NEC Table 430.249 — Two-Phase AC Motors (4-Wire) Full-Load Current
Two-phase, 4-wire induction motors. Rare today; current in the common conductor of a 3-wire system is 1.41 times the value shown.
A 10 HP two-phase motor draws 12 A at 460 V, and a 125 HP motor draws 108 A at 575 V. Use these values, not the nameplate, to size conductors and short-circuit protection.
- Three-Phase AC Motors (430.250)
- Single-Phase AC Motors (430.248)
- Direct-Current Motors (430.247)
- Two-Phase AC Motors (4-Wire) (430.249)
| Horsepower | 115 V | 230 V | 460 V | 575 V | 2300 V |
|---|---|---|---|---|---|
| 1/2 HP | 4 | 2 | 1 | 0.8 | — |
| 3/4 HP | 4.8 | 2.4 | 1.2 | 1 | — |
| 1 HP | 6.4 | 3.2 | 1.6 | 1.3 | — |
| 1 1/2 HP | 9 | 4.5 | 2.3 | 1.8 | — |
| 2 HP | 11.8 | 5.9 | 3 | 2.4 | — |
| 3 HP | — | 8.3 | 4.2 | 3.3 | — |
| 5 HP | — | 13.2 | 6.6 | 5.3 | — |
| 7 1/2 HP | — | 19 | 9 | 8 | — |
| 10 HP | — | 24 | 12 | 10 | — |
| 15 HP | — | 36 | 18 | 14 | — |
| 20 HP | — | 47 | 23 | 19 | — |
| 25 HP | — | 59 | 29 | 24 | — |
| 30 HP | — | 69 | 35 | 28 | — |
| 40 HP | — | 90 | 45 | 36 | — |
| 50 HP | — | 113 | 56 | 45 | — |
| 60 HP | — | 133 | 67 | 53 | 14 |
| 75 HP | — | 166 | 83 | 66 | 18 |
| 100 HP | — | 218 | 109 | 87 | 23 |
| 125 HP | — | 270 | 135 | 108 | 28 |
| 150 HP | — | 312 | 156 | 125 | 32 |
| 200 HP | — | 416 | 208 | 167 | 43 |
Frequently asked questions
How many amps does a 10 HP two-phase ac motor draw?
A 10 HP two-phase motor draws 12 A at 460 V. 24 A at 230 V, 12 A at 460 V, 10 A at 575 V.
Should I use the nameplate amps or the table amps?
Use the table full-load current for sizing branch-circuit conductors, the short-circuit and ground-fault protective device, and the disconnect (430.6(A)(1)). Use the motor nameplate current only for sizing the separate overload protection.
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