Cat 5 phone jact rj voltage

Have a friend of mine that asked about modifying an old equipment for some shades and he asked about the voltage for the rj connectors that went to the extisting switch.
the old circuit board is bad is the reason for the change and the parts are so old that they dont make them any more or have a suitable replacement.

He wants to use a control 120v transformer step down to 12 volts ac, feed it through the exitsting cable (cat 5 26 awg) to the switch and install a couple relays (12volt coils) to control the up down control of the shades.

I believe most rj45 connectors cable is size 26 awg and can handle 12 vac no problem and the amp draw on the coils of the 2 relays will be no issue. The distance appear to be a problem to me though as these look like almost 60ft runs (at 12 volts).

Is there any NEC issues he needs to be concern about on this change?


Senior Member
Sr. Electrical Engineer
Given that battery is 48VDC and ringing is 90V AC for POTS, and POE is 48V DC nominal, 12V should be no problem.