rjk_cmh
Member
Trying to figure out the best way to take accept a PLC input from an existing 120VAC lighting circuit in order to detect when the lights are on. I see 2 possibilities since my PLC is 24V AC/DC:
1. Use a relay
2. Use an optoisolator
What I want to know is how should I go about protecting either of these? In this case, the voltage is not being fed by the panel's control transformer, and therefore it has a much higher available fault current - the lighting is fed from a 20 amp breaker.
Is it safe to use the little terminal block style fuse blocks that take glass fuses, or do I need to upgrade to midget fuses? Time delay or fast acting? What rating? Maybe I don't need to bother with fuses at all?
1. Use a relay
2. Use an optoisolator
What I want to know is how should I go about protecting either of these? In this case, the voltage is not being fed by the panel's control transformer, and therefore it has a much higher available fault current - the lighting is fed from a 20 amp breaker.
Is it safe to use the little terminal block style fuse blocks that take glass fuses, or do I need to upgrade to midget fuses? Time delay or fast acting? What rating? Maybe I don't need to bother with fuses at all?