NEC Commercial Electrical Practice Test

Over what maximum voltage should circuit breakers used as switches in fluorescent lighting circuits be rated?

1. 120 volt

2. 240 volt

3. 277 volt

4. 480 volt

The correct answer is: 120 volt

In fluorescent lighting circuits, the maximum voltage rating for circuit breakers used as switches is typically 120 volts. This is due to the common use of 120-volt circuits in residential and light commercial applications for general lighting. The National Electrical Code (NEC) emphasizes safety and efficiency, and circuit breakers in these settings need to be compatible with the voltage levels of the lighting systems they control. While fluorescent lighting can operate at higher voltages, especially in commercial and industrial settings where 277-volt and 480-volt systems are sometimes found, the circuit breakers used as switches are designed for the most common residential and low-voltage commercial use, which is 120 volts. This ensures that the circuit breakers can safely interrupt the circuit without risk of failure or hazards at commonly used voltage levels. The other voltage options, while relevant in specific applications, concern higher voltage systems that typically require different types of circuit breakers designed for those levels instead of standard switches for fluorescent lighting.