wiring a control relay
wiring a control relay
(OP)
Hello
Is there any code requirements for using 24 volts and 120 volts on two separate set of contacts of same control relay? I want to keep them separate but I am being questioned by some guys working along with me.
Is there any code requirements for using 24 volts and 120 volts on two separate set of contacts of same control relay? I want to keep them separate but I am being questioned by some guys working along with me.





RE: wiring a control relay
There are code issues about separation and isolation with regards to medical equipment, but "low voltage" in that realm is 10V or less.
There are UL listing issues with regards to "limited energy circuits", wherein the 24V may need to be sourced from a "Class II transformer", meaning no more than 100VA available on the circuit in order to avoid having to have the devices it feed be UL listed. But I still don't think that precludes connecting the circuits on the same relay.
So in a word, no.
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RE: wiring a control relay
RE: wiring a control relay
Bill
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"Why not the best?"
Jimmy Carter
RE: wiring a control relay
Have a look at the contol board in a modern residential A/C and heating system. The 24V control circuits terminate to the same board as to 120V fan power wiring. Not a problem.
If you want to review detailed rules, get a copy of UL508A or UL508 standards.
Best to you,
Goober Dave
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