westom said:
That has been his history for almost a decade.
I first saw westom far less than 10 years ago.

But westom has been posting this drivel for 10 years?


westom said:
A protector is only as effective as its earth ground.
Airplanes regularly get hit by lightning.
Are they crashing?
Do they drag an earthing chain?
Is it only 10 ft long?

============================
A concrete encased earthing electrode, commonly called a Ufer ground, has been required by the NEC for maybe 10 years where there is a footing or foundation.
 
  #34  
Old 07-19-12, 08:26 AM
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vulcanman said:
If an electrical surge protector is supplemented by properly grounded cable and telephone (at the ingress) ... would that not help?
Entry protectors for cable and telephone (and dish) are required for surge protection. They are also required by the NEC, so they should be there. Existing telephone protection is almost always good. Cable is usually earthed properly. Dish is sometimes earthed properly. As in my first post, the entry protectors for coax do not limit the voltage from the center conductor to shield. I would use a plug-in protector on high value TV/related equipment, and that would protect the center conductor.

The wires from entry protectors to a common point on the power earthing system should be short. Sounds like yours are. I would almost always connect entry protectors to the wire to the earthing electrode system.

Sharp bends in wires increase the inductance. Gradual bends, a few inches radius, are OK.
 
  #35  
Old 07-19-12, 08:30 AM
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drooplug said:
I had my service entrance upgraded a couple years ago. In that process, two new grounds rods were installed for the service ground. The electrician also took the ground wire from my FIOS box and attached that to the old ground rod. Do you see a problem with that arrangement? The old ground rod is not connected to the new rods at all. I am currently unsure of the distance between the two.
It is a NEC violation to have earthing systems that are not bonded together.

I posted an example of a 2,000A surge current to earth that resulted in the earth over 3 feet from the ground rod being at least 14,000V from the building 'ground' system. Your FIOS box can be thousands of volts from the power system ground. If the rod is bonded to the power earthing system the impedance of the wire to relatively high surge current frequencies can prevent it from doing much good. Separate earthing electrodes are looking for trouble even when they are bonded properly. With few exceptions you bond the earthing electrodes and then make a single connection to the earthing system for all the wiring.


drooplug said:
Also, I have an abandoned coax from the cable company that still comes to my house. It is not connected to my house and its ground cable is no longer attached either. Should I get that ground wire properly located on one of the ground rods?
Yes.
 
  #36  
Old 07-19-12, 09:45 AM
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OK, guys - I think we've beaten this dead horse enough
 
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