Another Dead GFCI Outlet

A couple of months ago I was awakened in the night by a loud grinding noise. It was coming from a GFCI outlet in the kitchen of my six-year old home. A fairly new coffee maker, and a somewhat dated microwave oven, had been plugged into the outlet. No breakers had been tripped (though I turned each of them on and off), and the outlet was no longer working. I installed a new GFCI outlet, and all was fine until last night. Again there was a loud grinding noise coming from the GFCI outlet, then a soft pop, and the outlet stopped functioning. What could be causing this problem? Could an idle microwave oven cause two different GFCI outlets to fail?

 

Welcome to the forums! Yes, if there is a ground fault. Leave the appliances unplugged and restore power to the GFCI. See if it happens. Plug the microwave into a different receptacle. Is there any fraying on the micro cord? Has the coffee maker cord been burned?

 

That's exactly why I recommend that homeowners not leave small appliances plugged in when not in use including microwave ovens when going out of town. There are documented cases of small appliances causing fires when not in use. Most small countertop appliances are made in China, many with the cheapest components that can be found. When you leave them plugged in all the time, the Chinese manufactured item becomes a part of your household electrical circuit. If that doesn't make you nervous, it should! Here is a report of a microwave that started running on it's own at night.

Saferproducts.gov | Incident Report Details

If you have access to the March 2012 issue of Consumer Reports, check out the article on page 22 about appliance fires. The article concerns a GE over-the-range microwave that started a fire when not in use. According to the article, there is a class action suit filed in 2009 against GE for these problems.

 

Thank you for the responses. An electrician friend of mine, who lives out of the area, told me he thought it's a wiring problem, and gave me a few things to check. He was talking way over my head, but thought it might be a problem with a neutral shared with another GFCI circuit. Apparently the noise I was hearing was the outlet tripping over and over again.

 

The neutral could possibly be causing a problem, but I know that the GFCI outlet cannot possibly trip over and over again by itself. Once it trips, you must manually reset it before it can trip again.

 

Try plugging the two appliances in elsewhere. If there is no problem with them, you know the problem is probably in the original GFI outlet, or it's wiring. If there is still a problem with either of the appliances or the new outlet they are using, it is time to replace at least one of them.

 

Thanks 1papa. But I replaced the original outlet a couple of months ago, and had the same problem with the replacement. Plugging the appliances into a different outlet and waiting to see if it fails could be a long experiment if it takes a couple more months. Until I can do more investigation, I'm only plugging the appliances into a different kitchen GFCI on an as needed basis.

CasualJoe, maybe "trip" is not the correct word. As I said, my friend was talking over my head, and I wasn't totally following his explanation. But his description seemed to explain the noise I heard on both occasions. It was a repeating, mechanical, grinding sound coming from the outlet, not really an electrical sound. He said it could be something as simple as a loose wire nut on the adjacent GFCI outlet, if it's sharing the same neutral. Unfortunately he lives too far away to do anything more than consult with me over the phone. I'm going to take a look at the outlets and the panel wiring over the weekend when I have more time.

 

I have experience the noise before but from a circuit breaker that was slowly frying. Never tripped but when found, half of it had completely melted from the heat.

 

If you are plugging into another outlet, make sure that outlet is not protected by the faulty GFIC. Most protected outlets are noted on the outlet cover. You can check the protection by plugging in a toaster , activate the toaster then trip the GFIC, if the toaster pops up (de-activates), its protected by the GFIC that you tripped.
I've seen GFIC outlets that protected outlets in other rooms eg: GFIC in the kitchen protected
outlets in two bathrooms.

 

That sound could possibly mean you have aluminum wiring as aluminum wiring can over heat if it doesn't have the correct plugs connected to them marked approved for aluminum wiring. Also the plugs could be incorrectly wired with perhaps the poles in the opposite direction on one of the GFCIs so if I were you I would buy a plug circuit tester that can tell you if everything is correctly wired. Anything incorrectly wired even downstream a bit could cause a fire. If after you have investigated everything to the best of your ability and you still have problems please for your sake play it safe and call in an electrician. Might cost a bit but you would be sure to have everything wired the way you want it and it will be safe.

 

6 year old homes do not have aluminum branch circuit wiring; that isn't your problem.

 

I checked the panel and, as my electrician friend suspected, there's a red wire connected to one of the GFCI circuits, and a black wire connected to the other with a shared neutral. Nothing looked amiss in the panel or in either of the GFCI outlets. I replaced the defective GFCI outlet with a new one, and I'm back up and running again. But I still don't know the source of the problem. Although I'm not certain it has anything to do with the problem, my girlfriend was nervous about the older microwave and persuaded me to buy a new one.