I'm trying to install a new video doorbell. Found the transformer in the attic, attached to the attic outlet. There are two 2-wire bell wiring runs from the transformer - one to the chime and the other to the front door.

Well, almost. The front door bell is connected to a Romex cable - and somewhere there is a short... so, probably at the connection?

I traced the bell wire though the attic to the front of the house where it disappears into the wall cavity. It's a two-story drop, then exists as a cable.

So, do I have to cut up 2 stories of wall looking for the connection?

  • FYI, Romex is a brand name that may not be familiar to some and it's very specific when used as a product term. I've attempted to make your terminology more generic. Also, I suspect that you mean an "open circuit", not a short. Are you saying that the connection circuit is broken?
    – isherwood
    Oct 4, 2019 at 18:21
  • Is there any evidence that the entry was remodeled, necessitating an extension to the bell wire? Did your original front door bell button not work?
    – isherwood
    Oct 4, 2019 at 18:22
  • 1
    So in the attic where you followed it, was it also NM Cable (romex) or does it go from bell wire to NM somewhere in the wall? Using that for bells is not common because it's so much more expensive (more copper).
    – JPhi1618
    Oct 4, 2019 at 18:23
  • 5
    @JPhi1618 I don't know, if the choice was use 14/2 I had on the truck, or spend an hour going to the shop to spend cash money on thermostat cable... Oct 4, 2019 at 19:08
  • If they used Romex, then they probably grounded the ground wire, and you're accidentally grounding your transformer's hot or common somewhere making it not work. Since it's a bare ground wire it's easy to accidentally ground something else.
    – Dotes
    Oct 5, 2019 at 5:37

3 Answers 3


It is not common because of cost but it’s also not uncommon. I agree with Harper if I have a broken bell wire I would use something on the truck to repair the wires. Since it was repaired you may get lucky and be able to use the existing wires as a pull.

I would use a pull string , but you may have some stout fishing line that could work. The trick here is figuring out where the break or short is. At the chime disconnect the door bell button and verify you have 24v , some transformers have a bridge that converts to dc so you need to know what you are trying to measure unless your meter automatically checks for both. If there is voltage at the chime we know the problem is probably at the splice.

I would use the wires as a pull. I would tie a pull string to the bell wires and pull that direction because the bell wires are smaller and if it will pull small wires following a large cable will work easier than trying to pull the other way.

If the wires are stapled and I now know I will have to open the wall sometimes I will pull to the breaking point and the splice may pull free then I would measure the length go up to that point and open the wall, it may save a lot of repair work if you can fish the new wires down the wall.

Just to clarify the string or fishing line is used to pull new wires from the button to the chime. Pulling the wires out at the button location , hopefully until the string or fishing line arrives at the button location. Standard pull string is rated at over 100 pounds.


No, it is not common. But if it works, it certainly isn't unsafe if done right. You're real interest is how to get your new video bell working. You said the circuit has a short, but suspect you mean it is open. You should measure 24 volts AC across the two wires at the door. Make sure your volt-meter is set in the AC position. Using the DC position will cause it to read zero and give a false indication of open circuit. If you find 24 VAC, your chore is to figure out how to install the video bell. If you really do have an open (or short), then you have to disassemble your house to an extent that you can repair the problem. Often, there are components that can be removed and you can find the splice (connection) and maybe even the problem. If you don't have a solid carpentry background, it may seem like these components are all one piece or impossible to work on without lots of destruction, but a skilled carpenter / handyman could work magic.


The alternative to repairing the wire is to use a wireless door-bell. That might get expensive in batteries if you have a video door bell - but it's certainly worth considering.

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