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Smoking GFI outlet in shop

2718 Views 27 Replies 17 Participants Last post by  Dark_Lightning
I was happily working away yesterday when I turned on the planer. Suddenly the power went out and I smelled smoke, burning plastic. The GFI outlet that didn't have anything plugged into was all black I took off the cover plate and it was a melted mess. Why would this happen? The outlets in my shop are 20 years old. I'm going to replace it today, but I would like to get to the cause of the problem, so I don't burn my house down.
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I have never encountered that…I have had them go bad and not function. Is the outlet for the planer wired to the GFI? You could be pulling to much amps thru the GFI.

I would check and make certain the circuit breaker is properly sized and OK. When you replace it check wires for damage. Also use a plug in outlet checker to assure it is wired right.

I would put a smoke detector in your shop for awhile and turn the breaker off for awhile when you are not in shop.

If you can not figure it out you may want to hire an electrician, It would give you some peace of mind.

Good luck
Yes the planer is on the same circuit as the GFI outlet but plugged into another outlet.
That GFI outlet is then failing. I ran into the same problem, only the GFI in the bathroom was only giving half voltage. In depth investigation revealed a bad neutral (on the same circuit) at an outdoor receptacle.
I had a 20 amp GFCI outlet go crispy on me. It fried the plug on an electric heater that was set to very low, with nothing else on. I don't really know why it did it other than it was older.

If the insulation on the wire in your box is melted at all you can get color coded heat shrink tubing to fix it. Your outlets should be tied into the circuit with pigtails, not the LINE/LOAD method of connecting. That way you can eliminate other boxes on the circuit as a cause if something fails.
The GFI is probably wired so that it protects down stream outlets. If so, the current for the planer is going thru the GFI.
Thanks for these answers, I've certainly learned from the replies.
Yes, Redoak that is the situation, the planer is downstream from the GFI. I had the ambient air cleaner running and I had a battery maintainer running on an outside socket on the same circuit at the same time as the planer. Here is a picture of the damage.
Gas Cable Auto part Electronics accessory Telephone


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My GFI outlets in the shop have failed also - but not burned.

They generally begin to hum all the time and pass low voltage downstream.

After replaceing a couple, I got rid of at least 2 of them.

We had a freezer on one that kept tripping for no apparent reason - causing great distress at the prospect of ruined food.

I'm not convinced that these things add anything to safety - esp when powering motors.


Good that you were dodged the bullet on what might have been a much more serous situation!

Looking at your picture raises a question in my mind. The charring all around the connector suggests arcing there, on the outside of the GFI. Perhaps it was a poorly seated connection that developed resistive heating under the load and not an internal failure of the GFI.
Here's the update. I replaced the GFI outlet and I also replaced the breaker w/ a AFCI breaker. I inspected all of the other outlets for potential problems, signs of heat, etc., didn't find anything. I went back to work and finished my planing w/o any further problems. This is one of the reasons I am going to build a new shop next summer. The wiring in the garage is woefully inadequate.

Ocelot, I once lost a freezer full of food for that same reason. That circuit is no longer GFI.
I'd be careful with those arc fault circuit interrupting breakers, many of them don't like running universal motors as the brushes running on the commutator is constantly creating hundreds of arcs per second.
We had one in the kitchen go bad. It too got hot, but still functioned. I found melted plastic when I pulled it out to replace it. That one had a food processor working off it, but I don't know whether that is a universal motor. Induction, I think, but possibly not.

I've had brand new ones bad right out of the box, and those aren't from the BORG. But I think they are all from China now.
Thanks for the great information. I'm always looking for fresh ideas and can't wait to give some of these a try. Personally, I like to take cheap or free wood and "reclaim" it into cool woodworking projects, like island counters, tables, etc.

loiey =)
The food processor almost certainly has a universal motor. The only motorized portable kitchen appliance I can think of that would have an induction motor is a bread machine and that might not be true of all of them, just the ones I've had apart.
I think there is a recommendation to replace all outlets, switches as well as water valves, etc., every 5 years. Not that I follow it, just saying.
Makes you wonder, how is it that appliances from 1950's still run, but modern ones last a few months after the warranty runs out?
I had the same problem with a gfi in the bathroom. They used the push in connection and the wire was loose. It was fried around the hot and intermittently tripped a few times before I pulled it out to figure out what the issue was. Makes me glad I wrapped the wire around screws for all the outlets I have wired.
Here is a picture of the damage.
Gas Cable Auto part Electronics accessory Telephone

- bondogaposis
Loose connection caused by not being quite tight enough when it was installed or loosening due to expansion and contraction over time. I've see it a million times in the last 45 years; well, maybe not a million, but a lot ;-)


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I had a GFI do the same thing but didn't burn the wires though. It just smoked some and blackened the faceplate. It was 14 yrs old and just gave it up. I replaced it and moved on. All OK now. I had another GFI for an outside outlet just fail, also 14 yrs old. I guess they get weak and give out, who knows? I just replace them (not cheap!) and move along. I keep a spare in the shop for the next one that gives it up.
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