The old doorbell in my house (previous owners) was a wireless bell/chime combo. I replaced it with a video doorbell and in doing so, noted that there was no power for the doorbell wiring at the door. I'd like to get the power working so that I don't need to remove the video doorbell and re-charge it.

The doorbell transformer is on the outside of the panel box; in removing the panel box cover, I noticed that the black lead is not connected to anything.

I'm going to assume a doorbell transformer doesn't get it's own breaker. Do I pigtail it to one of the other black leads and then run that to the breaker?

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1 Answer 1


Yes, it can be pigtailed to another circuit.

However, because you have Square-D breakers (though I can't positively identify as QO .vs. Homeline) I will mention that it is possible (as in permitted and listed) on most Square-D QO breakers to have 2 wires connected, if wiring is copper. Which might save the bother of pigtailing, as you have many breakers that appear to be in reach.

side of a QO 15A breaker

Easier to read in real life, but the illustration on the side of the breaker shows how to connect two wires (only for copper wires.)

  • Based on the size of them and the markings on that 2-pole that we can just barely see, I'm almost certain those are QO. Those stadium-stacked neutral bars are also a feature I remember from QO panels.
    – Chris O
    Sep 30, 2022 at 21:44
  • I have QO panels - I'm just not clear enough on what the differences between them are (other than quality/price) if I can't see enough of the breaker to read the HOM.
    – Ecnerwal
    Sep 30, 2022 at 21:48
  • QO are 3/4" per pole and HOM are 1" for starters. Also, the 2-pole version has the logo on one "pole" and a blank space where the other would be. Those are 100% QO breakers pictured.
    – Chris O
    Sep 30, 2022 at 22:04
  • Thanks. It appears that I can connect two wires. However, I believe the doorbell transformer black lead is the standard low voltage aluminum wiring. You can actually see it in the picture, centre of the page about 1/4 of the picture down from the top. Will this be an issue?
    – Steve
    Sep 30, 2022 at 22:11
  • Its much more likely to be tinned copper than aluminum. Regardless, Pigtail it to a normal-sized copper wire to connect to the breaker (advantage being you're not cutting up an existing circuit to pigtail to) Probably also needed to make the minimum size for the breaker connection.
    – Ecnerwal
    Sep 30, 2022 at 22:16

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