Missing neutral ?

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carter3933

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Brother-in-law called me to come fix his problem. He had attempted to replace a ceiling light fixture and a dimmer switch for that light. He was replacing the dimmer switch with a simple switch. He lives in a two-story town house.

When he turned on his breaker none of the lights on the second floor worked, which was were he was doing the work. The lights on the second floor was on a separate breaker.

What I found in the box in the ceiling was the usual -- 2 blacks and 1 white (going to switch) tied together, three whites w/ pigtail, and the black from switch.

With breaker on and wall switch on, found no voltage between black and white, but had 120 V between black and ground. Joints had tape on them, no wire nuts, so removed tape on white wires and found they had used crimp connectors on them. I cut the wires to measure to each one.

One measured ~92v to black, the other two 0v, but increased to about 90 when some of the other switches in other rooms were turned on.

Checked service to verify good connection on neutral wire, it was good.

I had to leave, good thing they wired the receptacles on different breaker. These Town homes are probably 20 - 30 years old. I plan to go back tomorrow.

Does anybody have any clues or suggestions?

Thanks,
Ron
 
Sound like your switches are backfed. Common problem. I consider bad wiring from installer but common 30 years ago.

Are there any outside receptacles? Are other switches backfed? Do the receptacles have a ground in them? If so take a GFCI plug tester and test them. It will tell you if you have a looase neutral.

I would pull other fixtures (sorry - luminaires) down to see if there are other issues.

Sounds to me like a loose neutral. You make have to take things apart to find it.
 
Back fed is a possiblity.

However, I would first look for an outlet in the circuit upstream that has a backstabbed receptacle. The neutral could be loose and/or toasted.
 
I trouble shoot stuff like that with a wiggy. The digital voltage can be misleading.


1st, find out if he did ANYTHING else.

If not, start from scratch. Check all breakers phase to phase to eliminate reading back feed. Check all neutral connections.


Next, get a "picture" of the circuit path and start opening boxes in a logical manner. Start with the recep that is used for the space heater or iron. Look for signs of homeowner rework like new switches/receps/fixtures/fans.
 
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It's a simple fix...

It's a simple fix...

carter3933 said:
<snip>
What I found in the box in the ceiling was the usual -- 2 blacks and 1 white (going to switch) tied together, three whites w/ pigtail, and the black from switch.


Ron
Click to expand...


The problem is revealed in the bold text above...one of the whites is in the wrong place.

Open the dimmer box up, tie the white and black together and find the correct pair to the switch box with a continuity tester.

Reconnect the black to the fixture and the white to the two blacks in the box.

Tie the remaining whites together, and you'll be back online. :smile:

Bet you can't guess how I know this.. :grin:
 
The problem is revealed in the bold text above...one of the whites is in the wrong place.
Click to expand...



Joints had tape on them, no wire nuts, so removed tape on white wires and found they had used crimp connectors on them. I cut the wires to measure to each one.
Click to expand...

I doubt it.....unless his brother took the wiring apart and used crimps and tape. I was assuming it was a stock 50/60's installation and was functional prior to the fixture removal.
 
Finally got it working last night.

After opening all of the light fixtures, which looked "normal", dug through the insulation in attic trying to find the cable going to the service. Saw one which looked like it was going to the correct wall, but was going under boards for crawl/storage space in attic.

In the fixture box that cable went to, cut off crimp for black wires, cut on breaker and determined it was the only one hot. It actually had 120v to the neutral? The first time I had 120v to a neutral. Twisted the blacks together (4) and put on wire nut. Turned breaker back on and did not have 120v to neutral?????

So, I had brother-in-law pull up boards to see if it was actually the cable going down the wall to the service (service on inside wall). He got one up but the other had about a thousand nails in it, so he raised it up enough to see cable going to wall header. I started to take his word, but I decided to put my hand on it. The cable fished to where he could not see it. By me following the cable with my hand, I found a splice, the worse I hope I ever see. The ground wasn't even spiced, I guess the ground had found a connection in one of the three-way boxes. Metal boxes.

While I was taking the mile of tape off, the wire nut on the neutral fell off. The wires wasn't twisted, only stuck in wire nut. No tape on that part.

Made some good joints and the lights worked.

Why this happened when he was working on a fixture not physically tied to this cable is strange.

Thanks for the responses.

Ron
 
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