Light switch arc

[j2020]

Any guesses what could cause the load arc on multiple light switches? It did not occur at once. Other than bad/worn out contacts, can anyone think of other reasons why the arc occurred on the light switches? Thanks.

 

[mopowr steve]

Lightning strike for one, especially with the amount of carbonization around that area. Unless a high line got into secondary.

Ohhh wait a minute, I just noticed that dimmer is for 0-10volt use, I wonder if your really trying to just dim a regular 120 volt lighting circuit. With that amount of black soot it looks like the electronics grenaded.

 

[mopowr steve]

Any updates on what you found?

 

[Little Bill]

I had something similar on a service call. The HO said it was storming and they heard a loud boom. Some breakers tripped and these switches were smoking out around the wall plate.

 

[hbiss]

Any updates on what you found?

No and my guess is because you were right on the money.

-Hal

 

[ptonsparky]

No and my guess is because you were right on the money.

-Hal

Not doubting his theory, but where did he find it in those picts?

 

[kwired]

is it utilized on 120 or 277?

277 can have more tendency to arc longer once something gets going seen that happen several times, after the fact, often more damage than just the switch or wherever it started as well.

Can't say that for 120, other than in the already mentioned lightning or outside high voltage contact incidents, though the powers that be think AFCI is important thing to have on certain 120 volt circuits.

 

[hbiss]

Not doubting his theory, but where did he find it in those picts?

In the right hand picture, look carefully at the top right of the yoke. It's stamped 0-10.

-Hal

 

[ptonsparky]

In the right hand picture, look carefully at the top right of the yoke. It's stamped 0-10.

-Hal

Figured it was there some where. I couldn't get it to stay focused long enough for these eyes to read.

 

[mopowr steve]

I had something similar on a service call. The HO said it was storming and they heard a loud boom. Some breakers tripped and these switches were smoking out around the wall plate.

I had a lightning strike job some years ago. Now I’ve heard in the past about outlets being blown right out of the wall, on this particular job it was true. It was a switch at the kitchen sink found laying on the floor across the room. And it did some funky thing to the center pin of light bulbs up in the attic where it basically vaporized the terminal and you could look right down into the vacuum tube.