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Baseboard heater sparking

Here's a fun Monday night scenario. Just lightly hitting the baseboard heater in the bathroom with a small trash can caused the heater to spark, and not anywhere near the wiring. Removing the cover caused it to do this even more so. This is with the thermostat turned off. The only noticeable sign of a problem is the element sagging. Certainly going to replace it, but I'm just curious as to what is causing this spark, how it's sparking even with the thermostat turned off, etc.? Ever since the second sparking situation we've turned off the power at the breaker :)

Re: Baseboard heater sparking

I suspect the wiring from the breaker and panel go to the baseboard heater where they are spliced under the junction cover and then go to the thermostat and back to the heater

In which case there would be constant power at the heater regardless if the thermostat is off. The thermostat would only control the power to the heating element.

The hot wire's protective cover may be chaffed or the wire nut may have come off allowing the black wire intermittantly touching the the chassis.

Just thought

Re: Baseboard heater sparking

Thanks for reading and taking the time to respond!
My roommate and I took the thing apart last night. He knows a lot more than I do.
More background to this, in case anybody else is ever looking for a similar problem...
The house is older, from the early 70's. The thermostat is on the wall and there's a 240 line voltage through the thermostat which is separate from the heater. It looks like the element was damaged and cracked probably from years of overheating. We assumed that since the thermostat is right next to the door, it can be getting a lot of cold air if the door isn't closed and so is constantly on..In any case, it caused a short to the chassis which we spotted as a nice little burn mark on the underside.
We'll be checking the rest of the heaters for the next couple days!:)
Thanks again. Great community here that I hope to contribute to.

Re: Baseboard heater sparking

Hmmm --- interesting.
The thermostat is basically similar to a light switch ---- when on the contacts close to supply power to the element ---- when off they open to disconnect power.
In other words --- if the thermostat is off there should be no power in the lines to the baseboard heater.

Re: Baseboard heater sparking

Sounds like a job for an electrician, Where's NEC when you need him, LOL :)

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