Video Doorbell Transformer Wiring Question

Hi all! First time home owner here; basically no electrical experience beyond the easy doorbell and chime. I installed one of those video doorbells at the house and need some advice on the wiring. I’ve gotten as far as knowing I need to replace the transformer, which I’ve purchased. That’s where it got complicated for me.

The dilemma: the old transformer has two wires, and the new one has 3. AND, there are two separate things wired together with copper wire (one I’m assuming is the doorbell) and both of those things are wired to the transformer. I’ve included pictures of the current wiring and another of the new transformer, with comments to illustrate. Group 1 in the current wiring is the black/white/red/copper, which I’m assuming is the doorbell, and Group 2 is black/white/copper, which I have no idea what that is. There is no back doorbell, only a front.

Here are the current connections with the old transformer:

  1. A black wire from the old transformer is capped with Group 1 black wire
  2. The other black wire from the old transformer is capped with Group 1 white wire and Group 2 white wire
  3. Group 1 red wire is capped with Group 2 black wire
  4. Group 1 copper wire is twisted with Group 2 copper wire

My questions:

  1. I’m assuming the black wire of the new transformer should connect to Group 1 black wire?
  2. The new transformer white wire should connect to the Group 1 and Group 2 white wires?
  3. Copper wires from Group 1 and Group 2 should be left twisted together?
  4. The new transformer green wire should connect to Group One red wire and Group Two black wire?

Many thanks in advance for your guidance!

1 Answer 1


Green is the same as copper/bare. It is ground and is never connected to any other wire colour.

Connect the green to the copper/bare wires only.

I think there is only only country on Earth that might use green for power/not ground in South East Asia.

  • The copper currently isn’t capped. Should I cap it with the green wire?, I’m assuming everything else I said was correct then? Commented Jan 14 at 21:55
  • 1
    Cap/nut all the green/bare together. All the rest is correct.
    – crip659
    Commented Jan 14 at 21:57
  • Thank you so much!!! Commented Jan 14 at 22:28

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