A ___ switch is permitted to be used to control a 277-volt fluorescent lighting circuit.

A ___ switch is permitted to be used to control a 277-volt fluorescent lighting circuit.

• A. 120-277 V
• B. 120 V
• C. either a or b
• D. neither a nor b

Answer: (A)

The device must be rated for at least the circuit’s voltage. For a 277-volt fluorescent lighting circuit, a switch rated 120–277 V is permitted because it can safely interrupt voltages up to 277 V. A switch rated only for 120 V cannot be used on a 277 V circuit, since that would exceed its voltage rating and create a safety risk. (The current rating must also be suitable for the load, but the voltage rating is the key factor here.)

The device must be rated for at least the circuit’s voltage. For a 277-volt fluorescent lighting circuit, a switch rated 120–277 V is permitted because it can safely interrupt voltages up to 277 V. A switch rated only for 120 V cannot be used on a 277 V circuit, since that would exceed its voltage rating and create a safety risk. (The current rating must also be suitable for the load, but the voltage rating is the key factor here.)