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NEC Table 430.248 & 430.250

Motor Full-Load Current Chart (NEC 430.248 & 430.250)

Single-phase and three-phase motor full-load current (FLC), straight from NEC Tables 430.248 and 430.250. Use these table values, not the nameplate, to size the branch circuit.

Quick answer: Motor full-load current comes from the NEC tables, not the nameplate. Single-phase (NEC 430.248): a 1 HP motor is 16A at 115V and 8A at 230V; a 5 HP is 28A at 230V. Three-phase (NEC 430.250): a 10 HP motor is 14A at 460V; a 50 HP is 65A at 460V. NEC 430.6(A)(1) requires you to size the branch-circuit conductors and breaker from these table values; the nameplate FLA is used only for the overload device (430.32).

Motor FLC Tables (NEC 430.248 & 430.250)

NEC Table 430.248 — single-phase motor full-load current (amperes). Source: NFPA 70 (NEC) 2023, Table 430.248.
HP115V208V230V
1/64.42.42.2
1/45.83.22.9
1/37.243.6
1/29.85.44.9
3/413.87.66.9
1168.88
1-1/2201110
22413.212
33418.717
55630.828
7-1/2804440
101005550
NEC Table 430.250 — three-phase motor full-load current (amperes), squirrel-cage and wound-rotor. Source: NFPA 70 (NEC) 2023, Table 430.250.
HP208V230V460V575V
1/22.42.21.10.9
3/43.53.21.61.3
14.64.22.11.7
1-1/26.6632.4
27.56.83.42.7
310.69.64.83.9
516.715.27.66.1
7-1/224.222119
1030.8281411
1546.2422117
2059.4542722
2574.8683427
3088804032
401141045241
501431306552
601691547762
752111929677
10027324812499
125343312156125
150396360180144
200528480240192

Full-load current in amperes. The three-phase 115V column exists only through 2 HP in NEC Table 430.250. These are the standard table values used for branch-circuit sizing; a design may use a higher listed motor current where marked, per NEC 430.6(A)(1).


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How to Size a Motor Branch Circuit

A motor circuit is sized differently from an ordinary load, and it turns on one rule that trips people up: you size the circuit from the NEC table full-load current, not the motor nameplate. NEC 430.6(A)(1) says the values in Tables 430.247 through 430.250 determine the conductor ampacity, the disconnect, and the branch-circuit short-circuit and ground-fault protective device. The nameplate full-load amps (FLA) is used only to size the running-overload device (430.6(A)(2) and 430.32).

From the table FLC, the branch circuit has two independent parts. The conductor is sized so its ampacity is at least 125% of the FLC (NEC 430.22). The short-circuit/ground-fault breaker may be sized up to 250% of the FLC for a standard inverse-time breaker (NEC 430.52 and Table 430.52), rounded up to the next standard size if needed to let the motor start (430.52(C)(1) Exception 1). That is why a motor circuit legally shows a small conductor under a large breaker: the conductor is protected from sustained overload by the separate overload device (430.32), and motor conductors are exempt from the 240.4(D) small-conductor limit via 240.4(G). The tables below apply these rules to the table FLC.

Motor Branch-Circuit Sizing (Conductor & Breaker)

Single-phase 230V motors: conductor at 125% FLC (75°C copper) and the maximum inverse-time breaker at 250% FLC. Per NEC 430.22 and 430.52.
HPFLC (A)Min. conductor (75°C Cu)Max. inverse-time breaker
1/62.2#1415A
1/42.9#1415A
1/33.6#1415A
1/24.9#1415A
3/46.9#1420A
18#1420A
1-1/210#1425A
212#1430A
317#1245A
528#1070A
7-1/240#8100A
1050#6125A
Three-phase 460V motors: conductor at 125% FLC (75°C copper) and the maximum inverse-time breaker at 250% FLC. Per NEC 430.22 and 430.52.
HPFLC (A)Min. conductor (75°C Cu)Max. inverse-time breaker
1/21.1#1415A
3/41.6#1415A
12.1#1415A
1-1/23#1415A
23.4#1415A
34.8#1415A
57.6#1420A
7-1/211#1430A
1014#1435A
1521#1060A
2027#1070A
2534#890A
3040#8100A
4052#6150A
5065#4175A
6077#3200A
7596#1250A
100124#2/0350A
125156#3/0400A
150180#4/0450A
200240350 kcmil600A

Conductor is the smallest 75°C copper wire whose Table 310.16 ampacity meets 125% of the FLC (valid for THHN/THWN-2 on 75°C terminals); NM-B cable is limited to the 60°C column. The breaker shown is the maximum permitted short-circuit/ground-fault device; a smaller standard size is used when the motor will start on it. Overload protection is separate and sized from the nameplate (430.32).


