Tracing 120VAC Broken Wires

1990C4S · 10-29-2018, 11:04 AM

I have several 'dead' circuits in my house; it would appear that I have lost the 'live' side feeding a circuit, I do not have power to either neutral or ground. This problem affects lighting and receptacles from the front of my house to the back, it is very annoying, but likely only one circuit.

I am guessing that the problems are all related, i.e. if I find the broken wire everything downstream will work again. I am also hoping/assuming that the problem is between dead light fixture closest to the panel, and the panel.

I have checked both of my circuit breaker boxes, I don't think it is a breaker turned off or a loose wire. Everything checks out with a voltmeter.

I have had good success tracing vehicle wires with a 'fox and hound', I have had zero success chasing 120VAC wires in a wall or ceiling.

I need to trace the (possibly) broken wire back through the garage ceiling to the panel and see if it is broken in between. I do not want to break into the drywall hoping I am right.

Can anyone recommend a good 120 VAC wire tracer? Maybe this?

https://www.amazon.com/Greenlee-701K-G-Professional-Probe-Tracing/dp/B0042VII7A?ref_=fsclp_pl_dp_5

Pazuzu · 10-29-2018, 11:29 AM

What if it's outside? We just had one of the aluminum lugs that connects the transformer to our weather-head crack, lost half the house power. Yours might be underground, but that's the fist place I'd look if I lost half of a house like that.

look 171 · 10-29-2018, 11:33 AM

I bet its one of your connection in the j box. Loose wire nut? how about checking the breaker to see if there's power coming through. Wires don't normally break. Its a bad connection.

asphaltgambler · 10-29-2018, 11:41 AM

^^^^^This^^^^^ - I had an issue tthat would come and go. Turns out - 1 of the 2 120v lines coming in to my service box from the pole had the insulation damaged when they were buried. The distance from the pole to my foundation was only @30 ft.

So when the ghosts in the wiring came out - I took a volt meter to both main incoming lugs - the bad 1 only showed @40v. That was the problem.

Power company comes our, digs it up in that area. Looks as if water would contact the exposed cabling and literally arc'd until the wires were eaten away

carambola · carambola's Garage

Your problem is inside the outlet box. A backstabbed receptacle has heat cycled enough times to not make the connection anymore. A quick easy way to find where the problem lies is to - turn the not working lights on and then "thump" the front of the working receptacles with your hand. One of them will make the lights come on. Open that box and replace the receptacle, please wrap the wires around the terminals when replacing.
I hope this helps.

dad911 · 10-29-2018, 11:47 AM

Start at the panel, and make sure all circuits have power. As stated above, could be a bad leg supplying the panel. Use a 110/220 test light, one lead on common (where the white wires connect) and check the screw (output) of each breaker.

I've also seen breakers go bad, and even though on, there is no power out.

You need to start at the beginning.......

onewhippedpuppy · 10-29-2018, 12:01 PM

Quote:

Originally Posted by dad911

Start at the panel, and make sure all circuits have power. As stated above, could be a bad leg supplying the panel. Use a 110/220 test light, one lead on common (where the white wires connect) and check the screw (output) of each breaker.

I've also seen breakers go bad, and even though on, there is no power out.

You need to start at the beginning.......

Me too. I've had multiple older breakers show good per the breaker position, but not actually pass current.

The only time I've ever experienced wires actually breaking without any other action is aluminum wiring that was not properly protected for corrosion breaking off at connections. But even then it did not fail within the wall because it was protected by the wire sheathing.

1990C4S · 10-29-2018, 12:06 PM

My problem is not the incoming voltage, both legs have 120VAC. It is not outside, I wish it was.

I have checked every leg of every breaker, they all provide 120VAC. So it does not appear to be a breaker.

I have tugged on every breaker wire connection, it is probably not a loose wire on a breaker.

It is entirely possible that the problem is in another junction box. None of the receptacles, switch boxes, or light fixtures I have examined have power; so while the problem may very well be a 'junction', I still need to locate that junction box with the bad connection.

I was a bit too general with 'broken wire', it could easily be a marrette problem, I should have stated that.

I still think I need a 'tracer' of some description.

1990C4S · 12:11 PM

Quote:

Originally Posted by dad911

Start at the panel, and make sure all circuits have power. As stated above, could be a bad leg supplying the panel. Use a 110/220 test light, one lead on common (where the white wires connect) and check the screw (output) of each breaker.

I've also seen breakers go bad, and even though on, there is no power out.

You need to start at the beginning.......

Done, that's where I started. It is not a bad breaker or a loose wire under a breaker. I checked the voltages with a meter...

Quote:

Originally Posted by carambola

Your problem is inside the outlet box. A backstabbed receptacle has heat cycled enough times to not make the connection anymore. A quick easy way to find where the problem lies is to - turn the not working lights on and then "thump" the front of the working receptacles with your hand. One of them will make the lights come on. Open that box and replace the receptacle, please wrap the wires around the terminals when replacing.
I hope this helps.

