1/2 hp motor: how many amps?
Full-load current from NEC Article 430 tables.
4.9 A
1/2 hp motor full-load current at 230 V single-phase · 0.37 kW output
Full-load current by voltage
| Supply | Full-load amps | Conductor ampacity (125%) |
|---|---|---|
| 115 V single-phase | 9.8 A | 12.2 A |
| 230 V single-phase | 4.9 A | 6.1 A |
| 208 V three-phase | 2.4 A | 3.0 A |
| 230 V three-phase | 2.2 A | 2.8 A |
| 460 V three-phase | 1.1 A | 1.4 A |
NEC 430.248/430.250 table values for typical induction motors; use these (not the nameplate) to size conductors and short-circuit protection, and the nameplate for overload protection.
FAQ
How many amps does a 1/2 hp motor draw?
Per NEC tables, 9.8 A A at 115 V single-phase; 4.9 A A at 230 V single-phase; 2.4 A A at 208 V three-phase; 2.2 A A at 230 V three-phase; 1.1 A A at 460 V three-phase.
How many watts is 1/2 hp?
1/2 hp = 373 W of mechanical output. Electrical input is higher because of motor efficiency and power factor.