Worked Example

10 HP, 460V, three-phase motor

Table 430.250 FLC = 14A. Conductor = 14 × 1.25 = 17.5A. Breaker = 14 × 2.5 = 35A.

The conductor needs 17.5A of ampacity, so #14 copper (20A at 75°C) works. The maximum inverse-time breaker is 35A, which is a standard size. So the branch circuit is #14 copper on a 35A breaker, with the overload device set from the nameplate (about 125% of nameplate FLA). If you had (wrongly) sized from a nameplate reading of, say, 13A, you would get a different, non-code result. The table value governs.


Frequently Asked Questions

What is the full-load current of a 1 HP motor?

Per NEC Table 430.248, a single-phase 1 HP motor is 16A at 115V and 8A at 230V. Per NEC Table 430.250, a three-phase 1 HP motor is 4.2A at 230V, 2.1A at 460V, and 1.7A at 575V. Use these table values, not the nameplate amps, to size the branch-circuit conductors and the short-circuit/ground-fault breaker (NEC 430.6(A)(1)).

Do I use the nameplate amps or the NEC table to size a motor circuit?

Use the NEC table. NEC 430.6(A)(1) requires the values in Tables 430.247 through 430.250 to size the branch-circuit conductors, the ampacity, the disconnect, and the short-circuit/ground-fault protective device. The motor nameplate full-load amps (FLA) is used only to size the running-overload device, per 430.6(A)(2) and 430.32. This is the single most common motor-circuit mistake.

What size wire and breaker for a 10 HP three-phase motor at 460V?

A 10 HP, 460V, three-phase motor has a table full-load current of 14A (NEC Table 430.250). The branch-circuit conductor is sized at 125% of FLC = 17.5A, which is #14 copper at the 75°C column. The maximum inverse-time breaker is 250% of FLC = 35A (NEC 430.52, Table 430.52). So #14 copper on a 35A breaker, with the overload device set from the nameplate. The small #14 conductor under a 35A breaker is code-correct because motor conductors are exempt from the 240.4(D) small-conductor rule (240.4(G)); the overload device protects the wire, not the breaker.

Why is the motor breaker so much bigger than the wire ampacity?

A motor draws several times its running current for a moment at startup (locked-rotor / inrush). NEC 430.52 lets the branch-circuit short-circuit/ground-fault breaker be sized up to 250% of the full-load current (inverse-time type) so it does not trip on that inrush. The conductor is only sized to 125% of FLC (430.22) and is protected against sustained overload by the separate overload device (430.32), not by the branch breaker. That is why you see a small conductor under a large breaker on a motor circuit, and why motor conductors are exempt from the 240.4(D) small-conductor limit via 240.4(G).

What is the full-load current of a 5 HP single-phase motor at 230V?

Per NEC Table 430.248, a 5 HP single-phase motor at 230V has a full-load current of 28A (56A at 115V). Sized to 125%, the conductor ampacity is 35A, which is #10 copper at 75°C, and the maximum inverse-time breaker is 70A per NEC 430.52.

Are the NEC motor FLC tables the same in the 2017, 2020, and 2023 editions?

Yes. The full-load current values in NEC Tables 430.248 (single-phase) and 430.250 (three-phase) have not changed across the 2017, 2020, and 2023 editions of NFPA 70. The section numbers for the sizing rules (430.6, 430.22, 430.32, 430.52) are also unchanged.

How do I size motor overload protection?

Overload protection is sized from the motor nameplate full-load amps (FLA), not the NEC table. Per NEC 430.32(A)(1), a continuous-duty motor over 1 HP uses 125% of nameplate FLA when the motor has a marked service factor of 1.15 or higher, or a marked temperature rise of 40°C or less; otherwise 115%. This overload device, separate from the branch-circuit breaker, is what protects the motor and conductor from a sustained overload.


Related Calculators & Charts

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