Lightning Damage

[mkgrady]

I'm going to look at a customers house that had a problem with lightning and he wants everything checked out and fixed. He reports his security alarm system was blown and has been repaired. He claims there are several receptacles that do not work and some light fixtures that do not come on.

He claims that his insurance will cover all costs. Other than making the dead outlets and light fixtures operative, what is involved in checking the house wiring to be sure he gets everything fixed that may have been damaged?

 

[cowboyjwc]

I would probably megger out the whole house if you're not positive what was damaged.

 

[ceb58]

I would probably megger out the whole house if you're not positive what was damaged.

And make sure he pays you. Let him turn the invoice in to the insurance company himself for reimbursement.

 

[mkgrady]

I would probably megger out the whole house if you're not positive what was damaged.

Is the theory that some of the wire insulation was damaged by spikes in voltage? If a circuit fails a megger test is it likely the whole circuit should be rewired? To meggar test a circuit what precautions do I take besides making sure everything is unplugged from receptacles?

 

[satcom]

Lightning damage can cause some strange conditions which may not be detected with a meager, often NM cable can be blown apart in a wall, if you opened the wall the NM would look like a spent firecracker in the damaged sections, but could still pass a megger test, we found a flex fiber camera feed thru the wall at small sections will reveal cable damage concealed in the walls, it takes time but, even a near hit can cause some serious damage behind the walls. The fiber cam is the least destructive method, but also run the meager test.

 

[mkgrady]

Lightning damage can cause some strange conditions which may not be detected with a meager, often NM cable can be blown apart in a wall, if you opened the wall the NM would look like a spent firecracker in the damaged sections, but could still pass a megger test, we found a flex fiber camera feed thru the wall at small sections will reveal cable damage concealed in the walls, it takes time but, even a near hit can cause some serious damage behind the walls. The fiber cam is the least destructive method, but also run the meager test.

So, would I have to use my tracer to detect where every cable goes, and then make a hole between every stud or ceiling rafter to look for charred romex jackets? Sounds like that could take days to do, not to mention having the peep holes patched and painted.

 

[cowboyjwc]

I agree with the others that they could be some unseen damage, but then again there may not be any thing more than it blew out the recepts.

We had an incident here where a 14k transmission line fell and landed on the SE wires going into the house. It literally blew the meters off of two houses. My boss told me to go check the houses and see if they could be safely turned back on. I asked him how the heck I was supposed to do that? They needed someone to come in and check out the whole system. Total damage was the meters, a couple of GFCI recepts, and some electronics in one of the two houses.

 

[satcom]

So, would I have to use my tracer to detect where every cable goes, and then make a hole between every stud or ceiling rafter to look for charred romex jackets? Sounds like that could take days to do, not to mention having the peep holes patched and painted.

We look for signs of more serious damage with a good visual check of the open areas before we start looking in the walls. I will look for the pic's of the type of damage you may find

 

[mkgrady]

We look for signs of more serious damage with a good visual check of the open areas before we start looking in the walls. I will look for the pic's of the type of damage you may find

Thanks, I'd like to see them.

 

[Fulthrotl]

I'm going to look at a customers house that had a problem with lightning and he wants everything checked out and fixed. He reports his security alarm system was blown and has been repaired. He claims there are several receptacles that do not work and some light fixtures that do not come on.

He claims that his insurance will cover all costs. Other than making the dead outlets and light fixtures operative, what is involved in checking the house wiring to be sure he gets everything fixed that may have been damaged?

digital megger like the fluke would be a good place to start... i'd set it for 250 volts,
unplug everything, and check everything phase to phase, to neutral,
and to ground. after i knew both sides were ok, i'd turn on the burners on
the range if it's electric, and check both legs to ground.

this'll tell you if the thing will hold electricity or not. then a good visual for
any burn or smoke, etc.

as for looking inside walls to inspect, how far that went would depend i
guess on what kinda megger readings i got... i'd do a good inspection
in the attic to see what the romex looked like up there, before i
started cutting holes in the walls...