GFCI issues

[jtl2]

Need some insight into an electrical issue. The GFCI circuit breaker tripped and I reset it and the 50 amp main breaker tripped. Flipped it off and reset the 50 amp. I've pulled the four outlets and checked them for shorts and there were none. I'm thinking it is internal to either the panel breaker or the one GFCI outlet that's in the GFI chain.

 

Any insight into more testing or next step?

 

John

[Darryl&Rita]

How are you testing for shorts?

[Kirk W]

Are you thinking of a GFI circuit breaker as the first picture, or a GFCI outlet as in the second one?

If the GFCI was a circuit breaker, what was it rated for, 15a, 20a, or.................. ? It seems very strange that the resulting would then cause a 50a outlet to open. When you say that you pulled all four outlets, are those all of what is on the GFCI protected circuit? What else, if anything was operating when your 50a main breaker tripped? Have you done any voltage checks and if so, where and what was the reading? Did you try resetting the main breaker while the outlets were removed?

[jtl2]

Are you thinking of a GFI circuit breaker as the first picture, or a GFCI outlet as in the second one?

w

If the GFCI was a circuit breaker, what was it rated for, 15a, 20a, or.................. ? It seems very strange that the resulting would then cause a 50a outlet to open. When you say that you pulled all four outlets, are those all of what is on the GFCI protected circuit? What else, if anything was operating when your 50a main breaker tripped? Have you done any voltage checks and if so, where and what was the reading? Did you try resetting the main breaker while the outlets were removed?

It's the breaker (15 amp) for the GFCI outlet. Everything else runs fine with the 15amp breaker off. Tracing wiring the neutral (white) wire and ground are showing a short going back to the breaker panel, don't think that is normal since they are two different busses in the panel. Will purchase a continuity meter today and check, I've been using a regular multimeter.

 

John

[jtl2]

I run a progressive EMS-PT50C at the hookup to the campground. Voltage runs 118 - 122 with no errors shown on the progressive protector.

[Dutch_12078]

If you're plugged in to shorepower, the neutral (white) and ground are connected (bonded) together at the park panel per the NEC. To trip the breaker, the hot leg (usually black) that comes from the breaker would have to be shorted to the neutral or ground.

 

Most multi-meters include a continuity function, usually in the resistance measurement section. Check yours before buying anything else.

[Kirk W]

So you say that the 15a circuit breaker that supplies your GFCI and other outlets trips, but when you reset it, that makes the 50a main breaker open, if I understand correctly. Did you try removing the GFCI from the circuit and then resetting both circuit breakers to see what happens, carefully leaving the wires to the GFCI open and nothing connected to them? It is possible that your GGCI has an internal failure.

 

As Dutch stated, it is normal for the ground(bare wire) and the white neutral to be connected together at the power pedestal but they should not be connected in the distribution panel of an RV. If you pull the plug from the power pedestal so that there is no 120V power available, then measure between the white and the bare ground wire there should be a very large resistance, like 5000 ohms or more. Your PT50C is basically telling you that the power from the pedestal is OK, but it has no ability to detect most problems internal to the RV. I believe that your Grand Design is a travel trailer so is it safe to assume that it has no built-in generator set?

 

You need to also measure between the black wire and each of the other two wires and all of those readings should be a very high number of ohms to indicate that there are no shorts. The GGCI monitors the amount of current passing through the various wires and if it detects more current through the black wire than it sees returning via the white wire it will then open up for safety and that difference can be tiny, so small as to be very difficult to measure with a typical meter. In most cases, the GFCI is early in the outlet circuit and is connected to then protect all of the other outlets so if there is a problem in any of them or anything plugged into them, the GFCI opens to protect the user. Outlets are normally connected so that the three leads all come from the power distribution panel to the first outlet, then that wires to the next outlet also connect to it and continue on to the next one in such a way that if you remove all leads from one outlet, all outlets farther down the circuit will be without power. While they do not have to be connected that way, typically the GFCI is connected to be able to interrupt the power to all outlets beyond it in the circuit. That way, only 1 GFCI can protect an entire circuit. Just so that you know, there are now circuit breakers that are GFCI and so protect everything in their circuits without the need for a GFCI outlet as is typically found in RVs and homes. That is what the picture is above.

 

It sounds as though there is either a major failure in your GFCI or there are wires that are shorted together in that circuit. Under normal circumstances, if there is a circuit problem being supplied by a GFCI outlet that will make the GFCI trip and open the circuit and you will not be able to get it to reset and supply power until the problem is corrected. If you could reset yours and it made the 50a breaker open, something is very wrong with the GFCI.

 

I don't see any need for a different meter. I use an ohm meter and have made my living with one for 40+ years. Continuity is just a feature added to most meters and is a function of the ohm meter. It is more a convenience than a need if you understand the use of a meter.

[jtl2]

Thanks for the info Kirk and Dutch. Yes it is a TT and no genset. I checked the other outlets downstream of the GFCI outlet and they are ok (resistance between the black wire and other two wires is high. Taking the white wire from the RV panel breaker off the GFCI outlet and using the resistance mode on the MM it shows a short between the ground wire and white wire (neutral) going back to the RV panel. The actual GFCI outlet never tripped, but initially it tripped the 15amp breaker and when I reset the 15 amp breaker the 50 amp breaker in the RV panel tripped. I'll try disconnecting the wires from the GFCI outlet and reset the 15 amp breaker and see what happens.

