Checking House Ground/Lightning protection

[James "Cubby" Culbertson]

Hiya, My sister recently had a bolt of lightning hit very near to her house. She lost a number of electronic appliances as a result. My initial thought is that she may not have a good ground for her house. I'm wondering if there is a way to test it or is it mostly just a visual thing? As well, are whole house surge protectors good for this type of application? I suspect not but thought I'd ask. I'm in a high lightning area (2nd highest number in this state, FL is no. 1) and really don't have any trees nearby so I'm beginning to think maybe a separate ground system just for lightning protection might make sense. Obviously I'd locate the ground rod as far away from the house ground but I'm wondering if this makes sense? Cheers, cc

[gfretwell]

Surges that blow up electronics will not be stopped by a lightning rod system. The first thiung you have to do is fix your house grounding system. Make sure you have a solid ground electrode system. That will be metal water piping, within 5 feet of entering the house, supplimented with at least one ground rod or other electrode. This gets connected to your power panel grounding bus (although it may really land in the meter). The next thing you have to do is be sure the telaphone and cable company is bonded to your ground electrode system, They should have protectors in their Dmark and you should have a whole house protector in your panel. If you are really in a lightning area I would also advise point of use protectors at your TV, Computer and whatever else you want to keep, particularly the stuff with more than one cable going into it. Make sure your point of use protector catches all of those cables (TV, phone and power).

[m Ransley]

As ghetwell said you should go over everything, even test outlets to be sure they are wired properly. After I was hit a few times and loosing tens of thousands in electronics I put in a panel Lightning arrestor, panel surge protector, and individual outlet supressors. But dont buy the cheap HD stuff, there are ratings on their worth, such as nanosecond clamping time and product warrantys on lightning protection. Look at Trip Light, they have good products that work quick, absorbe a fair amount and have a lightning warranty. But no matter what you do lightning can bypass all but the best commercial equipment set ups, even the air charge can blow out equipment. Your best habit is unplugging what is sensitive or have a switched outlet on specific areas you want to protect and use surge protection

[hallerb]

main house ground MUST be bonded to lightning arrestor ground, the kind that has wire on top of home to dissapate strikes. install main service panel surge protection for sure, those cheap terminal strips are just that cheap wanabee junk.

if you have anything really sensitive plug into UPS, some come with a complete warranty to cover anything that gets zapped.

no matrtewr what you do lightning will fry stuff if the hit is close enough.

make certain cable, satellite, phone, power panel, and everything else are firmly tied together.

otherwise a close hit can kill! by disimmiar ground voltages

[Pop]

A good resource is your local code enforcement office. We learned the hard way that a lightning hit, IF it uses the house wiring to get to earth, or vice-versa, can cause the earth rod to lose its conductivity to earth. Apparently it affects the earth for a radius ofa 6 or 8 feet or so because they moved our ground rod about twelve feet over and drove a new one. We wouldn't have noticed it except for 220V equipment that started acting up due to the lack of a good earth ground reference between the two 110 "phases" (US). The new rod fixed all the problems. Our local code enforcement is the one referred us to a good electrician who came out and figured it out in about 5 minutes. That was after three guys from the yellow pages who were just "electricians"; this guy was an inspector and knew what to look for apparently. The only thing he charged us for was the rod and some cable to the meter. The other folks wanted to start tearing things apart. I'm glad I resisted.

HTH Pop

[Pete C.]

A lightning strike could well affect the soil conductivity around the grounding electrode(s) aka ground rods, but that will not cause problems with 220V appliances. The ground is *not* the reference for the 110V power, the neutral is and that comes from the distribution transformer on the pole (or pad). The ground and neutral are bonded at the service panel, but the ground is *not* a substitute in any way for the neutral from the transformer.

Pete C.

[James "Cubby" Culbertson]

Ok. So now you've got me thinking a bit here. On my sister's house, she's connected to city water and I've not looked to see where the pipe enters from the street vs. where the electrical service/ground is. Would the best bet be to tie the two together assuming she has a dedicated ground near the meter? Obviously, if the two were close together, this wouldn't be a good thing. On my house, I'm on a well and the pipe coming in is approx. 15 feet or so from the rod driven into the ground near the meter. My gas supply/meter is very near that water line. Would it do any good to connect the dedicated ground to the water line that runs out to the well especially being so close to the gas meter? I do plan to upgrade my service and when I do I'll add the whole house surge protector and possibly a lightning arrestor but it appears the best prevention is a good ground. Thanks for the advice. Cheers, cc

[Pop]

Hmm, you're right, of course. I think, logically anyway. Maybe he did more work than I realized or was aware of, but ... .

If there was no earth, it would float, and since it's tied to Neutral in the box ... and since the transformer's ... ouch; brain ache! The problems were apparent out in the barn, about

100 ft away from the box. House itself didn't show Neutral problems per sae, but the air pump & water pump would show up in the house incandescents but not wildley; Oof! I quit!

O well! Pop`

[Bud--]

The best information I have seen on surge protection is at

the title is "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits"

- it was published by the IEEE in 2005 (the IEEE is the dominant organization of electrical and electronic engineers in the US)

A second reference is

this is the "NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home"

- it is published by the National Institute of Standards and Technology, the US government agency formerly called the National Bureau of Standards in 2001

Both guides were intended for wide distribution to the general public to explain surges and how to protect against them. The IEEE guide was targeted at people who have some (not much) technical background. Read one (or both) to understand surges and protection.

Includes service panel protector, plug-in protector, system ground, single point ground.

Note that when using a plug-in surge suppressor and a device, like a computer, has connections other than power, like a phone line, they have to be connected through the surge suppressor also. This type of suppressor is called a surge reference equalizer (SRE) by the IEEE (also described by the NIST). The idea is that all wires connected to the device (power, phone, CATV, LAN, ...) are clamped to the common ground at the SRE. The voltage on all wires passing through the SRE to the protected device are held to a voltage safe to the device.

bud--

[Member, Takoma Park Volunteer]

I built radio equipment shelters for two years. Our shelters were struck many times without any damage to the equipment inside. Lightning damage is not inevitable. You just have to be willing to invest the effort to install effective protection.

[loononastick]

My house was hit by lightning back in 48. Everyone that lived there was killed. I still recall my own funeral was held 3 days later, because my penis exploded from the overheated urine, and aunt Gertrude's breasts exploded from pressure of the the boiling milk. It was horrible to see. The insurance adjuster blamed the deaths on the lightning bolt. It turned out the lightning bolt was not grounded. God was charged with murder and found guilty. They are still trying to get him in prison but he always escapes the second they capture him.

[James "Cubby" Culbertson]

Oh why don't you just get a life!!!