Is there a way to test if a GFCI breaker is bad

[cank]

Back in February I bought a Midwest Spa panel from ebay and didn't get it hooked up until this summer.

Well, I could not engage that breaker at all so I contacted the seller to get a replacement.

In the mean time I have been using a regular breaker to brew with.

It took until yesterday to finally get the other breaker that he had lying around.

This one didn't work either.
I used this diagram.
I disconnected the load.
I checked all of the voltages.
Made sure there was no continuity between load and neutral.
I even tried to wire it this way to see if that would work.

A few other things I noticed. The first break would just not engage while the second threw my main panel breaker and had some sparks on that load side that showed continuity with the neutral.

Is there anything else I should check on my wiring?

But my main question is:
Is there a way to test a GFCI breaker?

The new breaker he sent has continuity between one of the load leads (On the same pole as the neutral pigtail) and the neutral lug.

In this diagram it would be between the Red and Yellow Line going from the breaker.

 

[ajdelange]

Clearly continuity between neutral and one of the phases represents a phase to neutral fault and the breaker will trip on overcurrent as soon as the circuit is energized.

GFCI's are tested by introducing a leakage path (large resistor but small enough to pass a bit more than 6 ma) between one of the phases and earth.

 

[The_Glue]

The GFCI does not care if there is continuity between phase and neutral.
It compares the current flowing in from the phases to the current flowing away to the neutral. If they are different by 50ma or whatever is stated in the spec it trips. This difference happens when some of your amps from the phases get wasted to the protecting earth.
"Continuity" between phase and neutral can be happen if for example the resistance of your heating element is lower than the minimum resistance set in your multimeter for continuity. For example a 220V 2000W heater have a resistance around 22ohms while my multimeter beeps everytime below 50 ohms with a continuity test.

The GFCI trips when you "waste" some of the current flowing in from the phases to the protecting earth which is not the same as neutral! So you might have some continuity (can be as high as ~4000ohm on 220V) somewhere between the phases and the protecting earth.

 

[cank]

When I saw there was continuity, I took the breaker out and even when disconnected it had continuity.

 

[ajdelange]

The GFCI does not care if there is continuity between phase and neutral.

No it doesn't and that's why I said it will trip on overcurrent. Continuity implies very low impedance i.e. a short. As confirmed in #4 this breaker is shorted i.e. continuity between pole and neutral with everything else disconnected.

 

[The_Glue]

When I saw there was continuity, I took the breaker out and even when disconnected it had continuity.

Like i said that is normal (to seemingly have contiuity between neutral and phases) if your loads are big enough. For example a few heating elements can result in lower than 10-20ohms resistance between phase and neutral which the multimeter detects as continuity.

I think you should disconnect all loads (like heating elements) and measure the resistance between the phases and protecting earth.

Btw i have never seen a GFCI breaker without a test button in my country.

 

[The_Glue]

No it doesn't and that's why I said it will trip on overcurrent. Continuity implies very low impedance i.e. a short. As confirmed in #3 this breaker is shorted i.e. continuity between pole and neutral with everything else disconnected.

By default a GFCI breaker is not an over current protecting device.

 

[The_Glue]

No it doesn't and that's why I said it will trip on overcurrent. Continuity implies very low impedance i.e. a short. As confirmed in #3 this breaker is shorted i.e. continuity between pole and neutral with everything else disconnected.

If he disconnected everything (like loads including) and measured a short then then you are right, the circuit have a short somewhere.

 

[ajdelange]

By default a GFCI breaker is not an over current protecting device.

It better be! Were it not one could not legally install it in a panel. The function of a breaker in a panel is to protect the wiring downstream of the panel from over heating caused by current beyond what the installed wire can handle.

Here's a picture of the insides of one. The over-current trip mechanism is clearly labeled. It would be quite possible to make a GFCI/ELCB only breaker but they don't. I have never seen one anyway.

This is, of course, distinct from GFCI/ELCB outlets which do not include over current protection.

 

[cank]

Like i said that is normal (to seemingly have contiuity between neutral and phases) if your loads are big enough. For example a few heating elements can result in lower than 10-20ohms resistance between phase and neutral which the multimeter detects as continuity.

I think you should disconnect all loads (like heating elements) and measure the resistance between the phases and protecting earth.

Btw i have never seen a GFCI breaker without a test button in my country.

They have test buttons but I can't even energize the breakers to push the button.

I not only disconnected all the loads, I took the breaker out of the panel and put it on my bench and the neutral and load showed continuity.

Let me ask you this; does the gfci care anything about the incoming lines? I.e. if there is currant leakage upstream of it, or is it just measuring current downstream? The service comes from an underground cable and I hope there is no damage to it.

 

[ajdelange]

Let me ask you this; does the gfci care anything about the incoming lines? I.e. if there is currant leakage upstream of it,

No.

..or is it just measuring current downstream?

Yes. It wants all the current that leaves the breaker to return through the breaker. If current returns through any other path (earth) it will trip. You can see how it works from the photo. The photo came from http://www.nema.org/Products/Documents/NEMA-GFCI-2012-Field-Representative-Presentation.pdf which may be of interest to those confused about how these things work and what they do.

The service comes from an underground cable and I hope there is no damage to it.

Even with one phase disconnected from the panel and shorted to earth the GFCI breaker would still protect the remaining phase. The fact that you see continuity between a load side pole and neutral plainly says that the breaker is defective.

 

[Hunky]

I bought one of these same units and it had a bad breaker, would trip with nothing connected to the out posts. Electrician confirmed that the breaker shouldn't care about upstream. Still awaiting replacement breaker.