Under the horsepower requirement rule, the motor nameplate must list horsepower when the motor is at least ___ hp.

• A. 2
• B. 1/8
• C. 1/2
• D. 1/4

Answer: (B)

Under this rule, the horsepower listed on a motor’s nameplate is required for motors that are 1/8 horsepower or larger. That threshold exists because once a motor reaches 1/8 hp, its electrical characteristics—such as starting current and running current—impact how you size fuses, breakers, and conductors, and how you verify safe operation with the supply. So the smallest motor size that triggers the nameplate horsepower requirement is 1/8 hp. Motors bigger than that must have the horsepower clearly listed; motors smaller than that are not covered by this specific requirement.