I often see instrumentation circuits (24 VDC, 4-20 mA transmitters) installed using 300V shielded pair cable (#18AWG and smaller, Type CM or similar). These circuits are often fed from power supplies that are not listed/labelled as class 2.
My understanding is that 725.27 would require these cables to be Class 1 circuits, with 600V insulation. Otherwise, they would need to be installed per Chapter 3, and would need to be minimum #14 AWG. Am I missing something somewhere else in the code which permits this type of installation? Because we come across it often.
Thanks
My understanding is that 725.27 would require these cables to be Class 1 circuits, with 600V insulation. Otherwise, they would need to be installed per Chapter 3, and would need to be minimum #14 AWG. Am I missing something somewhere else in the code which permits this type of installation? Because we come across it often.
Thanks