2 Issues - tripping breaker, broken neutral

11 years ago

I have 2 separate issues that I'm looking for some opinions on. Each is on a separate circuit.

1) GFCI circuit. Outlets in main floor bathroom, entire upstairs bathroom, single outside outlet.

A while back I was getting random trips on this circuit and traced the issue to water getting into the outside outlet. Removed the outlet and capped the wires, sealed it up and no more issue. I'm trying to now replace the outlet and install a weather proof as I'd like to plug in the block heater on my truck. When I replaced the outlet and plugged in the heater (it should be somewhere between 650 and 1000 watts), it trips the breaker. I can plug this into other circuits without issue. I tried removing the outlet and plugging the cord into an inside outlet on the GFCI circuit and it still trips. Is the breaker going bad? It's 20A and there wasn't anything else running on the circuit at the time. The only other thing I can think of would be a wiring fault, but the fault tester I have shows no issue and I can use the lights and outlets without issue otherwise.

2) I have another outside outlet on a different circuit that is also having issue. It gets current on the hot/black wire, but the neutral seems to be disconnected.

This outlet is wired into a non-GFCI circuit. 2 inside outlets, 1 single box outside light, 1 pair of outside lights, a ceiling fan on a 3-way switch, and the outside outlet in question. Everything else on the circuit is running correctly. The outlet SEEMS to be wired to a 3 gang switch box. There are 2 red/black/white/ground cables and 2 black/white/ground cables in the box. By what I can tell, the 1st r/b/w/g cable is the primary hot, and neutral, and also runs to the 2 box outside light. The 2nd r/b/w/g cable runs to the ceiling fan 3/way. One of the b/w/g cables goes to the single outside light, and the other goes to I don't know. I would assume the outside outlet uses this line, but that outlet only get current on the hot if the 3-way ceiling fan is connected. What should I be looking for here?

Comments (6)

Ron Natalie
11 years ago
1. The other possibility is that the heater has a ground fault in it.

2. What are you doing to detect that the neutral is disconnected? If the neutral is indeed open, you're going to have to start there and work back to each possible junction to find where it is open.
All outside receptacles really ought to be GFCI protected.
Alexsha
Original Author
11 years ago
1) What would be the best way to test for a ground fault in the heater? As I mentioned, it does not cause any issue with a non-GFCI breaker.

2) With the power on, I run a voltmeter across the black and white and get 0 voltage. I used a touchless voltage probe to check the hot wire for current.

The big issue with this outlet is that I don't know where the cable even runs to. Is there some kind of tone/signal tester I can hook to the neutral so I can check in the switch box to see if the tone/signal is coming across?

I certainly agree on GFCI protection for the outside outlets. I'm not sure why all the outside lights and outlets aren't on their own circuits.
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Alexsha
Original Author
11 years ago
Could corrosion on the prongs of the block heater cord cause the ground fault?

If I installed a GFCI outlet on the outside and plugged the heater into that and it tripped, that would indicate the extension cord, heater cord, or heater element itself is the issue, correct?

This post was edited by Alexsha on Mon, Jan 7, 13 at 13:49
Ron Natalie
11 years ago
I'd suspect some gunk inside that is bridging ground and neutral (since the heater appears to work on a non protected circuit.

Those non-contact testers give a lot of false positive. I would almost guess that there's not any voltage on the HOT line and most likely, it's not connected to anything.

If you can find a known good ground somewhere, measure between HOT and that ground (and then neutral and that ground).
Alexsha
Original Author
11 years ago
I checked a few things last night. The block heater runs at around 6.5 amps, so it's not a big load. I cleaned off the contacts on the plug, but I didn't get a chance to plug it into one of the indoor outlets on the GFCI circuit. Going to try that tonight.

The outlet on the side of the house is NOT getting any current. I guess the wire is close to the hot on the ceiling fan and picking up something. I think it might actually be on the same GFCI circuit as the front and bathrooms. I guess I'll have to check all the switches and outlets on that circuit to see if I can find some disconnected wires.
brickeyee
11 years ago
Sounds like an older installation that allowed a single GFCI receptacle to serve multiple bathrooms and even outdoor receptacle s all at that same time.

At the time GFCI devices cost a lot more than they do know.

A good up grade would be to use separate GFCI receptacles in each location, all fed from the line side (so they are not feeding each other).

It should only take simple wire changes in each device box.

Open heater elements are notorious for developing ground faults.

The bare heating element is electrically hot and debris gradually creates enough of a carbon track from the element to ground to trip a GFCI.

Just noticed this is a block heater.

If it uses the typical heater rod there is likely a crack in the rod covering.
Even a crack so small you cannot easily see it will allow enough liquid to enter and contact the actual heating wire in the rod.

This post was edited by brickeyee on Wed, Jan 9, 13 at 13:39