The voltages listed below are standard rated motor voltages. This includes induction-type and synchronous-type three-phase alternating-current motors.

Full-Load Amps: Three-Phase
Alternating-Current Motors

Source: NFPA 70, National Electrical Code, Table 430.250
Induction-Type Squirrel Cage and Wound Rotor (Amperes) Synchronous-Type Unity Power Factor (Amperes)
HP 115 Volts 200 Volts 208 Volts 230 Volts 460 Volts 575 Volts 2300 Volts 230 Volts 460 Volts 575 Volts 2300 Volts
½ 4.4 2.5 2.4 2.2 1.1 0.9 -- -- -- -- --
¾ 6.4 3.7 3.5 3.2 1.6 1.3 -- -- -- -- --
1 8.4 4.8 4.6 4.2 2.1 1.7 -- -- -- -- --
12 6.9 6.6 6 3 2.4 -- -- -- -- --
2 13.6 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 -- -- -- -- --
-- 25.3 24.2 22 11 9 -- -- -- -- --
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 -- 53 26 21 --
30 -- 92 88 80 40 32 -- 63 32 26 --
40 -- 120 114 104 52 41 -- 83 41 33 --
50 -- 150 143 130 65 52 -- 104 52 42 --
60 -- 177 169 154 77 62 16 123 61 49 12
75 -- 221 211 192 96 77 20 155 78 62 15
100 -- 285 273 248 124 99 26 202 101 81 20
125 -- 359 343 312 156 125 31 253 126 101 25
150 -- 414 396 360 180 144 37 302 151 121 30
200 -- 552 528 480 240 192 49 400 201 161 40
125 -- 359 343 312 156 125 31 253 126 101 25
150 -- 414 396 360 180 144 37 302 151 121 30
200 -- 552 528 480 240 192 49 400 201 161 40
400 -- -- -- -- 477 382 95 -- -- -- --
450 -- -- -- -- 515 412 103 -- -- -- --
500 -- -- -- -- 590 472 118 -- -- -- --

Note: For synchronous-type motors with 0.9 and 0.8 power factor, there amperes listed in the table should be multiplied by a factor of 1.1 and 1.25, respectively.

Motor Wire Sizing

It is required by the NEC for circuits supplying single motors to have an ampacity rating of greater than or equal to 125% of the full-load ampacity rating of the motor. Branch circuits that contain two or more motors must have wire in which the ampacity rating of the wire must be at least 125% of the full-load current of the largest motor, plus the sum of full-load currents for the rest of the motors. For example, if there are three 15-amp motors in the circuit, the ampacity rating of the wire feeding the circuit must exceed 15 + 15 + (15 * 1.25) = 48.75 Amps. There are exceptions to this requirement, which would include interlocks of two or more motors to prevent them from running at the same time. Typically, the nominal system voltage for a motor will be above the nameplate voltage to compensate for any voltage drop in the circuit.

Motor Nameplate Voltages versus Nominal System Voltages
Motor Nameplate Voltage
Nominal System Voltage
115 120
230 240
460 480
575 600
4,000 4,160
6,600 6,900
13,200 13,800

For more details into sizing wire and circuit protection devices for motors, view the Motor Wire Size and Circuit Protection Chart and the Motor Wire Size Calculator.

View wire size charts from the list below.


Visit the Terms of Use and Privacy Policy for this site. Your feedback is greatly appreciated. Let us know how we can improve.