The receptacles are not back-stabbed.

I do not have power in the box.

1990C4S · 10-29-2018, 12:18 PM

Quote:

Originally Posted by look 171

I bet its one of your connection in the j box. Loose wire nut? how about checking the breaker to see if there's power coming through. Wires don't normally break. Its a bad connection.

This is the most likely source of my problems, the issue is I don't know what box it is, it is ont one of the dead boxes, it is upstream, and the house is new to me. I don't even know where all the boxes are.

1990C4S · 10-29-2018, 12:24 PM

Sorry, not trying to be negative, I appreciate the replies...but I've done a lot of legwork to get here...I know what the problem isn't...

onewhippedpuppy · 10-29-2018, 01:19 PM

I would try pulling every dead outlet or switch and checking for power, starting with the one closest to a breaker box. Figure out where you have power coming in, but not power going out. Or power going out of a box, but not making it to the next box. If you have a dead wire you can verify point A to B by disconnecting both, jumping one side, and using a continuity test on the other to insure that the wires run between these boxes. If the electrician was any good the routing should be logical.

I bet (hope?) that you'll find an obvious smoking gun when you start pulling outlets and switches.

1990C4S · 10-29-2018, 01:29 PM

Quote:

Originally Posted by onewhippedpuppy

I would try pulling every dead outlet or switch and checking for power, starting with the one closest to a breaker box. Figure out where you have power coming in, but not power going out. Or power going out of a box, but not making it to the next box. If you have a dead wire you can verify point A to B by disconnecting both, jumping one side, and using a continuity test on the other to insure that the wires run between these boxes. If the electrician was any good the routing should be logical.

I bet (hope?) that you'll find an obvious smoking gun when you start pulling outlets and switches.

I've opened every dead box, none have power. So next I need to look for a box with power, where the 'outgoing' line is dead. Easier said than done, but I suspect, as suggested above, it's a back-stabbed receptacle.

The problem is the garage is the likely place for the problem to 'start', and a) there are a ton of outlets/boxes b) a lot are covered by benches and unpacked boxes.

That's why I am looking for a tracing tool, I want to work backwards from what I suspect is the first dead box. The alternative is to investigate all the functional outlets and hope the dead circuits start working...

Gogar · 10-29-2018, 02:40 PM

Do you know which breaker is 'supposed' to be feeding these dead boxes?

You could always get a roll of wire and (with the power off) do continuity tests from one box to the other to see if they are all on the same circuit, or a few circuits, whatever

If you know which breaker it is you could always (with the power off), pull it and swap with an identical breaker from the panel and see if anything changes.

wdfifteen · wdfifteen's Garage

Good luck. You seem to know the problem - it's a connection in a junction box or a device box. You just have to start opening up boxes. It could be in a box where the device itself is functioning.
I certainly hope the problem isn't between two boxes. Been there, done that!

What are the chances?

cabmandone · cabmandone's Garage

I'm trying to follow this, you have lights that aren't working and plugs right?
If you have an issue with lights and plugs I'd suggest checking in the ceiling boxes. A lot of electricians would source through the a ceiling box then down to the switch and one to feed the plugs in the same room. My guess is you lost connection in a J box. Are you checking power from positive to neutral or positive to ground. If the neutral wire is broken you'll show no voltage when checking positive to neutral but you'll show voltage going positive to ground with a volt meter.

carambola · carambola's Garage

I've had luck with a product similar to this:
https://www.homedepot.com/p/Ideal-Tone-Generator-and-Amplifier-Probe-Kit-33-864/203761568
Good Luck and don't use on live circuits.

GWN7 · 10-29-2018, 05:55 PM

Do you have copper or aluminum wire in your house? Aluminum wire can work it 'self loose and kill a circuit. This happened at my DIL's brothers house. They lost a bedroom ceiling light, bathroom ceiling light and 4 wall plugs. I traced it to a loose wire in the bedroom ceiling light switch and once tightened everything came back on. Good thing the part of the house that had no power had a unfinished basement so chasing the wire runs wasn't that hard. I used a circuit power tester that looks like a pen. Chirps if there is power in shielded wire. Works well in the NMD type wire (plastic coated) but not so well in the paper/asphalt coated wires. I just used it to replace a stretch of wire from the fuse panel to a outdoor plug. No oblivious breaks or damage to the wire (copper 14/2) but in a 10' length it quit working for some reason. Easier to pull a new wire than splice it.

GWN7 · 10-29-2018, 06:00 PM

Here's the one I use: https://www.princessauto.com/en/detail/non-contact-voltage-tester/A-p8436727e

MBAtarga · 10-29-2018, 06:02 PM

I'm curious the age of the house. Could this issue be caused by a tripped GFCI outlet and that outlet's power was used for other outlets (expected) - but also for some room lighting as well?

Normally lights and outlets are kept on separate breakers so that room lights won't go out when a circuit breaker trips from an overloaded outlet.