[Dutch_12078]

Even if there were a short between the ground wire and the neutral, John, it would not trip the breaker. As said, those two are normally tied together on the shore power end anyway. They're not supposed to be tied together within the RV, but that's for safety reasons. Tying them together in the RV panel opens up the possibility of a "hot chassis" situation if the shorepower outlet you're connected to is miswired with the neutral and hot leg reversed. Keeping the neutral and ground separate within the RV minimizes the risk of a situation where stepping out the door of your RV while holding onto a metal part and touching the ground, especially if it's damp, delivers a potentially deadly shock to your body.

 

With the breaker off, try reading the resistance from the black wire on the breaker to neutral with nothing plugged into any of the outlets. That should read as an open circuit. If it does not, try disconnecting the wires at the GFCI outlet from the breaker and check again. If it still reads as a short, the fault is in the wiring between the breaker and the GFCI. If it now reads open, reconnect the GFCI and disconnect the wires leading to the next outlet in the string, and check again. Open? Reconnect and move on to disconnect the next outlet and check. Rinse, repeat, until you locate the short, either in the wiring between outlets, or a faulty outlet. Oh, and I understand the most common cause of wiring shorts in RV's is misplaced screws or staples in walls that eventually work their way through the wire insulation. Sometimes it can take several years for a problem like that to show up. I once repaired a leaking water line that took 14 years to rub through on the pointy end of a screw that was either misplaced or too long for the location.

[Kirk W]

. Taking the white wire from the RV panel breaker off the GFCI outlet and using the resistance mode on the MM it shows a short between the ground wire and white wire (neutral) going back to the RV panel.

Was this reading taken with the plug for shore power disconnected? If the shore power plug was connected that would be normal even with the main 50A breaker open as it does not open the neutral or the ground leads. The neutral and ground are "bonded" or tied together in the park's power pedestal in most cases and always are back at the power distribution panel that supplies the pedestal. It is not proper for the two to be bonded in the RV distribution panel, as Dutch has stated. Basically the electric system is intended to treat an RV as one large appliance since like an appliance, it has a power plug connecting to an outlet.

[jtl2]

Tested some none GFCI outlets in the TT and the neutral and ground are bonded in those also. Now I'm thinking I have a problem with my power distribution center or converter.

 

John

[Darryl&Rita]

Stop looking for new problems. The Neutral and bonding conductor tied together is unrelated to the issues you are having.

[jtl2]

Stop looking for new problems. The Neutral and bonding conductor tied together is unrelated to the issues you are having.

Think that is normal for a house, don't think that is how RV's are set up.

 

http://beamalarm.com/Documents/120_vac_in_your_rv.html

[Darryl&Rita]

Think that is normal for a house, don't think that is how RV's are set up.

 

http://beamalarm.com/Documents/120_vac_in_your_rv.html

Correct. Normal for a house, incorrect for an RV. Unrelated to the issue you're trying to troubleshoot. Focus.

[jtl2]

Correct. Normal for a house, incorrect for an RV. Unrelated to the issue you're trying to troubleshoot. Focus.

Think the GFCI is a symptom of the bonded neutral and ground.

[Darryl&Rita]

Think the GFCI is a symptom of the bonded neutral and ground.

Still won't trip a breaker. The result of an on-board Neutral/ground tie would be a possible "hot skin" under certain conditions. Above, you were asked if the plug was disconnected from the pedestal while testing the Neutral/Ground connection. We're still waiting the answer.

[jtl2]

With black and white wires disconnected from the GFCI outlet the 15 amp breaker at the panel doesn't trip.

[jtl2]

No bonding with power cable disconnected from the pedestal.

[Dutch_12078]

With black and white wires disconnected from the GFCI outlet the 15 amp breaker at the panel doesn't trip.

 

Reconnect the wires from the breaker to the GFCI, and disconnect the wires from the load side of the GFCI that feed the other outlets in the string. Does the breaker trip now?

[jtl2]

Went ahead and bought a new GFCI outlet. Hooked it up with just power and it works. Will hook up loads next.

[jtl2]

Well it wasn't the GFCI outlet. There are two load wires off the GFCI outlet, one goes to the other side of the kitchen island and the other wire goes to the front of the TT for the outdoor plug and then daisy chains back to the bathroom. The kitchen island works both the GFCI outlet and the load on the other side of the kitchen island. The front outlet and bath outlet check out with a continuity meter, but when hooked up to the load the breaker trips. Took them out of the circuit for now.

 

Thanks to everyone for their help and assistance.

 

John

[Kirk W]

The front outlet and bath outlet check out with a continuity meter, but when hooked up to the load the breaker trips. Took them out of the circuit for now.

I would look first at that outside outlet. They tend to be subjected to weather where the inside isn't. Very often the cover on an outside outlet doesn't seal well and allows moisture into the outlet or the internal wiring. If this were mine, I would open up the outside and remove the outlet and then pull the leads out so that you can inspect them as far inside as they can be seen. If you see nothing amiss, pull them out and separate them well apart and leave them that way while you go back in and turn everything else on to see what it does then. I'd give pretty good odds that the breakers will not trip and everything will work with it that way. The catch is that you then need to figure out what is going on inside of your connections and outlet, but at least you will know where to look.

 

Good Luck! and keep us posted.