Mixed voltages in a conduit

[BillH]

replying to hrhofmann, BillH wrote: Low voltage wires for control circuits are typically twisted pair, which gives significant protection from picking up signals from other wires running parallel. Using a 14 gauge power cable in this scenario could result in the

60 cycle power lines inducing voltage at 60 cycles into the low voltage control wires.

[gfretwell]

You are never going to induce enough voltage to pick a relay and that would usually be what is at the end of an unshielded or untwisted pair. Any electronic circuit should be designed to reject incidental

60 hz noise. The real issue with class 2 and 3 wires in conduits is safety, isolation and how they get terminated. As a general rule you will not see them in the same conduit as mains voltages because of those rules in the code even if both are cable type wiring methods that meet the isolation requirement. Then the issue is termination. If it is class 1 low voltage, they are treated just like mains voltages.