What is the minimum working space requirement for a circuit operating at 120V with exposed live parts?

For a circuit operating at 120V with exposed live parts, the National Electrical Code (NEC) specifies minimum working space requirements to ensure safety for individuals who may be working on or near electrical equipment. According to NEC Article 110.26, the minimum distance for working space in front of electrical equipment is determined by the voltage of the equipment and the conditions present.

In this case, the requirement for a circuit operating at 120V is that there should be at least 3 feet of working space in front of the panel or equipment where the exposed live parts are located. This distance allows enough room for personnel to work safely while minimizing the risk of accidental contact with the live parts.

Choosing 3 feet aligns with the NEC guidelines that aim to protect workers by providing sufficient distance to reduce potential hazards associated with electrical shock or arcing. The other options, such as 2 feet, 4 feet, and 5 feet do not meet the specifications outlined in the NEC for this specific voltage and scenario, making the correct answer clear.