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Any ideas what this twisted pair of wires did before I split them?

Any ideas what this twisted pair of wires did before I split them?


Old 12-08-11, 09:12 PM
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Join Date: Aug 2011
Location: USA
Posts: 62
Any ideas what this twisted pair of wires did before I split them?


So, I was drilling a hole to run some of my new romex cables, and split a pair of twisted wires with my drill.

These twisted wires were twisted around a nail on a rafter that would be at the top of the first image below, and is just off screen to the right on the next two images.

It's a hard area to look into. I looked good enough to see there was no electrical cable running where I was drilling, but should have looked more to catch this.

As a temporary fix, I've separated the black and white wires from each other and electrical taped their ends (separately, of course.)

As bad as the electrical has been in my house, I can't see these running 120v electricity.

This is at the back of the house. I can't trace one direction well because it goes into the brick exterior wall. I can't easily trace the other direction because someone put up a cheap stapled ceiling instead of an actual drop ceiling.

My first thought was that it might be the wire between the thermostat and the air conditioning. But, I was able to turn on the air conditioner for a moment. (Never done that before when it was 32 degrees out.) Furnace works fine, too.

The only other thing I can guess is that it might be a back doorbell wire. There isn't a back doorbell, and wasn't one when we bought the house, but maybe there used to be.

This is in a basement, it's a family room sized room.

Anyone have any idea what these are?

Would you re-connect these? I figure I could always split apart 6" of my 12/2 cable to get the black and white wires, and wire nut at both ends.

Would you trace it back to figure out what it is for, even though this means ripping apart a ceiling that you can't put back up?

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Old 12-08-11, 10:11 PM
Join Date: Oct 2008
Posts: 1,312
Usually those are doorbell or thermostat.
Old 12-09-11, 09:46 AM
Join Date: Jul 2007
Location: USA
Posts: 417
Quite a puzzle!
Please clarify:
Were the wires attached to each other-as in a possible electrical connection, or were they both twisted around the nail, but not connected to each other?

Was the nail,well... nailed into the rafter, or hanging loose??

It might be my computer, or my eyes, but those wires- especially the "white" wire-or the light brown wire- appear to be cloth coated, rather than rubber insulated-which might indicate that they are older wires.

Possible explanations:

As others have said, bell or thermostat wire, possibly speaker wire?

Wire disconnected from the circuitry, but left in place" just in case they are needed for the future"

Wires used to pull other wires through a wall/ floor cavity-but where are those wires ??

Have you found out what circuit, if any, that those wires are connected to?

Good luck with this. Please let us know what you find.
Old 12-09-11, 10:12 AM
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Join Date: Sep 2005
Location: USA
Posts: 4,059
I'd lean towards a back door doorbell. Do you see similar wires at your doorbell or at the doorbell transformer?
When you turned on the AC, did the condenser outside actually turn on?

I'd probably leave them disconnected and see what doesn't work in the future.

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