Surge or Lightning

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Little Bill

Little Bill

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Location
Tennessee NEC:2017
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Semi-Retired Electrician
Had a service call today for a supposed lightning strike. HO says a couple of breakers tripped and smoke was coming out of a wall switch. I get there and she has the breakers off. She said if she turns them back on that the smoke starts up again. I took the wall plate off that has visible scorch marks on it inside and out. This was a 2G box with a 3-way switch and a stacked switch. The stacked switch had a 3-way on the top half and single pole on the bottom. Both switches had burn/scorch marks. I checked both the 3-way and stacked switch and only the stacked switch showed bad.

This is strange to me because if it was a direct lightning hit I would think there would be more damage. If it was a surge, I would think it would have damaged the lights or bulbs as well. None of the insulation on the conductors appeared to be damaged, no scorch marks or any sign of them being hot. The HO was preparing for a trip and didn't have time for me to do an insulation test or much further investigation. I did check the panel and didn't see any visible damage there.

One of the switches was for the front porch light and she wanted it to be on while they were away. The other two switches worked a foyer light and upstairs hall can lights. So to give a quick test, I replaced the 3-way that had the burn marks as well as the other 3-way in another location. I didn't have a stacked switch that had a 3-way to replace hers, but I did have a stacked single pole switch. The 3-way portion of the stacked switch was part of a 4-way circuit. So I just tied one of the travelers to the light leg and capped off the other traveler. I used the other part of the stacked switch for her porch lights. I got all the lights back on and watched it for about 15 mins and saw no smoke nor tripping breakers. I told her to just keep an eye on it and leave just the porch lights on when they left for their trip.

Other than a Meg test, I don't know what else I could have done. Thoughts on whether this was a surge or direct hit? There were several storms here last night.
 
I was inside a bathroom of a job site when lightning struck just outside the window. It was the loudest boom I've ever heard, and the brightest flash of light I've ever seen.

The guy homeowner literally screamed like a girl.

There wasn't any damage I found except a couple of receptacles got smoked. No lights damaged, t.v. unscathed, no breaker damage.

I thought at the time there should have been more damage, because I've seen lightning cause more than that. But it's funny like that sometimes, I guess
 
James L said:
I was inside a bathroom of a job site when lightning struck just outside the window. It was the loudest boom I've ever heard, and the brightest flash of light I've ever seen.

The guy homeowner literally screamed like a girl.

There wasn't any damage I found except a couple of receptacles got smoked. No lights damaged, t.v. unscathed, no breaker damage.

I thought at the time there should have been more damage, because I've seen lightning cause more than that. But it's funny like that sometimes, I guess
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The lady did say they heard a loud boom right before the breakers tripped.
 
What does "direct hit" mean? Most direct hits leave obvious damage. Indirect hits to the ground can be analyzed like a big surge from poco.

What brand and type of OCPD's were they?
 
so now carefully de-assemble those yokes, take a look at the insides.
 
DId it arc yoke to yoke, or between screws of each yoke? Was there a EGC on the dual-switch yoke? I wouldn;t think poco would have a surge like that. Any damage in the panel?
 
FionaZuppa said:
DId it arc yoke to yoke, or between screws of each yoke? Was there a EGC on the dual-switch yoke? I wouldn;t think poco would have a surge like that. Any damage in the panel?
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Not sure how it arced, both devices had an EGC. The stacked switch was the only one that tested bad. It also had the most severe burn marks according to the wall plate. No damage (visible at least) in the panel. Only thing not working was the lights that went to these switches.
 
IMHO, there is no EXACT science on lightening hits. Surge protectors help lighten the hit but there's no guarantee. You can install as many lightening arresters and/or surge protectors as you wish but if you get a direct hit - kiss it goodbye.

That said, I had a customer who decided to go out to his mailbox during a lightening storm (didn't ask why). As he opened the front door lightening hit a tree about 50' away from the house. It striated the tree bark on that tree and blew the bark off a tree several feet away. It also hit the wiring for his lawn sprinkler system and blew out the control in his basement. No other damage throughout the house. I told him to go out and buy a lottery ticket. :cool:

Wish I had some advice for your situation but I think you did all the right things so far.
 
My guess is that you didn't have a direct hit to the structure, but rather a nearby strike and the arcing you saw was either from current spreading out in the soil coming in to the house wiring and going out again, or induced current/voltage from the intense magnetic fields.

The most powerful lightning events on Earth produce detectable gamma ray emissions and decay signatures that indicate antimatter production.

Jon
 
winnie said:
My guess is that you didn't have a direct hit to the structure, but rather a nearby strike and the arcing you saw was either from current spreading out in the soil coming in to the house wiring and going out again, or induced current/voltage from the intense magnetic fields.

The most powerful lightning events on Earth produce detectable gamma ray emissions and decay signatures that indicate antimatter production.

Jon
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Does the home have lots of copper pipes, and, all that copper was tied to EGC somewhere?

Sometimes EGC'ing everything can come back to bite ya in the butt. A fully "insulated from earth" wired structured would help guard against stray ground voltage from entering the wiring. As-is, NEC does a good job of "grounding" the util power (service), but this is no good for protecting from nearby lightning strikes.
 
I have lots of elect docs across my PC, ran across this one, a good read. Page 5, they define six different types of lightning issues.
 

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FionaZuppa said:
I have lots of elect docs across my PC, ran across this one, a good read. Page 5, they define six different types of lightning issues.
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Good read. Thank you.

We installed some of these throughout a dairy that was experiencing issues. The dairy owner purchased them. None of us remember now which pilot lights should be on/off or the color. This company felt part of the problem was the Freq Drives used for the vacuum pumps. IDK. It was well above my pay grade. Dairy owner now thinks it was mostly related to a ration change problem and has not worried about them since then.
 
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