Motor Circuit Data Chart

One row per motor: table full-load current, minimum 75°C copper conductor (at 125% of FLC), maximum dual-element fuse and inverse-time breaker (175% and 250%, rounded up per Exception 1), NEMA starter size, and minimum disconnect switch (115% of FLC) — the complete NEC 430 stack for three-phase squirrel-cage motors at 208, 230, 460, and 575 V. Every column derives from the same verified tables behind our FLA, ampacity, and starter charts, so this page and those pages cannot disagree.

460 V three-phase

The workhorse industrial voltage.

NEC 430

Three-phase squirrel-cage motors at 460 V: table FLC (430.250), minimum conductor ampacity (125% FLC) with the smallest 75°C copper pick, maximum dual-element time-delay fuse (175%) and inverse-time breaker (250%) rounded up to standard sizes, NEMA starter size, and minimum standard disconnect (115% FLC). Fuse and breaker columns are code MAXIMUMS, not recommendations.
HP	FLC (A)	Min. ampacity (125%)	Copper wire (75°C)	Max TD fuse (A)	Max breaker (A)	NEMA starter	Disconnect (A)
1/2	1.1	1.38	14 AWG	15	15	00	30
3/4	1.6	2	14 AWG	15	15	00	30
1	2.1	2.63	14 AWG	15	15	00	30
1.5	3	3.75	14 AWG	15	15	00	30
2	3.4	4.25	14 AWG	15	15	00	30
3	4.8	6	14 AWG	15	15	0	30
5	7.6	9.5	14 AWG	15	20	0	30
7.5	11	13.75	14 AWG	20	30	1	30
10	14	17.5	14 AWG	25	35	1	30
15	21	26.25	10 AWG	40	60	2	30
20	27	33.75	10 AWG	50	70	2	60
25	34	42.5	8 AWG	60	90	2	60
30	40	50	8 AWG	70	100	3	60
40	52	65	6 AWG	100	150	3	60
50	65	81.25	4 AWG	125	175	3	100
60	77	96.25	3 AWG	150	200	4	100
75	96	120	1 AWG	175	250	4	200
100	124	155	2/0 AWG	225	350	4	200
125	156	195	3/0 AWG	300	400	5	200
150	180	225	4/0 AWG	350	450	5	400
200	240	300	350 kcmil	450	600	5	400
250	302	377.5	500 kcmil	600	800	6	400
300	361	451.25	2 × 4/0 AWG	700	1000	6	600
350	414	517.5	2 × 300 kcmil	800	1200	6	600
400	477	596.25	2 × 350 kcmil	1000	1200	6	600
450	515	643.75	2 × 400 kcmil	1000	1600	7	600
500	590	737.5	2 × 500 kcmil	1200	1600	7	800

Wire sizes assume 75°C copper terminations (the motor-gear norm), three current-carrying conductors, 30°C ambient — derate for heat, conduit fill, or long runs (the voltage-drop calculator covers the last). Parallel entries (2 × 500 kcmil) are equal sets per phase, 1/0 AWG minimum each, per 310.10(G).

230 V three-phase

Small-shop and legacy 240 V systems.

NEC 430

Three-phase squirrel-cage motors at 230 V: table FLC (430.250), minimum conductor ampacity (125% FLC) with the smallest 75°C copper pick, maximum dual-element time-delay fuse (175%) and inverse-time breaker (250%) rounded up to standard sizes, NEMA starter size, and minimum standard disconnect (115% FLC). Fuse and breaker columns are code MAXIMUMS, not recommendations.
HP	FLC (A)	Min. ampacity (125%)	Copper wire (75°C)	Max TD fuse (A)	Max breaker (A)	NEMA starter	Disconnect (A)
1/2	2.2	2.75	14 AWG	15	15	00	30
3/4	3.2	4	14 AWG	15	15	00	30
1	4.2	5.25	14 AWG	15	15	00	30
1.5	6	7.5	14 AWG	15	15	00	30
2	6.8	8.5	14 AWG	15	20	0	30
3	9.6	12	14 AWG	20	25	0	30
5	15.2	19	14 AWG	30	40	1	30
7.5	22	27.5	10 AWG	40	60	1	30
10	28	35	10 AWG	50	70	2	60
15	42	52.5	6 AWG	80	110	2	60
20	54	67.5	4 AWG	100	150	3	100
25	68	85	4 AWG	125	175	3	100
30	80	100	3 AWG	150	200	3	100
40	104	130	1 AWG	200	300	4	200
50	130	162.5	2/0 AWG	250	350	4	200
60	154	192.5	3/0 AWG	300	400	5	200
75	192	240	250 kcmil	350	500	5	400
100	248	310	350 kcmil	450	700	5	400
125	312	390	600 kcmil	600	800	6	400
150	360	450	2 × 4/0 AWG	700	1000	6	600
200	480	600	2 × 350 kcmil	1000	1200	6	600

208 V three-phase

Wye systems fed from 120/208 V services; starters use the NEMA 200 V column.

