Ask Me Help Desk - Neutral Break or loose wire?

Neutral Break or loose wire?

The last couple of days, the receptacle where our entertainment appliances are plugged in has been intermittently failing (power loss).

Tonight, I had a chance to investigate (but unfortunately killed the power and pulled the receptacle before checking voltages, thinking it was going to be a bad connection). When I put it back together and looked using the multitester, the hot wire is around 125v against ground (about normal for my house), the neutral reads about 44v against ground, and hot against neutral reads about 79v. When I check all of the other receptacles, switches, and lights that are on the same circuit, they appear to have normal levels (125v for hot/ground, ~0 for neutral/ground, ~125v for hot/neutral). The problem receptacle is at the end of the circuit, so it is possible I have a bad wire, but I am having a hard time finding the prior point in the circuit (old house with piecemeal wiring done over the years) to check the neutral connection there. The other receptacles, switches, and light connections nearby on the same circuit all appeared in good shape and with solid connections.

Any tips or tricks for narrowing it down? I can live with that receptacle terminated for now, but I'd like to sort this out and get it repaired (preferably without making holes in the drywall/plaster).

You could always plug a light into every outlet on that circuit, and start systematically disconnecting wires and flipping the breaker on, to determine which fixture feeds the problem outlet. I don't know beyond that, though.

I believe this problem is most likely caused by a loose wire connection at an outlet upstream from the one with the problem. due to the wire pushed into the back of the outlet, called Quik-Wire,Whiz-Wire, Stab-in-the-Back, etc.

These types of connections are notorious for being a problem and loosening, even thou you may see the wire is pushed in and all looks fine.

You may need to open each outlet and try pulling on each wire out of the back of the outlet to see if you can find one that is loose.

If this circuit is part of a 3 wire cable, then the problem is a open neutral, and the problem can be at any outlet or splice in any box.

As dmatos mentions, all you can do is start opening outlets and disconnnect wires, one at a time, to find the upstream device that is feeding the problem outlet. This device may be fed by a junction box in the basement or attic instead of another device.

Before giving up last night, I pulled all the receptacles, switches and lamps on the same side of the room as the problem receptacle, and didn't find any problems (checked receptacle connections and pigtails), but I could have missed something. Tonight after the kids are safely in bed, I will systematically do the whole circuit. So far one thing that scares me a bit is the romex coming into the problem outlet has black sheathing, but all of the outlets, fixture boxes, and switches I've pulled have had white sheathing. I know it's all one circuit based on continuity and breakers, but I am fearing there is a junction in the wall somewhere. Hopefully, it is just that one of the receptacles on the opposite side of the room is unintuitively the connection point for this receptacle.

Thanks for the responses. Hopefully in about 8 hours I'll be able to track this down and report that it was just a bad connection somewhere...

The advice given here was correct. It was a loose neutral wire in a junction box in the next room. It took quite a while for me to find it, but once I did, sure enough, loose white wire. In the process, I really secured every other connection on the circuit, so I guess it was worth the effort... :o

Thanks for the responses guys...

What will happen if neutral breakage occurs?

Opening a neutral breaks the circuit.

Would a loose neutral cause the power to that circuit to momentarily cut out, but not trip the breaker?

Yes.

I had the same problem with power loss, but no tripping of breaker. On a switch for an overhead light, I fould that a ground wire was not attached. Could this be the issue?

No. The bare ground wire is not really part of the Branch Circuit. It's purpose is to provide a low resistance path in the event of a fault.

Neutral, however, is part of the Branch Circuit. It's purpose is to provide the return path to the supply. If Neutral opens, there is no complete circuit, the circuit is open and cannot function as designed.

Quote:

Originally Posted by donf

No. The bare ground wire is not really part of the Branch Circuit. It's purpose is to provide a low resistance path in the event of a fault.

Neutral, however, is part of the Branch Circuit. It's purpose is to provide the return path to the supply. If Neutral opens, there is no complete circuit, the circuit is open and cannot function as designed.

I did find a wire (black one) one the back of an outlet that was not pushed into the back all the way and there is some bare wire showing. Could this finally be it?

Thanks so much for your help.

Back stabbing a receptacle is the worst possible connection method. Over time the spring loaded latch weakens.

Better to kill the branch circuit, remove the back stabbed wires and use the screw connections on the side of the receptacle.

Quote:

Originally Posted by donf

Back stabbing a receptacle is the worst possible connection method. Over time the spring loaded latch weakens.

Better to kill the branch circuit, remove the back stabbed wires and use the screw connections on the side of the receptacle.

Will do. I do have the breakers off to the room and tested each outlet before I remove the cover. So, do you think this will cause my intermittent power loss?

If you found one loose connection, you will more than likley find more.

Quote:

Originally Posted by donf

If you found one loose connection, you will more than likley find more.

Ok, last question: since there are 2 black and 2 white I am not sure if I can use both on the outlet?

The 2 whites can go on the white or light colored screws, and the hots to the dark colored screws.
Or you can twist together with a pigtail and connect to the receptacle with 1 hot and 1 neutral, I most always do that unless the box doesn't allow a wirenut.