Flash, pop, no more GFCI receptacle!


  #1  
Old 06-01-08, 08:05 PM
Z
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Flash, pop, no more GFCI receptacle!

I’m no electrical guy but I’ve installed many light fixtures, switches, and receptacles in my house and never had a problem. But a 15 amp 120v GFCI receptacle I installed in my garage went flash, pop, tripping the circuit breaker when I plugged in an extension cord connected to a drop light. After that I could not reset the circuit breaker or the GFCI receptacle. I had been using the new receptacle on and off for weeks.

I know I did something dumb but I don’t understand why it would have ruined the receptacle. Maybe it had nothing to do with it. For some reason the plug on the drop light was very hard to plug into the extension cord this time? I pushed it in with force (I know – DUMB). The GFCI tripped when I turned on the light. I reset the GFCI and tried it again (I know – even DUMBER). This time I got a flash, pop, and never could reset the circuit breaker after that – even after first pushing the reset button on the GFCI before trying to reset the breaker.

I looked in the receptacle box and the hot,neutral, and ground connections all still looked OK, however the hot brass screw on the receptacle was blackened. I changed the box from metal to plastic, got a new GFCI, and it’s fine. Extension cord and drop light also seem fine ?– but who knows?

I’d really like to know what could have possibly happened here so it never happens again. Flash and pop seem very dangerous to me! What causes a hot connection on a receptacle to overheat and what could have ruined it? I thought GFCI protected itself? I did find a nick down to copper in the neutral wire in the box. It’s possible I might have done it when pushing in the new receptacle. It was a very tight fit even though only one cable entered the box and it connected to the old duplex receptacle. It was an old metal box and the GFCI receptacles seem exceptionally deep.

So this time I got a bigger box made out of plastic, cut back the neutral wire past the nick, and put in a new GFCI receptacle. I was then able to reset the circuit breaker immediately. Everything seems OK? Could a nick in the neutral wire have caused the problem?

Any thoughts would be greatly appreciated!
 
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Old 06-02-08, 03:55 AM
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Sounds like the brass screw was close enough to the metal box or another grounded surface that caused a short circuit.
 
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Old 06-02-08, 06:03 AM
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Thanks a lot pcboss!

You got me thinking. Things were so tight in the box, I wonder if my ground wire was a little too long and got pushed over almost to the brass screw when I pushed the receptacle back in the box? I’ll bet that could have happened and everything would still look connected properly when I pulled the bad receptacle out a little to inspect everything in the box. I think I do remember getting a little long on the ground wire. That seems to me like it would explain the type of short you describe .

(I’ll never use a tight box again. I figured it must have been within code since it had only one 14-2 w/G cable and one dual receptacle. But the GFCI was deep and I should have changed the box right away.)

Thanks again!
 
 

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