HOLT Electricians Practice Exam

The NEC requires motor branch circuit short-circuit and ground-fault protection to be sized not greater than what?

1. The names of the devices

2. Standard voltage ratings

3. The percentages listed in Table 430-52

4. Local code regulations

The correct answer is: The percentages listed in Table 430-52

The National Electrical Code (NEC) specifies that the short-circuit and ground-fault protection for motor branch circuits must be sized according to certain percentages outlined in Table 430-52. This table provides guidelines for determining the appropriate device ratings based on the full-load current of the motor. Adhering to these requirements is critical for ensuring the safety and protection of both the motor and the electrical system. The selected option reflects the NEC's intent to provide standardized and reliable guidelines that help prevent overcurrent conditions, which could lead to equipment damage or electrical fires. By limiting the size of the protection devices to those specified percentages, the code achieves a balance between adequate protection and operational efficiency for motors, ensuring they can start and operate under normal load without unnecessary tripping. Other options do not directly align with the requirements set forth by the NEC for this specific protection aspect, as they may refer to more general guidelines or external regulations rather than the precise standards established for motor protection.