I have purchased a Ubiquiti UniFi G4 Doorbell and its requirements say that it needs AC power instead of DC.
I understand that Cat6 cables are just copper and can effectively carry electrical signal, but what I'd like to know is if it is safe to run 24 VAC over them.
This is the power supply that I have purchased for the doorbell (which I have confirmed works and this is the spec sheet for the doorbell.
If Cat6 cable isn't ideal for this use, what should I be looking for when purchasing cable?
what I'd like to know is if it is safe to run 24 VAC over them.
Cat6 cable will be fine for that voltage. PoE (power over ethernet) systems run up at 48 volts DC and they transport that voltage on Cat6 cable. The peak voltage of 24 volt AC is 33.9 volts so, it's well within the requirements for Cat6 cable.
This Cat6 cable states that the peak voltage can be 230 volts: -
You didn't mention current handling so I'm assuming you have this under control.
Be careful. Reading the 1st answer, I see POE is rated for 48V DC, and ubiquiti specifies 24V AC. I have seen similar questions for thermostat wire, and professional HVAC techs state not to use Cat 5 or Cat 6 wire for a thermostat.
AC specs are different than DC specs. The problem isn't that the ubiquiti doorbell needs more than POE level power. It is that the transformer will send 24 volts AC over 24 or 23 AWG wire Cat 5 or Cat 6 data cable and a little kink in the wire could be enough to ruin the voltage to the doorbell. So, I searched AWG for 24 volt doorbell transformer, and the charts show 20 AWG for low amp, 50 foot run, and 18 AWG wire for higher amperage and/or long runs. Its not the doorbell that needs larger wire size, its the transformer. Note: 18 AWG is larger than 22AWG wire. 22 AWG wire is larger than 24 AWG, etc. See link below.
Cat 6 cable will probably handle much higher voltages that its spec suggests. It would be quite difficult to make a sensible cable that broke down at 25 or 50 V AC. It's not the voltage you need to look at but the current. The bell spec. is confused, but if we take the statement 16-24VAC, 20VA, 50/60 Hz, the current with 24 V supply is 20/24 = 0.83 A. With 24 AWG, that's 2616 A/sq.inch. 24 AWG is rated to carry 7 A, but that would be running very warm. 0.83 A is well within its rating. You have plenty of volts to spare over the 16 V minimum, so wire resistance won't matter unless you are running about 100 yards of cable.
