What minimum size NM Cable Romex® is required for installation to the designated unit?

The minimum size NM Cable Romex® that is required for installation to a designated unit depends on several factors, including the circuit's amperage, the type of load being served, and the National Electrical Code (NEC) requirements pertaining to wire sizing.

In many residential applications, 10 AWG NM cable has a standard amperage capacity of 30 amps, making it suitable for circuits associated with certain appliances and equipment that require higher current. This size provides a margin of safety by being capable of handling higher loads without overheating.

If the designated unit in question is one that draws significant power, such as a large air conditioning unit or heavy machinery, using 10 AWG cable ensures compliance with codes designed to prevent electrical fires and other hazards associated with electrical installations.

Other sizes listed, like 8 AWG, 12 AWG, and 6 AWG, may serve specific applications, but they may either exceed the requirements for typical residential circuits (in the case of 6 and 8 AWG) or be under-rated for higher amperages (in the case of 12 AWG). Thus, the 10 AWG cable strikes a necessary balance between sufficient current-carrying capacity and appropriate sizing for the load mentioned.