Which equipment explicitly requires overcurrent protection?

Which equipment explicitly requires overcurrent protection?

• A. Motor-operated equipment and transformers
• B. Lighting fixtures
• C. Electrical outlets
• D. Terminal blocks

Answer: (A)

Overcurrent protection is required for equipment that can experience high fault or inrush currents and that the code specifically intends to protect. Motor-operated equipment and transformers are singled out because they can draw large starting currents and respond to faults with rapid heating of windings; the code requires protective devices sized to the motor or transformer rating to prevent damage or fire. For motors, this includes motor overload protection and appropriate short-circuit protection on the circuit feeding the motor. For transformers, primary protection (and sometimes secondary protection) is required to limit fault currents and protect the windings. The other items—lighting fixtures, electrical outlets, and terminal blocks—rely on the circuit’s overarching overcurrent protection rather than requiring a dedicated protective device built into the equipment itself, so they aren’t described as explicitly requiring overcurrent protection.

Overcurrent protection is required for equipment that can experience high fault or inrush currents and that the code specifically intends to protect. Motor-operated equipment and transformers are singled out because they can draw large starting currents and respond to faults with rapid heating of windings; the code requires protective devices sized to the motor or transformer rating to prevent damage or fire. For motors, this includes motor overload protection and appropriate short-circuit protection on the circuit feeding the motor. For transformers, primary protection (and sometimes secondary protection) is required to limit fault currents and protect the windings. The other items—lighting fixtures, electrical outlets, and terminal blocks—rely on the circuit’s overarching overcurrent protection rather than requiring a dedicated protective device built into the equipment itself, so they aren’t described as explicitly requiring overcurrent protection.