GFI Breaker

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  #1  
Old 06-30-03, 10:48 PM
guydude
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GFI Breaker

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Cutler Hammer CB Single pole 15 Amp GFI breaker. Installed per manufacture's instructions. White ground wire on breaker to neutral/grounding buss bar. Neutral circuit wire attached to neutral lug on breaker. Hot wire attached to load lug on breaker. Switched to on postion and breaker tripped immediately. I took the neutral wire off the breaker and attached it to the neutral/ground buss bar. Turn on the breaker and it tripped immediately again.

Per troubleshooting guide that came with breaker, possible reason was panel's neutral and grounding buss bar are the same buss(This is the situation with this panel). I did find that the circuit was wired in a way I've never seen though. The circuit is a 14-3 "romex" cable. One hot wire was connected to one 15 amp breaker and another hot wire was connected to another 15 amp breaker. Both circuits "shared" the neutral wire.

Trying to get one of the circuits on the GFI breaker because of some new wiring to an exterior application and didn't know for sure where the first "load" was to install just a GFI duplex. What are my options here? Try to install a separate grounding buss bar and isolate the neutral buss bar from the panel? Or am I missing something?
 
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Old 07-01-03, 07:47 AM
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The first way you hooked up the breaker (circuit neutral to the breaker) was correct. The second way (circuit neutral to the grounding bar) was wrong.

Having the neutrals and grounds on the same bus in the panel will not cause this problem. I have no idea why the troubleshooting guide would identify this as a possible cause.

Also, the multiwire (aka shared neutral) circuit that you found (the one with the 14/3) is (probably) okay and has nothing to do with your problem. We can talk about that later in another thread if you'd like. But let's fix your GFCI problem first, and not confuse this thread with two separate issues.

First, confirm that the hot wire you connected to this GFCI breaker does not share the neutral with another circuit like the other 14/3 circuit you mentioned. If it does, then that's your problem. If it doesn't, then the problem is most likely outside the panel.

You probably have a simple ground fault. Several things can cause a ground fault, and there's no easy way to find it without a lot of looking and experimenting. Most likely culprits are (1) moisture in a box, (2) wires touching in a box, (3) a bootleg ground, (4) the neutral is shared with another breaker (as mentioned above).

First, shut off the breaker and test every receptacle and light in and out of your house. Make a complete list of everything that is on this circuit. Then go disconnect the wiring from each receptacle and switch one at a time (very carefully recording how it was previously connected). Between each device removal, try to turn the breaker back on and see if it stays on. If it does, then the last thing you removed (or something downstream from it) is the culprit.

A lot of tedious work. Might as well get started.
 
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Old 07-01-03, 12:37 PM
guydude
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>>>Also, the multiwire (aka shared neutral) circuit that you found (the one with the 14/3) is (probably) okay and has nothing to do with your problem.

First, confirm that the hot wire you connected to this GFCI breaker does not share the neutral with another circuit like the other 14/3 circuit you mentioned. If it does, then that's your problem.<<<

Thanks for the reply. I am a bit confused though on the above quote. If I understand correctly, you're saying that the current 14-3 cable with the 2 hots and a shared neutral is ok but if there is a third or more hots sharing this neutral, then that's the problem?
 
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Old 07-01-03, 01:45 PM
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I misunderstood. Upon rereading your original post, I see that you did indeed connect one of the two hots from the 14/3 to your GFCI breaker. This is positively the source of your problem. You cannot successfully do this.

You need a 120/240 double-pole GFCI breaker. These are pretty expensive and hard to find in 15-amp sizes -- you probably cannot find one at Home Depot; you probably need to go to an electrical supply house. You may also need to rearrange the two circuits if the breakers are not one above the other.

There may be other possibilities, but I cannot tell without the bigger picture. Exactly what do these two breakers provide power for, and what are you trying to accomplish?
 
  #5  
Old 07-02-03, 12:35 AM
guydude
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Both breakers power interior lights and plugs. The 2 circuits are completely seperate circuits. A new patio cover was installed. Owner wanted to install ceiling fans and outdoor lighting fixtures on the new cover.

An existing exterior patio light and interior switch was the source for the power to these fans and lights on cover. A 14-3 "romex" cable was added to the line side of the switch. One hot wire was run directly to the ceiling fans. The other hot wire was connected to a dimmer switch and then out to the outdoor lighting fixtures.

Since this original circuit was not connected to any GFI breaker or plug and didn't want to try to track down the wiring to connect a GFI plug, the breaker was my first thought to install.

Seeing how this extended circuit is now run exteriorly, it has to be "protected" with a GFI circuit.

If I understand what you're saying now is, if I connect the other circuit that shares the neutral with the other one, on a GFI breaker, it will work?
 
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Old 07-02-03, 07:40 AM
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Thanks for the additional information. There are a lot of factors to consider.

First, only receptacles are required by code to have GFCI protection. Neither switches nor lighting nor fans need GFCI protection, even if outside. I'm not saying that GFCI protection for these things is a bad idea. I'm just saying it's not required.

Next, simply buying another GFCI breaker won't do it. If you are going to provide GFCI protection in the panel, you must buy a double-pole 240/120 GFCI breaker. These breakers can be pretty pricy, and as I said, hard to find in smaller sizes (they are easy to find in 50-amp sizes). These breakers have screws to connect both hot wires, and, here is the important part, a screw to connect the neutral wire to the breaker too.

A much, much cheaper solution is to do what you said you don't want to do. Trace the cable to the box where the 14/3 is split into two 14/2. If there is no such box (i.e., 14/3 is used everywhere), then you must split it yourself, or use the breaker solution described above. If it is split into two 14/2 cables, then you can replace a couple of interior receptacles with GFCI receptacles. Tracing the cable is not that hard and requires no special equipment. It's just a matter of disconnecting things and seeing what loses power.

Finally, electrically these two circuits are far from "completely separate circuits." In fact, technically, all of this is part of a single multiwire circuit. Do not make any changes in the panel to a multiwire circuit unless you fully understand how you can get away with two hots sharing the same neutral without burning your house down. It all relies on proper connections to ensure the the neutral conductor only carries the difference of the current on the hots, rather than the sum of the current. Mess this up and you have created a significant fire hazard.
 
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