Broken Wire Inside the Wall

[Moon Dog]

I bought this house a couple months ago. It was built in 1952 (same as me) but has been rewired with yellow 12 awg Romex dated 2007. Looks like a professional job. When I first moved in the back door outside light worked, but it recently stopped working. It wasn't the bulb, so I checked it with a meter and got 50 volts. Then I checked the ohms from the switch to the light fixture and found the black wire has no continuity.

The wire from the breaker to the wall switch is the new Romex and that is OK. The wire from the switch to the light fixture is the old fabric covered wire and doesn't have a ground. It would have required opening the wall to replace that one so they left it. It is 12 awg also and looks to be in good condition at the ends that I can see but must be broken somewhere inside the wall, and it just happened!

What in the world would cause a wire to break inside the wall? I'm wondering if there is some sort of fancy new device that can pinpoint a break in a wire inside the wall that doesn't cost too much?

Right now I have the light working, but it is not a good fix. The white wire from the switch is taking the place of the black wire and the white wire from the light fixture is connected to a metal stake in the ground.

 

[pc1966]

It is very unlikely for a wire to break inside a wall, even if aluminium that is prone to fatigue if flexed. Most likely there is a junction box hidden somewhere.

There are ways to estimate the approximate length in to a cable where the break is, but test equipment would probably cost more than just putting in a new cable!

 

[Moon Dog]

It is very unlikely for a wire to break inside a wall, even if aluminium that is prone to fatigue if flexed. Most likely there is a junction box hidden somewhere.

There are ways to estimate the approximate length in to a cable where the break is, but test equipment would probably cost more than just putting in a new cable!

Thanks for the response. It is copper wire. If the switch was on the same wall as the light I could probably run a new wire without much problem. You see how it is in the photo and I can't fit through the attic access hole since it is only 13" square.

 

[pc1966]

You see how it is in the photo and I can't fit through the attic access hole since it is only 13" square.

What is the point of an access panel that small? Did they anticipate sending Victorian children up to fix things instead of cleaning a chimney?!

More practically, could you take the wire outside and run it around the building there? You might need to put it in trunking or conduit to keep sunlight / UV off it, or use suitably rated outdoor cable that is UV-tolerant.

 

[Moon Dog]

What is the point of an access panel that small? Did they anticipate sending Victorian children up to fix things instead of cleaning a chimney?!

More practically, could you take the wire outside and run it around the building there? You might need to put it in trunking or conduit to keep sunlight / UV off it, or use suitably rated outdoor cable that is UV-tolerant.

I don't know why the attic access is so small. It wasn't needed I suppose since there is a basement and the detached garage has an attic with stairs and a floor so the extra storage wasn't needed. On the plus side the blown in insulation is pristine, not a single footprint.

You got me thinking, the new romex to the switch tells me I can probably fish a wire up from below. I will just have to get it to the light and that wire is coming through a mortar joint in the brick.

The house has a full basement except for that 3' wide area that extended the kitchen and dining room which is a crawl space. You can see the dropped ceiling which was necessary to extend the roof. That is a tight access also but I was able to wiggle in there for some plumbing work. The trim is all made out of 1x4s so if I removed the left casing from the door there may be a wide enough gap for a wire and I would only be 7" from the light fixture.

 

[pc1966]

If you can drop it down to the basement and around that would be your best option. You might even find the existing cable there and a loose junction box!

Obviously you need to be absolutely sure there is no power before attempting any repair. Switching off at the main incomer is the safest option, killing just the breaker feeding the circuit is not as safe and you really do need a reliable means of testing for voltage first to safely isolate. Not a neon screwdriver!

Something like this (your profile says Philippines):

https://shopee.ph/KES-AT-86088-641-3in1-electrical-voltage-tester-COD-i.176595476.10641092539

Or the contact tester from this sort of deal:

https://www.amazon.com/Klein-Tools-80097-Beginner-3-Piece/dp/B0B7Z178B1/

 

[Moon Dog]

I identified the breaker already and marked it. I have a decent multimeter for testing. All the wiring in the basement is new wire. I believe the wire from the switch goes through the studs or through the attic, it goes up. I really only need 1 wire but probably better to pull a complete romex cable. I could change the 20 amp breaker to 15 amps and pull a 14 awg wire to make things a little easier. It's only a light.

I completely wired the first house I built, meter pan, panel box, all the way to the weather seal, and did it legally. Delaware was issuing permits to home owners at the time. You had to have a licensed electrician on the permit but they weren't allowed to do any of the work, only offer advice. I bought a code book and did it up right, inspector gave me an A+.

I need to change the Philippine location to West Virginia. I lived in the Philippines the past 2 1/2 years and I had some questions on the 220 volt single pole electric and never really got an answer. Some expats wanted to bring 220 volt (I know, it is actually 240 volt) appliances from the US and somehow plug them into a single pole 220 service. Do you think that would work?

 

[Megawatt]

I bought this house a couple months ago. It was built in 1952 (same as me) but has been rewired with yellow 12 awg Romex dated 2007. Looks like a professional job. When I first moved in the back door outside light worked, but it recently stopped working. It wasn't the bulb, so I checked it with a meter and got 50 volts. Then I checked the ohms from the switch to the light fixture and found the black wire has no continuity.

The wire from the breaker to the wall switch is the new Romex and that is OK. The wire from the switch to the light fixture is the old fabric covered wire and doesn't have a ground. It would have required opening the wall to replace that one so they left it. It is 12 awg also and looks to be in good condition at the ends that I can see but must be broken somewhere inside the wall, and it just happened!

What in the world would cause a wire to break inside the wall? I'm wondering if there is some sort of fancy new device that can pinpoint a break in a wire inside the wall that doesn't cost too much?

Right now I have the light working, but it is not a good fix. The white wire from the switch is taking the place of the black wire and the white wire from the light fixture is connected to a metal stake in the ground.

It possibly be a sheet rock screw. The NEC requires all holes cut in the studs should be no less then 1 1/4 inches from the studs and if any closer then a nail plate is required. Other than that there should be no reason that a cable goes bad. The wiring that you did could be very dangerous using the neutral as an ungrounded conductor. Good luck and welcome to the forum. Hope this helps