circuit on two breakers?

I was replacing an ivory GFI with a white one in one of our two bathrooms (#1). There were two sets of wires (blk/wht/grnd), merged, to LINE side of the GFI, which I assumed were the supply line in and a continuation line out to the GFI outlet in the other bathroom.

Curiously, both sets of wires were hot. I had to shut off two 15 amp breakers, one for each set of wires.

Assuming this was a wiring error, I closed off one of the sets with wire nuts, leaving it unconnected, and wired the new GFI with the remaining set. It works fine.

Now the GFI in bathroom #2 now will not power anything. BUt when the light is on in bathroom #2, both the black wire and the white wire of the outlet show hot to ground; when the light is off, the outlet is dead.

I can understand that the two outlets were powered off the same circuit, and that I disconnected the one in bathroom #2. But I don't understand why the second one isn't dead all the time. Is this a normal situation or are two circuits somehow cross-connected?

 

I suspect your testing procedure was flawed, and that both sets of wires were not in fact hot.

Please tell us exactly what kind of test device you used. Was it by any chance a digital multimeter?

Then tell us exactly how you conducted the test. I assume that you took all the wires off the receptacle and separated them all. Then you measured for AC voltage between each pair of black and white wires. Is this true? If so, and if my first guess was also true, then what voltage readings did you get on each pair?

 

I used an inexpensive tester with a probe on the end, and a wire coming out of the other end with another probe on the end of the wire. The tester has neon bulbs on it to indicate 120 and 240 volts. The 120 volt bulb went on.

I did not disconnect the wires from the outlet. I simply put the probes into the outlet, between the ground hole and one or the other of the slots, where a plug would normally go.

I don't understand why the outlet in bathroom #2--which was presumably ganged to the outlet in bathroom #1 and which I would seem to have disconnected--shows juice when the light in bathroom #2 is turned on. It shows no juice when when the bathroom light is turned off.

 

Okay, it's not what I thought at first.

So if you just tested from the ground hole to the slots, I'm not sure how you concluded that both sets of wires were hot. Since these sets of wires were connected to each other, one set would always be how whenever the other one was.

There's a lot here that is still confusing. We need more testing to clear things up.

Turn off both breakers (I'll call them #A and #B). Take out the receptacle that you just put in. Disconnect all wires from it. Separate all the wires in the box so that none are touching each other. With both breakers still off, test each of the two black/white pairs (using your tester probes on the black and white of one pair, and then the black and white of the other pair). Does the tester light up on neither pair, pair #1 only, pair #2 only, or both pairs? Turn on breaker #A. Repeat the tests on both pairs of wires. Turn off breaker #A, and turn on breaker #B. Repeat the tests on both pairs of wires. Turn on both breaker #A and breaker #B. Repeat the tests.

Post back with the results of all eight tests:[list=1][*]#A off, #B off, pair #1.[*]#A off, #B off, pair #2.[*]#A on, #B off, pair #1.[*]#A on, #B off, pair #2.[*]#A off, #B on, pair #1.[*]#A off, #B on, pair #2.[*]#A on, #B on, pair #1.[*]#A on, #B on, pair #2.[/list=1]

 

Thanks. I will do the tests if need be, but it seems to be me that the outlet in bathroom #1 is out of the picture. It works fine. I only included it in my description to show how the problem in bathroom #2 arose (by apparently disconnecting it from its presumed power source).

The question I have is why, when the outlet in bathroom #2 would appear to have been disconnected from the circuit, does it show hot when the light in bathroom #2 is on and not hot when the light in bathroom#2 is off? By hot I don't mean the outlet works--it doesn't--I mean that the tester shows 120 v from either the white or the black to ground.

Thanks for your patience.

 

I am going to geuss that someone tried to install an outlet into a switch loop in bathroom #2. When that didn't work they tapped into bathroom #1. and caused a cross connect with the light circuit.
Open the outlet in bathroom #2 and disconnect the wires from it that go to the light or the switch. Connect only the wires that go to bathroom #1. Connect the wires up at bathroom #1 again.

 

Thank you, I will try that.