[JohnC20]

Hey!
I hope everyone is doing well.
My question (sorry if it's long) has to do with a little surprise I encountered when installing lights in my closets of my 90 y.o. tudor home.

A few weeks ago I tapped into existing power in the attic to run 14-2 BX to two closets for lights. Power goes to a pancake box screwed into the rafters of the attic roof that had an old pull-string light fixture that didn't work. I removed the fixture and replaced it with a single pole Home Depot unit, then I ran a power line to a single gang switch box close to the crawl hole where I gain access to the attic, and a line back to the pancake box for the fixture. This was done to install an illuminated switch so when I pop my head in the crawl hole I can flip the switch to see what's doing.
From the pancake box, I ran two 14-2 bx lines tapped into power, and snaked them to each closet ceiling from inside the attic. I drilled two holes; 4" each for the ceiling light fixtures. Once I ran the wires through the ceiling boxes, I closed up shop in the attic and made my way to the closets...

What happened next was interesting....

I had my no-touch voltage finder set on low voltage. I put it close to the wires poking through one of the closets and it buzzed. I switched it to line or high voltage and it stayed quiet. I didn't think anything of it and proceeded to install the light fixture in one of the closets. To my surprise, I was awakened by a nice jolt when I grabbed hold of the neutral (white) wire bare end as I was about to wire nut the fixture to it!! The black was not energized. This was confirmed with the voltage finder...
The breaker was off!!!
What gives?? Could it be the breaker "leaking" power? If so, why the neutral?

How should I go about troubleshooting this? (sorry for too many details!)

Thanks!!!! :thumbsup:

 

[HouseHelper]

The neutral is being shared by another circuit. Not uncommon in older homes.

 

[JohnC20]

The neutral is being shared by another circuit. Not uncommon in older homes.

Is this ok? Should I try to isolate it? or just be aware of it... I'm guessing I was hit with about 40v....

 

[jbfan]

You need to find it and beware of it.
If you disconnect a shared neutral, bad things happen to electronics!

 

[JohnC20]

You need to find it and beware of it.
If you disconnect a shared neutral, bad things happen to electronics!

Ok, since I am aware of it, should I leave it alone and remember the next time, or locate where it is shared and isolate it? I guess what I am asking is could this cause an overload and a fire?

Thanks for the replies!

 

[jbfan]

It could/should be code compliant, and would not pose a danger, but be aware that they do exsisit and can cause problems if tampered with.
It could also be an illeagl install.



To find out, put your tester back on it and turn breakers off until the tester show zero, and we will go from there.

It should be the breaker right above or below the one you were working on.

 

[HouseHelper]

It's been my experience in the older homes that the shared neutral will most likely be in a 3-way switch circuit. Instead of carrying the neutral in a three conductor cable, the installers grabbed the neutral from whatever was close by, regardless of the circuit.

 

[JohnC20]

It's been my experience in the older homes that the shared neutral will most likely be in a 3-way switch circuit. Instead of carrying the neutral in a three conductor cable, the installers grabbed the neutral from whatever was close by, regardless of the circuit.

This is interesting because there is a three-way switch contolling a light at the top of the stairs just outside where the closets are. The switches are located at the top and bottom of the stairs.

How would I test this? Pull the switches and see if there are two "white" wires on them?

Thanks!

 

[JohnC20]

It could/should be code compliant, and would not pose a danger, but be aware that they do exsisit and can cause problems if tampered with.
It could also be an illeagl install.



To find out, put your tester back on it and turn breakers off until the tester show zero, and we will go from there.

It should be the breaker right above or below the one you were working on.

If it's not the three-way, I will try this. Thanks!