Electrical
Three-Phase Motor Full-Load Current
Full-load current for three-phase induction motors by horsepower and voltage, used for sizing conductors and overcurrent devices.
Source of these values
Values as commonly published for NFPA 70 Table 430.250, for three-phase alternating current motors at usual speeds and normal torque. Verify against your adopted edition.
| HP | 200 V | 208 V | 230 V | 460 V | 575 V |
|---|---|---|---|---|---|
| 1 | 4.8 | 4.6 | 4.2 | 2.1 | 1.7 |
| 2 | 7.8 | 7.5 | 6.8 | 3.4 | 2.7 |
| 3 | 11 | 10.6 | 9.6 | 4.8 | 3.9 |
| 5 | 17.5 | 16.7 | 15.2 | 7.6 | 6.1 |
| 10 | 32.2 | 30.8 | 28 | 14 | 11 |
| 15 | 48.3 | 46.2 | 42 | 21 | 17 |
| 20 | 62.1 | 59.4 | 54 | 27 | 22 |
| 25 | 78.2 | 74.8 | 68 | 34 | 27 |
| 30 | 92 | 88 | 80 | 40 | 32 |
| 40 | 120 | 114 | 104 | 52 | 41 |
| 50 | 150 | 143 | 130 | 65 | 52 |
| 60 | 177 | 169 | 154 | 77 | 62 |
| 75 | 221 | 211 | 192 | 96 | 77 |
| 100 | 285 | 273 | 248 | 124 | 99 |
| 125 | 359 | 343 | 312 | 156 | 125 |
| 150 | 414 | 396 | 360 | 180 | 144 |
| 200 | 552 | 528 | 480 | 240 | 192 |
| 0.5 | 2.5 | 2.4 | 2.2 | 1.1 | 0.9 |
| 0.75 | 3.7 | 3.5 | 3.2 | 1.6 | 1.3 |
| 1.5 | 6.9 | 6.6 | 6 | 3 | 2.4 |
| 7.5 | 25.3 | 24.2 | 22 | 11 | 9 |
In short
The code requires conductors and overcurrent devices for a motor circuit to be sized from a standard table value rather than the motor nameplate. At 460 volts, a 10 horsepower motor is 14 amperes, 25 horsepower is 34 amperes, and 100 horsepower is 124 amperes. Overload protection is the exception and uses the nameplate current.
Notes and limits
- These values are used for conductor and overcurrent device sizing. Overload protection is sized from the motor nameplate instead.
- Values are for squirrel-cage and wound-rotor induction motors at usual speeds and normal torque characteristics. Synchronous motors and direct-current motors have separate tables.
- For a motor voltage between the listed columns, the code directs you to use the nearest listed voltage.
Direct contact
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