Last updated 2026-08-28
Fixes
Why your doorbell transformer keeps burning out
Replacing the same part twice is infuriating, and it is also the clue. The second one probably didn't fail for the same reason as the first. Something else is still wrong, and the checks below will usually find it. The first one is just reading the label on the transformer, so it costs nothing to start.
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The short version
An old doorbell button only pulled power while someone was pressing it. A camera pulls power all day, because it stays on Wi-Fi and records. If your wiring predates the camera, the transformer behind it was probably sized for that old button, and plenty of houses still have exactly that.
Ask that small transformer to run a camera around the clock and it runs hot. Hot is what kills it. Drop in the same part again and you have bought yourself the same failure.
Check this before you buy anything
If it burned out with the doorbell disconnected, stop reading about sizing. A transformer that fails with nothing attached has a short somewhere in the wiring, and a bigger one will just push more current into it.
Work out which of the two it is
Disconnect the doorbell and wait
Take the camera off the wiring entirely and leave the transformer powered for a day. If it still gets hot, hums badly or trips, the fault is in the wiring and the rating is a red herring. Skip to the short-circuit section.
Read what is printed on the transformer
It will state a voltage and either a VA rating or an amperage. Volts multiplied by amps gives you VA. This one number decides everything that follows, and it is usually stamped on the body or on a small label beside the terminals.
Compare it against what your doorbell asks for
The requirement is set by the model, and the spread across one brand is wide. Check the figures below against the printed rating before you buy anything.
What the manufacturer requires
These are Ring's published figures. They're worth reading closely, because people quote one number as though it covered every model. If you run a different brand, find the equivalent page for it and use that instead.
- Battery doorbells and Video Doorbell Elite: 8 to 24 VAC, 50/60Hz, 5VA to 40VA
- Video Doorbell Wired: 10 to 24 VAC, 50/60Hz, 8VA to 40VA
- Video Doorbell Pro, Wired Video Doorbell Pro and Wired Doorbell 2K Plus: 16 to 24 VAC, 50/60Hz, 10VA to 40VA
- Wired Doorbell 4K Pro: 16 to 24 VAC, 50/60Hz, 10VA to 40VA
Why an old 10VA transformer is the usual culprit
A transformer sized for a chime is commonly 16 volts at 10VA. Against the list above, that's below the minimum for every Pro-class doorbell, and only just inside the range for a plain wired one.
It will often work at first, which is the trap. A doorbell that boots, connects and answers the app looks installed. What you can't see is a component running near its limit around the clock, getting warm, and aging fast.
When the fault is a short
Repeated failures with no load attached, a transformer that gets hot within minutes, or a breaker that trips all point the same way: a damaged cable somewhere between the transformer and the button.
Doorbell wire is thin, unshielded, and often stapled through joists by someone in a hurry. A staple through the insulation won't announce itself, and it can sit there harmlessly for years until the wire moves.
Transformer
Newhouse Hardware 16V 30VA doorbell transformer
A plain hardwired transformer at 16 volts and 30VA. That is the band most wired doorbell cameras ask for, and well above the 10VA a chime-era transformer supplied. Match your own model's published range on both numbers, volts and VA. More is not automatically safer. Mount it on the outside of a junction box and never inside a wall cavity: the manufacturer is explicit that it needs air around it to shed heat.
Transformer
BOJACK 16V 30VA transformer
The same 16V 30VA specification in a different body, listed for doorbell and thermostat use. Worth knowing because transformer listings come and go constantly and having a second known-good option saves a rebuild when one goes out of stock.
Test gear
KAIWEETS non-contact voltage tester
Tells you whether a wire is live without touching a terminal. The dual range is the reason to pick this one. Doorbell wiring is low voltage and the transformer's mains side is not, so a tester that only sees line voltage reads a live doorbell wire as dead. The low range is not automatic: press the sensitivity button to reach it. Understand what it is before you buy it. It cannot read a voltage or a VA figure. It tells you a transformer is powered and nothing about whether it is big enough. That question needs a meter.
Test gear
AstroAI true-RMS auto-ranging multimeter
The tool the transformer pages send you to. It reads AC volts across the two low-voltage terminals. That is the measurement telling you what arrives at the doorbell, rather than what a label printed years ago claims. Auto-ranging means you do not have to pick a scale before you know the answer. One limit: no meter reads VA directly. VA is a rating, not a measurement, so it comes off the transformer's plate while the meter tells you whether the voltage holds up.
Questions people ask
If the old one was genuinely undersized for your model, yes, and stay inside the published range for that model. A larger VA rating does not force more current into the doorbell; the doorbell draws what it needs. What a bigger transformer will not fix is a short, and it can make one worse.
Not automatically. Both sit inside the range for most current models, and the VA rating matters more than the voltage. Going above the published maximum is how you damage the doorbell or the chime rather than the transformer.
Warm is normal. Too hot to keep a hand on is not, and neither is a change you can date to the day the camera went in.
Entirely, if you leave them on battery and never wire them in. That is a real option and it is the right answer for a lot of houses, particularly rented ones.
If that didn't fix it
Fix guides do not always work first time. If yours did not, the next check depends on what you saw.
- Work through it question by question: the interview covers the same ground in order
- Check your model's published requirement: voltage, VA and diodes for 19 Ring models
Related
- The chime went silent after the camera went in (the other half of the power problem)
- Is my chime mechanical or digital? (you need this before you change anything)