NEC Commercial Electrical Practice Test

For permanently connected appliances rated at not over what horsepower can the branch-circuit over-current device also serve as the disconnecting means?

1. 1/4 horsepower

2. 1/2 horsepower

3. 1 horsepower

4. 1/8 horsepower

The correct answer is: 1/8 horsepower

The correct choice indicates that the branch-circuit over-current device can serve as the disconnecting means for permanently connected appliances rated at not over 1/8 horsepower. In the context of the National Electrical Code (NEC), for appliances that are permanently connected and do not have a separate disconnecting means, the over-current device can fulfill this role only up to the specified horsepower limit. This regulation is in place to ensure both safety and convenience. If an appliance exceeds this horsepower rating, the potential for hazardous conditions increases, necessitating a separate disconnecting means for control of the appliance. The 1/8 horsepower limit is derived from performance and safety considerations, ensuring that the devices involved can adequately manage the electrical demand and prevent overload scenarios. This distinction is crucial in commercial electrical practice, as it informs electricians about how to wire appliances safely and in compliance with the NEC, thus reducing the risk of electrical fires and ensuring that maintenance can be performed safely.