OK, I was recently remodeling a bathroom and changed the light switch and power plug for a togle switch and gfci outlet. Well after turning the circuit back on at the electrical panel I noticed their was no power to the adjacent bedroom. No lights as well as no power to any of the 4 outlets. So I verified every wire was conected, nothing. Then I turned the power back off and switched everything back the way it was, nothing, still no power. So I broke out the handy multimeter and I saw something weird a white common wire was backfeeding 80v so I removed it and wired the rest to see if that gave me any power and nothing. I have left all the wires intact but am lost as to the cause of the problem. I took some picture's of the wires HERE the white with the yellow wire nut is the culprit. Please help. Thanks!
Oh yeah, you can reach me at tiznaki@gmail.com or post here.

 

Put your digital multimeter away and don't use it again for debugging an AC circuit. It is not reading 80 volts. It is reading a phantom voltage on the line.

You must use either an analog multimeter or a simple tester to see what is going on.

Your most likely culprit is an open neutral. You will be able to confirm this with a tester. Test for voltage betwen the incoming hot wire and the incoming neutral, and then between the incoming hot wire and a good ground. You will most likely see that the neutral is open.

If this is the case, you will then have to go find the open neutral. And of course, repair it.

 

Your multimeter is providing misleading information. Put it aside for the time being. We can discuss why it is misleading later, but I don't want to get sidetracked. For now, just forget that 80-volt reading.

In order to spot the problem and suggest a correction, we need more information. I can guess some of it from the excellent picture you provided. The white wire with the yellow wire nut--was it exactly like that before?

I can't quite count the wires in the box accurately from the picture. Exactly how many black wires, and how many white wires are in the box?

Do I see two wires under one screw? That's a big no-no. Do I see both 12-gauge and 14-gauge wires in the box? Is the breaker 15-amp or 20-amp?

 

Someone replied to one of my posts several months ago and pointed out a possible problem when testing for voltage using a digital multi meter. Apparently it is possible that you could be seing a "ghost" voltage.

I hate to state the obvious but if everything worked before and it does not work now than something has changed. You could have hooked something back up incorrectly or something came loose. Double check all the wiring connections, even the ones you did not disconnect. Maybe a wire in a wire nut came loose.

 

Let's see, there are 5 lines running into the box total, the new romex 14 gauge line is running to the whole house fan and there are 4 other older looking wires. 1 goes to the light in the bathroom and 1 I assume brings the power into the box so that leaves 2 unaccounted for. Yes there is both 12 and 14 gauge wire and yes I terminated 2 wire's under the flat square washer type clamp under the crew. Should I change that? Also there are 2 instances where multiple wires are clamped together with a copper sleve and a pigtail runs out of it. Should I change that? Also if I have an open nuetral can I just hook up my tone generator and check for continuity by trying to complete the circuit shoting the tone out? Or at least verify where this line works. To answer another question: No the white wire was not wirenutted when I started but since it had what I thought was foreign voltage I capped it off. Finnaly it is on a 20 amp circuit. Thanks for all the info guys. Hope this helps you help me.

p.s. If any of you need any pictures from different angles or closer up just ask it's all digital so it cost's me nothing but time.

 

The 14/2 going to the whole house fan violates several electrical codes. It can't be 14-gauge, and the whole house fan can't be powered from the bath receptacle circuit.

And the two wires under one screw is another code violation, and easily solved with a wire nut and pigtail. A copper sleeve connector is fine as long as it was applied with the proper tool (which isn't a pair of pliers).

Disconnect and separate all the wires from each other, and use a two-dollar neon circuit tester (not your multimeter) to figure out which cable is the power cable. You can't sort this out until you know which one that is.

 

I have a few questions, What gauge should the fan wire be? and where to? also the box is pretty tight as it is, especially with the gfci outlet, so it looks like i'll need to use more sleves. What tool is required? I have a set of klein crimpers but they are for crimping the little red, yellow, blue connectors. Would those work? So once I have everything taken apart what do I look for after I have isolated the main wire feeding the box?

 

All wiring on a circuit protected by a 20-amp breaker must be at least 12 gauge.

Install a larger box, install another box, install a junction box in the attic, ... Do something to reduce the crowding. Just make sure all splices end up in permanently accessible boxes. If it was me, I'd install a new circuit for your whole house fan.

Once you know which pair is the power feed, then figure out which pair runs to the light. Then connect all the black wires except the light black to the power cable black, and all the white wires to the power cable white.