Different voltages in same conduit.

[bgelectric]

So im confused on when wires of different systems can share the same conduit.
I was under the impression that I can share a conduit of different voltages as long as all the wires have the same voltage ratings. exp 600v thhn.
Id like to run 1ph 120v 20a power, 3ph 208v 20a power and wire for a set of dry contacts in one conduit.
Could someone please clarify this for me with code references.

 

[Ponchik]

You are OK to install wires from different volatges in the same conduit. As long as they are identified properly. 277-480 in the same conduit as 120-240

 

[bgelectric]

Is there a code violation for running wiring from a set of dry contacts through the same conduit?

 

[darekelec]

nope. just treat it all the way as class 1 circuit. see 725.48

 

[hurk27]

The dry contacts will depend upon the load or signal they are controlling, we run 120 volt I/O's on our PLCs and most time have no problem with capacitive coupling as long as the run is not too long, but if the dri contacts are controlling something with a much higher impedance this could cause problems, some electronic inputs such as electronic timer relays or other electronic controls can be falsely signaled from ghost voltages caused by capacitive coupling even if they are signaled by 120 volts.

 

[infinity]

If the dry contacts are part of a Class 2 circuit they cannot be in the same raceway as the power conductors regardless of their insulation value.

 

[GoldDigger]

If the dry contacts are part of a Class 2 circuit they cannot be in the same raceway as the power conductors regardless of their insulation value.

If the dry contact circuit is wired from end to end as Class 1, then you could choose to classify the circuit as Class 1 instead. And Class 1 circuits can share many types of raceway if they are functionally associated with the power conductors they are sharing with.
Some inspectors have gone so far as to argue that the remote control wiring to a generator is not functionally associated with the power coming from that generator, so YMMV.

 

[bgelectric]

The wiring from the contacts would be from an ats to the elevator controller.
The 120v feed is the power for the controller and the the 208 would be for the smoke fan.