# Plastic / electrical smell after breaker trip



## adgjqetuo (Oct 21, 2011)

I was using my chop saw and right when I pulled the trigger the breaker popped. It's happened on a rare occasion before so I went to reset the breaker. When I went to the box to reset it, I immediately smelled a plastic / electrical smell coming from the panel. I reset the breaker, continued with my cuts and a few minutes went back and I didn't smell anything.

Should this be cause for concern?


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## Doc Sheldon (Nov 23, 2014)

If what you smelled was burning insulation, I'd say it should be checked out by an electrician. It could be just a loose connection, or possibly some damaged insulation that allowed an arc. But if you think it smelled like burning plastic, I wouldn't ignore it. I'd stop using any receptacles on that circuit until it's been checked out.


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## adgjqetuo (Oct 21, 2011)

It wasn't burning insulation - it smelled more like plastic


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## Doc Sheldon (Nov 23, 2014)

when I refer to insulation, I'm talking electrical insulation, not thermal. The insulation on wiring is typically a polymer (plastic)...


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## Jump-start (Sep 26, 2012)

Could be just from the breaker tripping on a fault, but seriously Id be just as concerned if not more on why the saw is tripping the breaker.


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## adgjqetuo (Oct 21, 2011)

I took off the panel (never did before) and everything looked clean and neat. The breaker that tripped (and all others) looked completely fine. No signs of heat on the wires (copper looked normal color).

The saw is a 15a chop saw on a 15a circuit of 5 outlets in my basement. My surround sound was playing the radio and I also have a chest freezer on the circuit. I'm wondering if the freezer tried kicking in just as I started the saw.


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## Jump-start (Sep 26, 2012)

adgjqetuo said:


> I took off the panel (never did before) and everything looked clean and neat. The breaker that tripped (and all others) looked completely fine. No signs of heat on the wires (copper looked normal color).
> 
> The saw is a 15a chop saw on a 15a circuit of 5 outlets in my basement. My surround sound was playing the radio and I also have a chest freezer on the circuit. I'm wondering if the freezer tried kicking in just as I started the saw.


Any pictures just to confirm? Not that I don't trust you but its just good to have an expert opinion 

The freezer kicking on just as a saw that fully loads the circuit being switched on could cause a breaker to trip.


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## adgjqetuo (Oct 21, 2011)

Sure - see below. The one that tripped was the last one on the bottom left.

Side note - does anyone know why my smoke alarm circuit has a black into the breaker and a red going from the breaker into the ground bar? (Last picture)

All circuits to my knowledge (I'm the second owner) are original from the builder except the last two on the left and the last one on the right which feed the finished basement.


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## Jump-start (Sep 26, 2012)

All looks good from here. No signs of overheating.

Those are square D QO which tend to have a low magnetic trip point on single pole breakers. That simply means they are more likely to trip on motor inrush. If the saw and freezer started at the same time the combined inrush current from both motors tripped the breaker.


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## Desertdrifter (Dec 10, 2009)

Look at the 2nd breaker on the right with the red. I see an annealed screw head. Looks like it was hot from what I can tell.

Double stabbed? Unless its made that way.


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## adgjqetuo (Oct 21, 2011)

The second one on the right is my dedicated smoke detector circuit. I can't imagine that bring under any type of high load. 

I don't understand why it has a black and a red wire into the breaker either. It's the only breaker like that. 

The alarms all function properly though.


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