Three-Phase Motor Full-Load Current Table (NEC 430.250)

NEC Table 430.250 • Three-Phase Motors

Three-Phase Motor Full-Load Current Table (NEC 430.250)

This table lists the full-load current (FLC) of three-phase induction motors from NEC Table 430.250, in amperes, for the standard US voltages. The NEC requires these table values (not the nameplate) to size motor branch-circuit conductors and short-circuit protection, while the nameplate current is used for the overload relay.

HP	kW (approx.)	200 V (A)	208 V (A)	230 V (A)	460 V (A)	575 V (A)
0.5	0.37	2.5	2.4	2.2	1.1	0.9
0.75	0.56	3.7	3.5	3.2	1.6	1.3
1	0.75	4.8	4.6	4.2	2.1	1.7
1.5	1.1	6.9	6.6	6	3	2.4
2	1.5	7.8	7.5	6.8	3.4	2.7
3	2.2	11	10.6	9.6	4.8	3.9
5	3.7	17.5	16.7	15.2	7.6	6.1
7.5	5.6	25.3	24.2	22	11	9
10	7.5	32.2	30.8	28	14	11
15	11.2	48.3	46.2	42	21	17
20	14.9	62.1	59.4	54	27	22
25	18.6	78.2	74.8	68	34	27
30	22.4	92	88	80	40	32
40	29.8	120	114	104	52	41
50	37.3	150	143	130	65	52
60	44.8	177	169	154	77	62
75	56.0	221	211	192	96	77
100	74.6	285	273	248	124	99
125	93.2	359	343	312	156	125
150	111.9	414	396	360	180	144
200	149.2	552	528	480	240	192

Values are for typical 1,750 rpm (4-pole) induction motors running at normal speed with normal torque characteristics. Motors built for especially low speeds, high torque or multi-speed operation can draw more current, so use the nameplate for those. The kW column is HP × 0.746 for reference only.

How the table is used

Conductors: at least 125% of the table FLC (NEC 430.22). Short-circuit protection: an inverse-time breaker is limited to 250% of FLC, a dual-element time-delay fuse to 175% and a non-time-delay fuse to 300% (Table 430.52), with a rounding-up allowance if the motor will not start. Overload relay: about 125% of the nameplate current for motors with a service factor of 1.15 or more, and 115% for others (430.32).

Worked example: a 10 HP, 460 V, three-phase motor

1. Table 430.250: FLC = 14 A.
2. Conductor ampacity: 14 × 1.25 = 17.5 A minimum.
3. Maximum inverse-time breaker: 14 × 2.5 = 35 A.
4. Overload relay: if the nameplate says 13 A and the service factor is 1.15, set it to about 13 × 1.25 = 16.3 A.
The motor branch-circuit calculator does the complete sizing, including wire and disconnect.

Using it for a 400 V, 50 Hz motor

NEC 430.250 covers 460 V, not 400 V. For motors outside North America, take the current from the nameplate, or estimate it from the power: I = kW × 1000 ÷ (√3 × 400 × PF × η). As a rough guide, a typical four-pole induction motor on 400 V draws about 1.8 to 2 A per kW of shaft power at full load. For example, a 7.5 kW motor with an efficiency of 0.88 and a power factor of 0.85 draws 7,500 ÷ (1.732 × 400 × 0.85 × 0.88) = 14.5 A. Real motors vary by manufacturer, so the nameplate always wins.

Common mistakes

Sizing the cable from the nameplate. The code table value is used for conductors and short-circuit protection; the nameplate is for the overload relay.
Forgetting the starting current. Across-the-line starting draws about 5 to 8 times FLC for a short time. Breaker and wire sizing rules already allow for it, but the supply must be able to handle it.
Using the 460 V column on a 400 V supply. The current is higher on a lower voltage for the same power.
Ignoring voltage drop. A long run to a motor can drop enough voltage to cause hard starting. Check it with the voltage drop quick table.

Frequently asked questions

What is the full-load current of a 10 HP motor? From NEC Table 430.250, a three-phase 10 HP motor is 28 A at 230 V, 14 A at 460 V and 11 A at 575 V.

Do I use the nameplate or the table to size the wire? Use the table value for the conductors and short-circuit protection (NEC 430.6). Use the nameplate current for the overload protection.

How do I find motor current at 400 V? Use the nameplate. If you only have the power, use I = kW × 1000 ÷ (√3 × 400 × PF × efficiency), or about 1.8 to 2 A per kW as a rough guide.

Safety note. These figures are reference values and not a substitute for your local electrical code or a qualified electrician.