gfci cb trips

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bill@usps06492

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I've installed a 2-pole gfci CB 30a 240v in a panel. With no load, and no wires attached to this circuit breaker it will trip as if it has an overload. The original gfi breaker was doing the same thing and so I replaced it thinking it was faulty. Now I'm scratching my head. The service I'm working on is a 3phase 120/240v with a 208 high leg. I checked for any volts between neutral and ground, my meter showed 0vac. I've moved it off the high legs, it still trips. There isn't a ground wire from builing steel or the water main to the panel, it's a 4 wire main lug, its an older service, but there is a ground bar in the panel. There is no grounding wire run wire the 4 wire feeders. I assume it is all bonded at the service disconnect. On a 240v gfci what do you do with the white pig tail? The manufacturer(GE THQB) states not to attach it to the neutral if there is no neutral used, but its vauge on what to do with the pig tail. There isn't a neutral load, it is for a 1ph 240v stationary wet saw used to cut concrete blocks, but if I don't attach the pig tail to the ground or neutral bar, when I hit the test button on the gfci, it will not trip. But even with the pig tail not tied to the neutral or ground, the gfci will still trip as if it is sensing an overload. Any ideas ??? Bill
 
Dennis Alwon said:
Here is your problem you must connect the pigtail to the neutral bar in order for the DP GFCI breaker to function properly
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I agree for the GFCI function to work, but if you didn't connect the white pigtail wouldn't it work like a 2-pole breaker?
 
You definitely need to land the white pigtail whether you are using it for a multiwire circuit or not. As far as the cb tripping without a load even connected that's strange. The gfi only monitors downstream n-h and n-g current. Unless the chip inside senses some sort of grounding problem in the system??? I know a neon transformer with built in gfi protection will not work properly without a connected egc. I would call the manufacturer of the breaker and talk to someone in the engineering dept. Also try the breaker in another panel and see if it works. Keep us posted.
 
I believe that part of the problem with the gfci tripping is a lack of an EGC, and a floating 64 volts between the neutral & ground on one circuit. When I first started this job I found all the neutrals and the branch circuit egc's, all landed on the neurtral bar, the bar is isolated from the panel.
There wasn't an egc bar in the panel so I installed one, moved all the grounds to it. While running some emt for the lighting I received a shock between the conduit and an existing box. There was 64vac between the two. I traced the circuit back to a main pull box near the panel and found a disconnected ground wire on this circuit and the 64v between the neutral & ground. I tied the ground wire from this circuit into the other grounds that are all bonded to this pull box thinking this would remove the 64v potential and make it safe to work on the circuit. There is a #10 wire from this box landed on the egc bar in the panel.
There isn't a main egc from the panel to the water main, or an outside rod, and there isn't any building steel or rebar to grab. the feeders do enter the panel from RSC from under a concrete floor. The voltages on the mains are 240v A-B, B-C, A-C, A & B to G-120v, C-G 208v.
I'm thinking that this floating 64v is what trips the gfci, it must be sensing it. I installed the first gfci prior to me seperating the neutrals and grounds, and finding this 64v. Everything worked fine. I've tried putting the cb on the mains that have 120v to ground, it still trips. Thanks for the help. Bill
 
I believe that part of the problem with the gfci tripping is a lack of an EGC, and a floating 64 volts between the neutral & ground on one circuit. When I first started this job I found all the neutrals and the branch circuit egc's, all landed on the neurtral bar, the bar is isolated from the panel.
There wasn't an egc bar in the panel so I installed one, moved all the grounds to it. While running some emt for the lighting I received a shock between the conduit and an existing box. There was 64vac between the two. I traced the circuit back to a main pull box near the panel and found a disconnected ground wire on this circuit and the 64v between the neutral & ground. I tied the ground wire from this circuit into the other grounds that are all bonded to this pull box thinking this would remove the 64v potential and make it safe to work on the circuit. There is a #10 wire from this box landed on the egc bar in the panel.
There isn't a main egc from the panel to the water main, or an outside rod, and there isn't any building steel or rebar to grab. the feeders do enter the panel from RSC from under a concrete floor. The voltages on the mains are 240v A-B, B-C, A-C, A & B to G-120v, C-G 208v.
I'm thinking that this floating 64v is what trips the gfci, it must be sensing it. I installed the first gfci prior to me seperating the neutrals and grounds, and finding this 64v. Everything worked fine. I've tried putting the cb on the mains that have 120v to ground, it still trips. Thanks for the help. Bill
 
I missed any mention about your neutral being bonded to equipemt ground (I think you indicate this is a service panel). From your voltage reading, it sounds like it may not be.

