I have a 15 amp breaker that’s used for my foyer/family room. The builders double tapped that breaker to add a 16V-10VA transformer for the doorbell to the side of the service panel via a knockout. See pics below.
I plan to swap the existing transformer with a 16V-30VA transformer to power a Unifi G4 Doorbell along with my NuTone chime box. In the process, I’d like to correct the double tap.
My question is: Do I need to worry about the wire gauge of the transformer wires if I wanted to correct the double tap via a pigtail? The AWG of the transformer is 18. As far as I know, this is not up to for code for a 15 amp circuit. Is it ok if I proceed to pigtail with the mismatched wire gauges? I understand the current transformer is also a different gauge wire and double tapped which seems to work fine, but I’d like to correct it.
My other question is: Instead of a pigtail, if I were to add another single pole 15 amp breaker to correct the double tap, would I need to worry about the wire gauge of the transformer as long as the doorbell is the only thing on that breaker?
Finally, I know it’s “common practice” to double tap for doorbell transformers, so how bad is it really if I didn’t fix the double tap?
I’m not so concerned about being perfectly up to code. Instead, I’m looking for something that is safe and reliable.
Thanks!
Best Answer
The leads for the transformer are sized per the NRTL Listing, don't worry about that.
Those breakers aren't listed for double taps, the fine print on the breaker will tell you if they are.
Minor violation being tapped to dining receptacle circuit. NEC 210.52(B)(1) includes dining area receptacles in the scope of the two or more 20A circuits that serve kitchen receptacles, and 210.52(B)(2) says they shall have no other outlets. (Hardwired connections are included in the definition of outlet.)
Probably not much you can do about a 15A serving dining area, but just add a 15A breaker, spare spaces are near the transformer, and much tidier than splices.