How To Troubleshoot No Power

I've got a circuit in my basement that no longer is delivering power to all outlets. It's the light blue circuit on this diagram:



The panel is at the top of the image. I have power to the 3 outlets on the upper left, center left and lower left but not the two on the upper right and about in the center of the image. I've switched the breaker off until I figure it out.

I'm assuming the problem is in the junction box in the center left, but I don't know how to troubleshoot beyond a visual inspection. I have a multimeter, but have never used it to troubleshoot live house wiring. Hopefully, I'll open the box and the problem will be evident, but if not, how do I use my meter to troubleshoot this circuit?

Thanks,

 

Turn the circuit off. Open the junction box. Remove the wire nut from the black splice and look at the wires. See if they are all twisted together and are the same length. Do the same for the white wire.

It looks like there will be five black wires in one connection and five white whites in the other.
That's a big splice point.... and very easy for one wire to be out of the splice.

 

Have you read the sticky http://www.doityourself.com/forum/el...ther-info.html yet?

 

Thanks all.

No, I hadn't read that post yet, I'll take a look.

 

Also double check for a tripped GFI outlet.

 

OK, after 2.5 months, I'm finally getting back to this (the breaker has been off).

I opened up the main splice and found nothing obviously wrong. All the connections were still tight. At the 5-way splice, I had used 5-way, push in connectors similar to these:

[ATTACH=CONFIG]66980[/ATTACH]

Since I had power at the 3 outlets fed directly off the 5-way splice and not at the two chained off of it, I figured the problem must be in the wire from the 5 way to the first of those two outlets. So I pulled the first outlet, a GFCI. Again, no obvious problems, the wires are attached to the push-in terminals on the back of the GFCI and are tight.

I then started moving ceiling tiles to get a good look at as much of that wire as I could. Nothing obvious anywhere indicating a damaged wire, although I couldn't see 100% of the length.

I guess my next step, per the troubleshooting post, is to move the push-in connections on the back of the GFCI to the screw terminals. Any other thoughts?

 

The terminals on a GFI receptacle shouldn't be push ins. They should be the type where you loosen the screw and slide the wire in behind a plate. Those connection types are reliable.
Do you have power on those wires coming to the receptacle ?

You have power at the five way splice.
Three of the connections are confirmed good.
Did you check the ends of the cables where those other two arrive ?
It's extremely rare for cable to go bad and to have two cables bad is un-heard of.

 

You really need to use a tester. Its going to end up being a lot faster and more reliable than trying to guess where a bad connection is based on visual inspection.

With the breaker off open all the boxes and outlets so you can see each splice and connection and then turn the power back on and with a neon tester or a non contact tester check check where the power stops.

 

You should never use a non contact tester for serious testing. They are unreliable and just confuse the issue. A neon light tester is okay but better is an analog multimeter.

 

ray is the expert so I'd take his advice on the testing equipment.

Rereading the first post again, you don't need to open all of the outlets just the one on the top right. If the splice there has power the problem is the outlet itself. If it doesn't have power, you have a broken cable or a bad connection at the 5way.

 

I'd use a new connector at the 5-way just to eliminate it as a problem.

 

I finally got around to fixing this.

I checked voltage at both sides of the GFCI outlet. I had 120 at one pair of wires, essentially zero at the other end. Also, I discovered that the "test" button was not working (not sure why I hadn't tested it earlier).

Long story short, I replaced the GFCI and all is good.

 

That certainly was a long story. Thanks for letting us know the final outcome.

 

Yeah, it is probably the least used circuit in the house, except for the freezer. Unfinished part of the basement and the outlets at the back, least used outlets in the finished part.

We had run the freezer to another circuit and never missed that this one was off for nearly 6 months. We're now prepping the house for sale, so it needed to be completed.