I have existing wiring for my doorbell that goes from the front door to a closet. No actual doorbell or chime is hooked up, just wiring. When I connect a 24v transformer to the closet end, I'm detecting very low to non existent voltage at the front door.

Just a note, the existing wire is a, i think, cat 3 wire. It has 6 total wires, pair solid and stripped blue, green and orange wires which i believe are 24 awg. The construction contract probably went cheap and saved a few pennies with these wires since the distance is no more than 50 feet.

I did do some googling and tried a few things listed below with no luck. Any help recommendations is appreciated.

  1. Installed 24 Volt transformer (multimeter detected ~28), connected 1 wire each to the 2 screws on the transformer, doorbell detected ~0 volts
  2. Installed 24 Volt transformer (multimeter detected ~28), connected 3 wires (twisted together) each to the 2 screws on the transformer, doorbell detected ~2 volts
  3. Tested continuity. Twisted 2 wires together where the doorbell is and tested near the transformer with no luck. Multimeter got no beeping noise.
  4. Tested resistance with the same setup as above. I get 0.5 M ohms.
  5. Tested with a wire tracer/tracker to make sure the wire is correct. I do get noise from both ends. Not sure why this is working with the super high resistance, but it is working...

FYI: I'm using Wire Tracker Tacklife CT01 and Klein Tools Auto Ranging MM400.

I'm stumped on this. Not sure what else to do besides calling an electrician and having him re-wire with a proper bell wire (20awg) which i'm guessing is the main issue.

  • twist all wires together at one end .... measure resistance between all possible pairs (15 combinations) – jsotola Jul 16 '18 at 17:14
  • might be a problem with mice ..... i heard that some cables have been manufactured with the outer jacket made from soy, which the mice find yummy – jsotola Jul 16 '18 at 17:20
  • @jsotola I'll give it a try. Hopefully i can get a combination with ~0 ohms. With the wire cut mid way, wouldn't the wire tracer not work? – Donny Jul 16 '18 at 17:24
  • maybe the tracer uses radio frequency signals which "jump" across cuts in cable .... maybe the tracker can find the breakpoint ..... the bad spot may be near the end of the cable .... the previous owner may have damaged it while working on it – jsotola Jul 16 '18 at 17:35
  • note: if you do have to rewire, think about future expansion like an audio/video doorbell – jsotola Jul 16 '18 at 17:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.