Pick the right conductor for safety
Last month we looked at what it takes to safely power up a Class 2 or Class 3 control circuit. Now let¿s review the installation requirements to get that power to the load safely as well.
When CL2, CL3, CM, or MP conductors are installed without conduit, they must be supported from the building structure and installed in a neat and workmanlike manner. They may not simply be draped across ductwork, piping, and other above-ceiling construction, and they should not be hung in vertical runs without support. Article 725 states: ¿Access to equipment shall not be denied by an accumulation of conductors and cables that prevents removal of panels, including suspended ceiling panels.¿ With a single exception, low-voltage wiring may not be supported from or strapped to other conduit systems; Class 2 conductors, solely for the purpose of connection to the control circuits of a piece of equipment, may be supported from a conduit that carries the power supply conductors for that equipment. Circuits in elevator hoistways must be installed in metal conduit.