GFCI Breaker Appears To Be Bad

72chevy4x4

I"m checking out a GFCI breaker installed for an outside (single) outlet. A plug-in line tester shows correct wiring at the outside duplex outlet, but whenever a load is placed on the circuit, the breaker trips. This is a new circuit and run of wire, leads me to believe the breaker is at fault. Do you get bad breakers from time to time which trip with low current (tested w/ a 60w load) instead of rated (15A in this case)?

Ideas are welcome :-) Its a GE breaker (no Siemens here!)

mdshunk

Did you terminate the circuit's neutral wire ON THE BREAKER? and connect the breaker pigtail to the neutral bar? Is this circuit 1/2 of a multiwire branch circuit? (black, red, white, ground) You can't protect 1/2 of a MWBC with a single pole GFCI breaker. Just some ideas to start off.

72chevy4x4

thanks for the ideas. Its a homerun circuit (no sharing of neutral). Hot wire on breaker and pigtail connected to the common neutral/ground bus. I did shorten the pigtail-will that effect the resistance of the internal circuitry?

mdshunk

BUT... is the white wire of that cable connected to the breaker or the neutral bar? This is the important part.

Sparky Joe

I think your load is faulty, because your little plug tester is also a load, and if that's not tripping it then it's whatever else you're plugging in.

mdshunk

Naw, those plug in testers will not trip an improperly connected GFCI breaker. That is well established, as the current of the neon lamps in them is below the trip current.

Sparky Joe

Well excuse me , Can you imagine i thought I was actually being intelligent.

What is the resistance on one of them anyway, mine looks like it has little christams tree bulbs in it, but I can't read the resistance even in the 10k setting. Which i guess would make sense seeing as the GFI won't see anything greater than 2.4k ohms

72chevy4x4

mdshunk figured it out-the load neutral was connected to the panel's neutral bar where as it should have been connected to the GFCI's load neutral connector. Thanks for point it out.

JackJohnson

FYI neon bulbs have no filament. They rely on the electricity to excite the gas and produce the glow. The resistance would be somwhere between extremely high, and infinite.

woodchuck2

X2, very common mistake. I have done it myself when in a hurry.

excellencee

It happens all the time. I have a journeyman that has done that for all arc-faults and GFCIs in a panel. It took a few houses to settle in for him. In his defense, he's one hell of a pipe bender.

Waco

I have learned to doubt existing circuits and installations before suspecting modern GFCI breakers are bad.

mdshunk

Agreed. It's been a long time since I've installed a GFCI of any sort that was bad right out of the box.

XanadooLTD

I like the Klein avatar.

Electric_Light

GFCI is a very high gain current transformer setup as a differential amplifier.

You know how you only put ONE wire when using a clamp meter, because when you put both wires in you get no reading.

In a GFCI, both conductors go through the clamp meter and magnetic field cancels out perfectly, so it actually does not know that current is flowing. It detects a ground fault when there is a leakage, because a very small amount of current that does not return by the neutral is detected as asymmetry. It doesn't even know how much current is flowing through the conductors. It just knows the amount of asymmetry.

So... the wiring incorrect and using the ground as the return path or there's an insulation failure in the wiring.

If the wiring is verified to be correct, you need to isolate the suspected section of wiring, open both ends and megger each conductor against eachother and ground.