In a 480/277-volt, 3Ø, 4-W panel, which wire color is permitted by the NEC® for a wire connected to breaker 41?

In a 480/277-volt, 3-phase, 4-wire system, the National Electrical Code (NEC) provides specific guidelines on wire color designations. In this context, the "C" option indicates that the wire used for a specific breaker, in this case, breaker 41, can be any of the designated colors for phase conductors, which typically include black, red, or blue.

In a three-phase system, it is standard practice to use specific colors for phase wires: black for one phase, red for another phase, and blue for the third. The color green is typically reserved for ground wires in electrical systems and does not serve as a phase or hot conductor. Therefore, because breaker 41 is accommodating the phases in a multi-phase system, using any of the defined colors that represent those phases is appropriate.

The mention of colors "I or II or III" implies a selection of suitable options depending on the wire's phase connection for proper circuit identification and is why this answer is permissible and correct in this context. This flexibility provides electricians with options while ensuring they adhere to color standards laid out by the NEC, thus facilitating clear identification and safety in wiring installations.