NEC 430

Three-phase squirrel-cage motors at 208 V: table FLC (430.250), minimum conductor ampacity (125% FLC) with the smallest 75°C copper pick, maximum dual-element time-delay fuse (175%) and inverse-time breaker (250%) rounded up to standard sizes, NEMA starter size, and minimum standard disconnect (115% FLC). Fuse and breaker columns are code MAXIMUMS, not recommendations.
HP	FLC (A)	Min. ampacity (125%)	Copper wire (75°C)	Max TD fuse (A)	Max breaker (A)	NEMA starter	Disconnect (A)
1/2	2.4	3	14 AWG	15	15	00	30
3/4	3.5	4.38	14 AWG	15	15	00	30
1	4.6	5.75	14 AWG	15	15	00	30
1.5	6.6	8.25	14 AWG	15	20	00	30
2	7.5	9.38	14 AWG	15	20	0	30
3	10.6	13.25	14 AWG	20	30	0	30
5	16.7	20.88	12 AWG	30	45	1	30
7.5	24.2	30.25	10 AWG	45	70	1	30
10	30.8	38.5	8 AWG	60	80	2	60
15	46.2	57.75	6 AWG	90	125	3	60
20	59.4	74.25	4 AWG	110	150	3	100
25	74.8	93.5	3 AWG	150	200	3	100
30	88	110	2 AWG	175	225	4	200
40	114	142.5	1/0 AWG	200	300	4	200
50	143	178.75	3/0 AWG	300	400	5	200
60	169	211.25	4/0 AWG	300	450	5	200
75	211	263.75	300 kcmil	400	600	5	400
100	273	341.25	500 kcmil	500	700	6	400
125	343	428.75	2 × 4/0 AWG	700	1000	6	400
150	396	495	2 × 250 kcmil	700	1000	6	600
200	528	660	2 × 400 kcmil	1000	1600	—	800

575 V three-phase

Canadian and mining supply; starter sizes match 460 V (ICS 2 rates them together).

NEC 430

Three-phase squirrel-cage motors at 575 V: table FLC (430.250), minimum conductor ampacity (125% FLC) with the smallest 75°C copper pick, maximum dual-element time-delay fuse (175%) and inverse-time breaker (250%) rounded up to standard sizes, NEMA starter size, and minimum standard disconnect (115% FLC). Fuse and breaker columns are code MAXIMUMS, not recommendations.
HP	FLC (A)	Min. ampacity (125%)	Copper wire (75°C)	Max TD fuse (A)	Max breaker (A)	NEMA starter	Disconnect (A)
1/2	0.9	1.13	14 AWG	15	15	00	30
3/4	1.3	1.63	14 AWG	15	15	00	30
1	1.7	2.13	14 AWG	15	15	00	30
1.5	2.4	3	14 AWG	15	15	00	30
2	2.7	3.38	14 AWG	15	15	00	30
3	3.9	4.88	14 AWG	15	15	0	30
5	6.1	7.63	14 AWG	15	20	0	30
7.5	9	11.25	14 AWG	20	25	1	30
10	11	13.75	14 AWG	20	30	1	30
15	17	21.25	12 AWG	30	45	2	30
20	22	27.5	10 AWG	40	60	2	30
25	27	33.75	10 AWG	50	70	2	60
30	32	40	8 AWG	60	80	3	60
40	41	51.25	6 AWG	80	110	3	60
50	52	65	6 AWG	100	150	3	60
60	62	77.5	4 AWG	110	175	4	100
75	77	96.25	3 AWG	150	200	4	100
100	99	123.75	1 AWG	175	250	4	200
125	125	156.25	2/0 AWG	225	350	5	200
150	144	180	3/0 AWG	300	400	5	200
200	192	240	250 kcmil	350	500	5	400
250	242	302.5	350 kcmil	450	700	6	400
300	289	361.25	500 kcmil	600	800	6	400
350	336	420	600 kcmil	600	1000	6	400
400	382	477.5	2 × 250 kcmil	700	1000	6	600
450	412	515	2 × 300 kcmil	800	1200	7	600
500	472	590	2 × 350 kcmil	1000	1200	7	600

How this chart is built

Every column is computed, not transcribed: full-load currents from NEC Table 430.250 (the motor FLA chart), conductor picks from Table 310.16 (the ampacity chart), protection percentages from Table 430.52(C)(1) (the motor circuit protection chart), starter sizes from NEMA ICS 2 (the NEMA starter size chart), and disconnect sizes from the 115% rule against the standard switch ladder (the safety switch ratings chart). Overload protection is deliberately absent — it sizes from the NAMEPLATE current of the specific motor you install, at 115–125% per 430.32, and no table keyed to horsepower can print it honestly.

Common questions

What wire size do I need for a 30 HP, 460 V motor?

The table full-load current is 40 A; conductors size at 125% of that (430.22), so 50 A minimum ampacity — 8 AWG copper at 75°C. Protection: up to a 70 A time-delay fuse or 100 A inverse-time breaker (430.52 with the round-up allowance), a NEMA Size 3 starter, and a 60 A disconnect (115% of FLC). One row of the 460 V table below.

Why is the breaker bigger than the wire ampacity in this chart?

Because motor branch-circuit devices only protect against short circuits and ground faults — they must be large enough to ride the starting inrush. The conductors are protected from overload by the starter’s overload relay at 115–125% of nameplate current, not by the breaker. This split is the whole design of NEC Article 430, and it is why a 10 AWG wire legally lives behind an 80 A breaker in a motor circuit.

Are the fuse and breaker columns requirements or maximums?

Maximums. The chart prints the largest permitted dual-element time-delay fuse (175% of FLC) and inverse-time breaker (250%), each rounded up to the next standard size as Exception 1 allows. Smaller devices are always permitted if they hold the starting current — many engineers spec the fuse at 125–150% for closer protection.

What do the dashes in the starter column mean?

The FLA tables publish motors beyond the NEMA ladder at that voltage — a 200 HP motor at 208 V exceeds Size 6, the largest starter with a 200 V rating. Those motors get engineered starters, solid-state soft starters, or VFDs rather than a catalog NEMA frame.

Can I use this chart for single-phase motors?

No — these tables derive from the three-phase FLC table (430.250). Single-phase full-load currents are far higher per horsepower; get them from the motor FLA chart and run the same percentages: 125% for wire, 175%/250% for protection, 115% for the disconnect.

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