I'm a bit concerned in your statement that you "moved it off the high leg".
Were it ever on the high leg, it may be too late.If it trips with no wires attached other than the pigtail, I woud think "bad breaker"
 
bill@usps06492 said:
I believe that part of the problem with the gfci tripping is a lack of an EGC, and a floating 64 volts between the neutral & ground on one circuit.
Click to expand...
A GFCI does not need an egc to function.

I am also confused by your post. If this is not a main panel then it does not get an EGC ( or did you mean GEC) to a rod or water pipe.

Is the neutral from the GFCI tied to the neutral bar?

If the breaker trips with no load wires attached then you have a problem with the breaker as stated above.
 
augie47 said:
I missed any mention about your neutral being bonded to equipemt ground (I think you indicate this is a service panel). From your voltage reading, it sounds like it may not be.

I'm a bit concerned in your statement that you "moved it off the high leg".
Were it ever on the high leg, it may be too late.If it trips with no wires attached other than the pigtail, I woud think "bad breaker"
Click to expand...
The original post says it is for a piece of 240v equipment. I don't see the problem with it being on the high leg...am I missing something Augie?
 
HotConductor said:
The original post says it is for a piece of 240v equipment. I don't see the problem with it being on the high leg...am I missing something Augie?
Click to expand...

I am not sure. Thats why I said "maybe". I'n not familiar with the internals of a GFCI, but the 220 ones I have seen are slash tratwed 240/120 which makes them a violaton on the high-leg. The fact that they have electronics and are connected to a neutral makes me suspect of them on high-leg but it is not a confirmed concern.
 
You probably plugged that breaker into the high leg and fried its internal components. It's now lost its "smoke" and fodder for the landfill. :mad:

Try another new one, and this time, make sure you are on the 2 normal phases .... :wink:
 
Thanks for all the advice. But to clear up a couple of things. 1) I made sure that this gfci cb was not on the high leg the first time I installed it, because I thought that it would be damaged by the high leg voltage. 2) this is a main lug panel, it's an older service, early 70's vintage, plug in type GE cb, and there isn't an equipment grounding conductor run with the 3 hots and neutral that feed this panel. Also there isn't any grounding conductor run to the water main, or outside to any rods from this panel. Bill
 
bill@usps06492 said:
Thanks for all the advice. But to clear up a couple of things. 1) I made sure that this gfci cb was not on the high leg the first time I installed it, because I thought that it would be damaged by the high leg voltage. 2) this is a main lug panel, it's an older service, early 70's vintage, plug in type GE cb, and there isn't an equipment grounding conductor run with the 3 hots and neutral that feed this panel. Also there isn't any grounding conductor run to the water main, or outside to any rods from this panel. Bill
Click to expand...

Thanks. There is still some doubt in my mind (probably my fault) as this being a "service panel". Is there some type overcurrent proetction ahead of it ? If the the grounding electrode conenctions (water/rod etc) would be made from the 1st overcurrent (service) disconnect. The 64v reading stills leads me to beleiev there is no neutral-ground connection.
In that panel is fed without and equipmet ground (assuming there is no conduit ground) and it being a 1970 install, I would think there might be a missing bond connection. At some point in the system there must not be a suffiecient neutral-equipmet grounding bond.
 
090302-1643 EST

bill@usps06492:

The pigtail should not be connected to anything in your application. If you had 120 V loads on this breaker, then the neutral to those loads would be connected to the pigtail instead of to the neutral.

With the pigtail insulated, wrap some tape around it, and no wires to the hot output terminals of the breaker, then the breaker should not trip. If it trips, then take it to your shop work bench. Make sure you are working on an insulated surface, a clean wood top bench.

Set the breaker, this may require input power. Connect 240 V to the two hot input terminals. Probably use clip leads. The breaker should not trip. If it does, then my guess is that it is a defective breaker.

If it does not trip, then use a 15,000 ohm resistor from one hot output terminal to ground (EGC). This should cause it to trip.

If 15,000 ohm resistor does not cause a trip, then try a 25 or 50 W bulb in place of the 15,000 ohm resistor. If this does not create a trip, then the breaker is definitely bad. Or we need more information on the details of how this breaker works.

You should probably use a 1 W 15,000 resistor. Just a momentary touch, at most several seconds, should cause a trip. 120 V across 15,000 is slightly under 1 W.

.
 
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