Minimum wire size for doorbell?

Aug 07, 2005 7 Replies

The system uses a 24V transformer. I am not sure of the current draw. I have extra 24 gauge wires available from an old phone system and I'd like to use them (I won't have to rip open any walls.) I'm guessing 24 gauge is "probably" okay but not the best. (I can't pull the old phone wires and install a new 18 gauge (???) cable, there are too many staples along the path.)



What is the normal wire size for this situation?


Greetings,

Most phone cord has 4 wires (some has two). You can combine two and two of these wires to help eliminate your concerns.

Hope this helps, William

Hi, If bell works with existing wire it should be OK. Bell is not used all the time. Does not draw current all the time. Tony

Greetings,

If you have too much voltage drop simply use an 18 V buzzer or even a

12 V buzzer instead of the 24 V buzzer you were originally going to install. It is a lot easier to substitute a different buzzer than to open the walls.

Hope this helps, William

William

It is more a factor of distance than current. If you have a long run that 24 gauge may have too much voltage loss and the bell may not function properly.

Good grief, lots of answers here, eh?

24 gauge should do fine for a doorbell buzzer. It's easily capable of 0.1A over a long run and is even bigger than some of the supplied wiring on new bells these days.

One can add a simple circuit, consisting a resistor, diode, and a

2000-5000mfd 35vdc capacitor.

A single diode to convert the 16vac into DC, to charge the capacitor. A tens of ohms to limit the current thru the diode.

Connect the door bell circuit to the capacitor, it will ring with real authority, as the capacitor discharges. The capacitor will take a second or so to recharge before it is ready to ring again.

The values of the electronics parts isn't critical, so you can use what ever is available.

Another option is to use a 24v relay to activate the bell. the button circuit only has to carry enough current to pull in the relay.

We used a setup like this at a radio station that I worked for. The circuit ran over 10kft (~2miles) on 22 gauge telephone wire. The circuit was used to provide positive control of the transmitter, so that a cable cut would not leave the transmitter on the air. The same cable carried the program audio, and phone lines from the studio PBX..

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