GFCI Keeps Tripping

I have a 20 amp GFCI outlet in the kitchen, which is only used for the toaster oven that is always unplugged except when in actual use. Upstream from this outlet is another outlet (and the only one on this run) that is only used for the coffee maker which is left plugged in all the time. Lately, I have had to re-set the GFCI outlet before the coffee maker will work. What could be causing this -- something in the wiring or the coffee maker?

Thanks

 

You mention that the coffeemaker is "upstream" from the GFCI, and yet the GFCI must be reset before the coffeemaker will work. This is illogical, so I'm going to assume that the coffeemaker is really "downstream" from the GFCI.

It indicates either (1) a bad GFCI, or (2) a ground fault. For about $8, you can try replacing the GFCI to rule out (1).

Ground faults can be caused by a number of conditions. In a kitchen, it is sometimes just moisture in one of the boxes. It could also be a faulty appliance.

Experimentation is called for. Try the coffeemaker in a different circuit with GFCI (e.g., a bathroom), or a different receptacle on the same circuit. Try the toaster oven on a different GFCI circuit. Plug a clock or radio in the coffeemaker receptacle so that you will be alerted to exactly when the GFCI trips. Knowing what event happened that tripped it would be a very important clue. You should also consider all other loads on the circuit as possible problems.

 

Are you saying that each time you make coffee you have to reset the GFI and then the coffee maker performs its function normally and then sometime before the next coffee making event the receptacle trips again? Do you leave the coffee pot on for a long period after brewing? As John said, next time you make coffee, plug a radio in as well and determine when the receptacle trips. It sounds like you probably have a bad GFI or possibly a bad / loose / corroded connection somewhere. It could be that the electronics in the GFI fail after a period of time from heating up due to the current draw of the coffee maker, but it takes longer than the normal brewing cycle. It could be a loose connection on the receptacle that the coffee pot is plugged into. Arcing anywhere in the circuit beyond the GFI can sometimes produce nuisance tripping. It could be a loose connection on the GFI receptacle that is creating heat and tripping the receptacle. Since you're circuit is so small (number of devices) you should turn the power off and inspect your devices for loose terminals or discoloration from a hot spot. If you truly only have 2 receptacles on the circuit you should have (2) 12-2 cables entering the GFI box and (1) 12-2 cable entering the box at the coffee maker. Any other configuration of wiring means you will have another receptacle (at least) on the circuit that could be the spot of trouble as well. One other thought - I'm not sure about the circuitry of a coffee maker, but it could be that the brewing cycle works fine and the "hotplate" circuit has a slight fault that trips the GFI. That would assume that the heating cycle is independent and is energized after the brewing cycle is completed. As John said, try plugging the coffee maker into another GFI (bathroom?) and see if it trips. If so, get a new coffee maker.

 

Thanks for your suggestions. The coffee maker does not have a hot plate because the pot is one of those thermal ones. And, it doesn't happen every morning. I will pull both outlets for inspection over the weekend. These are the only 2 outlets on this particular circuit, and I will try moving the coffee pot to another outlet to see what happens.

 

Does it only happen when you use the coffee pot? Does it trip when you plug it in or during use of the coffee pot? It sounds like the coffee pot may be defective. Test it in a different gfci outlet. There should be one in your bathroom.

 

I switched the coffee pot last night to a different outlet and plugged in a nightlight in the suspicious outlet to see what would happen. The GFCI did not trip during the night. In answer to the previous reply, the GFCI trips at some point during the night before I start brewing coffee. Will take a look at the outlets over the weekend.
Thanks again.

 

Is it possible that the coffemaker trips the GFCI when it turns off?

 

If you switched the coffee maker to a different outlet that is not GFI protected there is a good chance that you won't have a problem. However, you need to determine if the problem is in the coffee pot or is in part of your circuitry (including the GFI receptacle). The best way to do this is to try the coffee maker in a different GFI receptacle (preferrably on a different circuit). If you trip that GFI you need to get a new coffee maker because there is some sort of fault with your coffee maker. If you have no problem, then check the circuitry in the kitchen (which means possibly replacing the GFI). If you do change the GFI and still have the problem, inspect the entire circuit as I suggested above.