NEC Commercial Electrical Practice Test

Which appliance is allowed to use a branch-circuit device as a disconnecting means?

1. Permanently connected motor

2. Portable heater

3. Permanently connected appliance rated over 1/8 horsepower

4. Permanently connected appliance rated at 1/8 horsepower or less

The correct answer is: Permanently connected appliance rated at 1/8 horsepower or less

The correct answer pertains to the NEC (National Electrical Code) regulations that distinguish between different types of appliances and their requirements for disconnecting means. A permanently connected appliance rated at 1/8 horsepower or less is permitted to use a branch-circuit device, such as a circuit breaker or switch, as its disconnecting means. This flexibility is provided because these lower-rated appliances typically do not draw significant current, making the use of a simple branch-circuit device adequate for safely disconnecting the power when necessary, such as for maintenance or in the event of an emergency. In contrast, appliances with higher ratings, such as those over 1/8 horsepower or permanently connected motors, require a more robust disconnecting means. These typically need a separate disconnect switch or a panel that can handle the higher load safely, ensuring compliance with electrical safety standards and reducing the risk of hazards. Therefore, the regulation acknowledges that higher power ratings necessitate more stringent disconnection requirements to ensure safety.