Advanced Electrical Help Needed

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

John Smith

John Smith

In the garage
10 Year 15 Year 20 Year
Joined
Jun 7, 2004
Threads
88
Messages
4,482
Location
Maryland
I need the help of the Mud electrical brain trust. I have an entire circuit that stopped working on Friday. This is a 15 amp circuit comprised of BX wiring original to my 1933 house. It services my first floor bathroom, office, and tv room. My current service is 200 amp and was upgraded a few years ago. I learned this circuit was overloaded when the new panel was installed and have been meaning to deal with it.

Well, I did not deal with it soon enough. I believe I have an issue where the hot is following the neutral path. The breaker on this circuit did not trip and will not despite the following.

Here are the readings I receive with my multitester at every outlet. I have yet to test the light fixtures.

Neutral to ground = 36V
Neutral to Hot = 86V
Hot to ground = 120V

So my non electrician guess is that somewhere in that BX wire the insulation has deteriorated to the point where the hot is now bleeding into the neutral wire?

I know the BX wire is at end of life and I will need to run new romex to replace it. Lucky for me the basement is unfinished and it won't be too much hassle to pull new romex from below for the outlets. What seems like it is going to be a PITA is fishing new wire to the 3 ceiling fixtures and down the wall to the existing switches.

If anyone can offer any wire fishing tips for ceiling fixtures or in general I would appreciate it. Also does it sound like my diagnosis is correct? I would like to perform the wiring work myself then have an electrician check my work. I am very comfortable working with electrical wire and have successfully wired my garage previously to code.

Thanks!
 
The only tip I could offer from this distance is don't be afraid to tear some holes in your walls. Fish sticks are very helpful in some situations- they are 5 foot fiberglass rods that can be threaded together for longer lengths, and hooks or loops threaded to the ends to pull wires with.
 
Koffer said:
Is this with a load on it ?


you could have dirty /burned connections somewhere . could be a bad / loose screw on a outlet or wire nut .
Click to expand...

Yes, the voltage readings above are with load on the circuit. I have checked all the outlets and they all read the same voltage. I get 120 at the breaker in the box so the issue is somewhere along the path post panel. I am going to check the ceiling fixtures for arching or any other things amiss tonight.

Remembering back years ago when the kitchen was gutted and remodeled I seem to remember all the wires ran from the light fixture down to the outlets in the walls. Perhaps that is how they ran wire back then. This is what that fire hazard looked like. I hope to find the issue in one of the ceiling fixtures. In the picture are 5 BX wires into a 3" x 1 1/2" box.
kit 118.webp
 
Update!

This past weekend I was able to test all the wires on the circuit and found that the neutral wire from the panel to the first fixture was indeed bad. When removing the wire from the panel I found it had partially welded the screw to the bus bar. Yikes! That breaker went in the trash. I ran a new feeder wire and everything works again on the original circuit. I also added two new 20 amp circuits to take the load off the old existing BX wire.

While in the breaker panel I found the electrician who did my heavy up simply put the four existing original circuit BX wires into their places without cleaning the 77 years of oxidation off. The wire ends were black. So I spent some time with fine emery making them shiny copper again. I guess the inspector was in awe of how clean the rest of the work was and overlooked the original work.

Anyway, glad to have it resolved without a electrical fire.
 
good to hear....

remember - professionals built the titanic, amateurs built the arc :grinpimp:

kinda scary thinking what could've happened with some of that wiring.
 
Depending on when and who wired your place, it is possible that at every switch and outlet, the wires were stripped and shoved into holes in the back of the device. In these holes are little springs which bite the wire. They wear out. Over time and use, the springs become weak and let go- or bite just enough to give voltage, but not to carry a load. I have seen this HUNDREDS of times in houses I have troubleshot. Sometimes i can pull the plug out of the wall and find the whole mess of wires still sitting where they were before I pulled the plug out! In cases where you have more than one wire on each terminal, I recommend splicing them w/ a wire nut and add another wire(pigtale) to the bunch to take only ONE wire to the SCREW terminal of the device. This method is current NEC. When faced w/ your situation, I always start in the box in question, and try to find the next box upstream in the circuit. Keep working upstream till you find it. Also the terminals in an older panel should be retorqued every 10 years or so. That was a good catch on the loose neutral. Heat is the byproduct of resistance. HTH
 
Pin_Head said:
Sounds like it is time to pull new wire. Some really old wire is open wires on ceramic insulators. If the old wire is not tied down in the middle you may be able to use it to pull new cable.
Click to expand...


Knob and Tube. Seen it still in use. SCARY.
 
LAMBCRUSHER said:
Depending on when and who wired your place, it is possible that at every switch and outlet, the wires were stripped and shoved into holes in the back of the device. In these holes are little springs which bite the wire. They wear out. Over time and use, the springs become weak and let go- or bite just enough to give voltage, but not to carry a load. I have seen this HUNDREDS of times in houses I have troubleshot. Sometimes i can pull the plug out of the wall and find the whole mess of wires still sitting where they were before I pulled the plug out! In cases where you have more than one wire on each terminal, I recommend splicing them w/ a wire nut and add another wire(pigtale) to the bunch to take only ONE wire to the SCREW terminal of the device. This method is current NEC. When faced w/ your situation, I always start in the box in question, and try to find the next box upstream in the circuit. Keep working upstream till you find it. Also the terminals in an older panel should be retorqued every 10 years or so. That was a good catch on the loose neutral. Heat is the byproduct of resistance. HTH
Click to expand...

I actually ran into an electrician I know at Home Depot on Sunday when I was buying more supplies to run even more new circuits. He told me the issue was most probably caused by the neutral wire not being secured in the panel properly. The loose screw made it lose contact and allowed it to start arching which took out the neutral wire. Makes sense to me. I retorqued all the screws in the panel and found 3 more not tight enough. I guess I will add that job to my once every 10 years To Do list, along with the tetanus shot.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom