I've been pulling my hair out trying to find my current doorbell transformer in order to upgrade it for a nest doorbell. I believe to have found it attached to my electrical panel after taking the cover off, but seemingly inside of the wall.

Electrical panel


I believe this is the doorbell transformer but I'm not 100%. I see that it is wired to the same circuit breaker which does power the existing doorbell, and it looks like a transformer but I cannot get the greatest view. Is this definitely the doorbell transformer and is there an easier way to access it without cutting the wall?

  • While you're in there, figure out why there's a white wire attached to a circuit breaker. Inspectors don't like to see that because the latest rules require colored tape at both ends. Oct 20, 2022 at 1:14
  • what Robert said, but gray wires also, and also taping is not allowed for conduit runs.
    – Jasen
    Oct 20, 2022 at 1:45
  • I agree, current code requires gray wires to be reidentified, but not sure how many inspectors would notice it. I'm more concerned about the transformer being installed with black neutral wires (not allowed smaller than 4 ga). The wire going to the breaker looks like it could be 18 ga or smaller and the breaker is rated 15 A. Oct 20, 2022 at 1:55
  • @RobertChapin the rating is 15 amps. Should I also replace those wires with thicker guage? Oct 20, 2022 at 2:01
  • Yes I found the link to the full-size photo while editing my previous comment. Any circuit conductor on a 15 A breaker must be 14 ga or larger. Ideally, get some black and white THHN for this little project. You've also got some issues on the grounding bar where it looks like there are 6 individual wires under a single screw in two places. These screws are typically rated for 1 to 3 wires. And that medium stranded wire with the white insulation... it's NEUTRAL and should never be attached to the ground bar. Oct 20, 2022 at 2:07

2 Answers 2


In all probably, it is the transformer and is the only device fed from the breaker. The drywall was added after the transformer was installed so you'll have to remove part of the wall to get to it. Then frame a small access panel so you can gt to your new transformer in the future. You'll need to turn that breaker off to remove the transformer.

  • Best way to be sure is to turn off the breaker and see if your doorbell still works. Oct 20, 2022 at 1:12
  • 1
    @GeorgeAnderson Hi there. The OP does state that the tx is wired to the same breaker that does power the existing doorbell.
    – JACK
    Oct 20, 2022 at 1:17

You are correct.

It does look like the Transformer.

Unfortunately the only way to access it, would be to cut the dry wall.

Be careful not to cut wires, use a utility knife with adjusted depth to the thickness of the dry wall.

  • @ruskes Why do you keep changing your "name"?
    – JACK
    Oct 20, 2022 at 1:25
  • @JACK it is not me, there is a bug in the system, trying to solve, after joining woodworking, my profile here got corrupt, lost my original log in and have wired messages and points. Now stuck with user12622
    – Traveler
    Oct 20, 2022 at 1:45
  • I too have had login problems. Every time I open the site, it want's to do a password recovery. I try that and never get the email. But oddly enough, when I click on my G icon (for George) I get in no problem, and can interact as usual. It's annoying, but I have no idea who to contact to resolve the problem. Oct 20, 2022 at 4:10
  • @GeorgeAnderson I have been trying to use this diy.stackexchange.com/contact
    – Traveler
    Oct 20, 2022 at 4:12
  • There is a Moderator that responds on diy.meta.stackexchange.com
    – Traveler
    Oct 20, 2022 at 4:15

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