I’ve got a feeling this one’s going to embarass me, but I’m hoping that I’ve overlooked something simple.
I installed a new 20 amp circuit feeding a 20 amp GFI and an additional 20 amp recepticle. When I push the GFI’s reset button, I see a flash and it trips the breaker. If I unhook the additional recepticle, I can reset the GFI and use it for power. I tried a second GFI, with the same results.
The power feed is connected to the Line terminals and the additional recepticle to the Load terminals. I tested the additional recepticle and wiring with a VOM, with no shorts or opens.
What am I missing?
Replies
I'm not an electrician. I'm not an electrician.
I would check the wires for short going from GFI to next recep.
And is it possible that your neutral wire is on two different circuits?? I believe this would cause problems..
Good luck.
Bob
Just to be clear, because alot of time the terms are missused.
You have circuit breaker feeding a GFCI/receptacle and that feeds via the load termin another receptacle.
" When I push the GFI's reset button, I see a flash and it trips the breaker. "
You are talking about the Circuit Breaker tripping, right?
Off the top of my head the only thing that I can see is that something is shorting out when the connects are made and pushed into the box.
Look at the wires going to the receptacle very closing for any cuts in insulation, etc.
You are correct. I see a small flash in the GFI plug and the circuit breaker in the panel trips. All of my testing is being done with the recepticles and wires out of the boxes, so I'm not moving anything. The problem remains that the testing shows no shorts or opens in the wiring and second (load) recepticle, yet it trips the GFI and circuit breaker.
The only thing that I can think of is that there is some insulation that is breaking down at 120 volt.Possibly a bad spot in the cable.But try removing the receptacle at the far end, with leave the cable connected to the GFCI.It would be strange for it to be in the receptacle, but worth a try.
Do you have cable(romex) or raceway(pipe, flex) between the two devices? How old is the wiring?
You must have a short in the wiring between the devices. Perhaps a staple driven to deep, a nail from a door frame, a drywall screw or nail, or possibly a cut cable.
Try a continuity test between all combinations of the wires between the two devices. Also test continuity between each wire and a known ground.
If you haven't drawn blood today, you haven't done anything.
The problem is there whether I have a receptacle at the end or not. I used a VOM to test every combination. Infinity resistance between the hot, neutral and ground. Zero ohms between every pair when clipped together. My conclusion was no shorts or opens. The wire is brand new 12/2 with ground romex. It runs behind three 16' sections of new beaded kneewalls that took three days to install. Major cost to reopen the walls and no other way to run a new wire.
When you say you installed a new 20 amp circuit, does this mean new line from the panel? Or is this a piggy back off of a bedroom circuit? Maybe an AFCI breaker?
You might have a faulted cable. Also wires with damaged insulation often short, on the device screws, ground wires or box if it is metal, when stuffed into a box. When you pull them out the short disappears. Also any neutral to ground connection downstream of the GFI will trip it. The only neutral to ground connection should be in the main panel.
If the box has a clamping device loosen it and pull a bit of the cable into the box. Inspect the place where the clamp was and the wires where you stripped the jacket away very closely with a bright light. Use your nose also. An arc will produce a distinctive smell I commonly find faults by following my nose.
Those clamps are fine thread screws which can put a lot of pressure on the cable with even fairly moderate screwdriver torque. I have seen, created, a few shorts that way.
If you use a NM stripper that cuts the jacket all around when clamped on the cable be doubly sure to check the area. Especially when new these tools can easily cut too deeply and nick the insulation on the wires. This makes them even more susceptible to an over tightened clamp. This sort of short, clamped or not, can often disappear when the wires are moved.
One trick is to temporarily bypass the GFI. Hook the circuit up to the breaker and see if, over perhaps ten minutes the breaker trips.
This can make the fault location clearer. It will be near where the firemen are chopping the wood out and using the hose. A joke but it points out that electrical work is not without some risk.
You say all the conductors in the cables read clear. I suspect your reading using the ohm range on your meter. A short that bleeds more than 5ma at 120v may not read at all with the 9v the meter uses. Hook each conductor in turn to a breaker and read the other conductors. You might get a ghost voltage, rarer on such a short circuit, but ghost voltages tend to vary while a real fault will be steady. A Wiggy or neon tester will normally give a steady reading.
Also you can try making a fault show up by rigging a load. I use a hair drier that pulls a demanding 12A with the GFI out of the circuit. Any short or loose connection will heat up and reveal its location. Just follow the firemen.
This is a brand new circuit back to the panel. The box is plastic and the problem is there with and without the load recepticle. All construction, except the finish beadboard, was done prior to wiring and the beadboard is fastened well away from the wires. Yes, I used a battery powered VOM to check the wires before finishing. I'll try some more testing, hopefully without involving the local FD. Thanks.
I'm pretty sure you have something miswired, but I can't say what. Often this kind of problem results when you have some conceptual hangup (eg, confusing the meaning of "load" and "line", visualizing a circuit wrong and actually wiring a short, etc). It happens even to the pros on occasion.
How about this: remove BOTH receptacles. In the first box, wire nut the blacks together, the whites, and the grounds. just let all the wires stick out of the two boxes, chase children and pets out of room, energize. If the breaker trips, you know the wiring is shorted somewhere, and that it has nothing to do with the GFCI and/or other receptacle. if it doesn't trip, you can breath a sigh or relief that you don't have a problem behind the walls.
I agree that you may have something very simple miswired. When I was a apprentice I accompanied our service guy to add an outlet for a TV. Easy... up the wall from another so the cord didn't run down the wall from the bracket hung set.
Anyway, we had to go back the next day because it didn't work. After quite awhile of being confused as to the cause, I noticed that the very experienced electrician had connected both the hot and the neutral to the same side of the receptacle creating a dead short.
Check again... the black wires on the brass screws and the white wires on the silver screws, bare wire on the green screw and it isn't touching anything else.If you haven't drawn blood today, you haven't done anything.
Yep, done all of that. Actually, the GFI recepticle makes it seemingly easy by itentifying the line and load sides and the hot and neutral sides.
I removed the GFI tonight, replaced it with a regular recepticle and the circuit worked fine. I'm thinking my next step is to try a third GFI recepticle or a GFI circuit breaker.
OK, installed a GFI circuit breaker in the panel and everything is fine. Should I call it quits or try a third GFI recepticle?
Go for broke -- change two or three things at once.
I'd try a third GFI......Mexico needs the money....sorry"
Got the distributor to break open a new case of GFI's. Third one was the charm. Go figure I'd get two defectives. Thanks, everyone.
..........whodda thunk"