update I replaced the transformer and 1 single doorbell with the ring video doorbell wired. Everything is functioning as it should. The existing chime from the standard doorbell is slightly louder with the extra voltage supplied.

I have two doorbells, both hooked to the same transformer. I'm looking to replace one of the standard doorbells with a Ring doorbell. The existing transformer says 115 V input to 10 V output. The new one supplied by Ring says 120 V input to 16 V output. Will this work?

There are only two wires connected to the existing one (it's not grounded). It then splices off to both existing doorbells. Will I be OK doing this? Will the existing old doorbell still work after I replace the Ring doorbell with one of the existing?

Existing transformer

New transformer

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    There's also the general concern about shoddy and/or counterfeit electrical parts on Amazon. I personally would not buy any mains electrical equipment on Amazon unless it was from a reputable brand, there were no reviews complaining about counterfeit items, and it was something I could verify was real. In contrast, the awkward writing on this listing makes me suspicious.
    – Reid
    Commented Apr 19, 2022 at 21:31
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    My transformer is comimg straight from the ring store on amazon. I have 2 doorbells switches and 1 chime. Just looking to swap the transformer and one of the doorbell switches with the ring.
    – John
    Commented Apr 20, 2022 at 15:12
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    Existing wiring goes from supply to transformer. (2 wires, no ground) to a splice where 4 wires come out . two wires lead to doorbell 1, other two run to the chime and doorbell 2.
    – John
    Commented Apr 20, 2022 at 15:30
  • Wait a minute! If you have one chime and two doorbell switches then this is different from what I answered. Key question: Are you replacing doorbell 1 or doorbell 2? If you are replacing doorbell 1 then my answer still applies - i.e., move the doorbell 1 switch wires to the new transformer and the Ring goes in place of the switch. If you are replacing doorbell 2 then this gets more complicated. Commented Apr 20, 2022 at 21:19
  • @manassehkatz-Moving2Codidact It sounds like he just replaced the transformer (so both switches and the chime got the new higher voltage), and physically replaced one of the button switches with the Ring unit. The chime presumably has 3 terminals: one each wired to the 2 button switches and one wired to the transformer output neutral. Are you thinking of something else in your mention of "more complicated"?
    – Armand
    Commented Apr 20, 2022 at 22:49

1 Answer 1


There are 3 issues here. The one in the title is actually the least of the concerns:

  • 115V to 120V

The US electric supply has gradually increased the standard voltage over the past century from 110V to 115V to 120V. Or rather, 2x that - 220V to 230V to 240V, with most small appliances and lighting using half that voltage. So the change from 115V to 120V is of no real consequence, and this change is within the variance that most devices can handle.

  • 10V to 16V

The output voltage of a transformer is a ratio of the input voltage. So a 115V/10V transformer is also a 120V/10.5V transformer, which is just fine. But a 120V/16V transformer is producing more than 50% higher output voltage and that may be too much for the old doorbell. Or it may be just fine. Unfortunately, finding out whether an old doorbell will work on 16V may not be so easy. It may work fine, it may not work at all, or it may be damaged by use with the new transformer (either immediate or long-term).

  • Total Output Power

This is a tough one. A new transformer will normally tell you the total power. But figuring out the old one may not be so easy. My hunch is that a new 120V/16V 30VA transformer probably has enough power to handle an old doorbell together with the new one. The catch is the Ring doorbell specs are a bit vague "10VA to 40VA".

My recommendation is to install a new transformer for the new doorbell and keep the old transformer for the old doorbell. This should be easy enough to do as long as the splice is accessible so that you can split the wiring of the two doorbells.

  • I'm assuming there is an existing doorbell chime unit attached to both existing doorbells. Isn't there an issue of whether the existing doorbell chime can handle the 16V instead of 10V? Also, won't that chime be connected to hots from each doorbell, but a single common neutral, making using 2 transformers at the same time for the two doorbells potentially problematic?
    – Armand
    Commented Apr 19, 2022 at 21:53
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    @Armand As far as whether "it" can handle 16V, I am referring to any/all parts of the existing doorbell. The switch is virtually certain to be fine and the wiring as well, so that basically leaves the chime. As far as "two doorbells", I based my answer on the assumption that there are two complete doorbells currently - each with a switch and a chime. If there are two switches but only one chime (e.g., front door and back door switches but only one chime) then my answer doesn't work - but I suspect that then the existing wiring won't work at all for the intended update. Commented Apr 19, 2022 at 22:26
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    Yes, since old-style distinct ring 2-doorbell chimes are all I've seen in my very limited experience, I assumed such a configuration. I've got that 2-button single chime setup and just bought a new replacement dual chime along with a new transformer for my Doorbell Pro 2.
    – Armand
    Commented Apr 20, 2022 at 2:16

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