GFCI outlet won't come on

Question

I have a couple recently installed (By a professional licensed electrician) GFCI outlets outside a barn, both on their own circuit.

Both have water trough heaters plugged into them - 1500 watts each.

These have been running for about 2 months now without any problems until last night; we got a hard freeze (around 10°F) and everything had frost on it this morning (if that makes any difference) and now one of the GFCI outlets isn't working.

I looked at the circuit breaker and the circuit the outlet is on was tripped, so I reset the breaker and the outlet still won't come on.

I've tried unsuccessfully to push the reset button as well as the test button, but neither click (I believe the test button should click when it's pushed far enough and it shuts the circuit off).

So at this point, I'm wondering what could be the issue and what are the possible issues and the best ways to track down the problem.

1. Could the circuit breaker be dead? If so, is there a way for me to test it?
2. Could the GFCI outlet be dead? Or maybe there's some frost frozen in there that I might have to thaw out to see if that does the trick?

Answer 1

Not an uncommon problem. I have had a lot of problems with GFI's the last few years myself. There are a few likely causes:

1. A fault still exists and will not allow the GFI to reset.
2. The GFI tripped due to an overload and the differential circuit was damaged, thus the outlet is now toast. This seems to be a common complaint with standard 15 amp GFIC's. they don't take current spikes well. In your case 1500 watts on 120VAC is pulling around 12.5 amps, which is getting close to max capacity. Sometimes the initial current draw is much higher as the resistive load needs to heat up a bit before it reaches its operating impedance. A "cold" load can offer a much lower impedence and cause a short duration, but large spike of current to flow at turn on. Very common on motor loads, but not uncommon with filament heating or lighting.
3. Sometimes if you turn off the power to this GFI at the breaker, then push the test and reset buttons, then turn the power back on again, the GFI will default to the tripped condition, but will reset.
4. Disconnect any wires connected to the "Load" side of the GFI. Unplug all loads from the GFI itself, and give it a try.
5. If none of the above items work for you, you will probably need to replace the GFI. Find one with a 20 amp rating instead of 15 amps, assuming that 15 amp is what you have now.