Motor Data
Full-load current tables, branch circuit sizing, OCPD sizing, and NEMA starter sizes.
6 reference items · 4 sections
Single-Phase Motor FLC
Single-Phase AC Motor Full-Load Current
| HP | 115V | 200V | 208V | 230V |
|---|---|---|---|---|
| 1/6 | 4.4 | 2.5 | 2.4 | 2.2 |
| 1/4 | 5.8 | 3.3 | 3.2 | 2.9 |
| 1/3 | 7.2 | 4.1 | 4.0 | 3.6 |
| 1/2 | 9.8 | 5.6 | 5.4 | 4.9 |
| 3/4 | 13.8 | 7.9 | 7.6 | 6.9 |
| 1 | 16 | 9.2 | 8.8 | 8.0 |
| 1½ | 20 | 11.5 | 11.0 | 10 |
| 2 | 24 | 13.8 | 13.2 | 12 |
| 3 | 34 | 19.6 | 18.7 | 17 |
| 5 | 56 | 32.2 | 30.8 | 28 |
| 7½ | 80 | 46.0 | 44.0 | 40 |
| 10 | 100 | 57.5 | 55.0 | 50 |
1.Use these values (not motor nameplate) for sizing branch circuit components
2.For motor starting, multiply FLC by 6-8× for locked rotor current estimate
Three-Phase Motor FLC
Three-Phase AC Motor Full-Load Current
| HP | 208V | 230V | 460V | 575V |
|---|---|---|---|---|
| ½ | 2.4 | 2.2 | 1.1 | 0.9 |
| ¾ | 3.5 | 3.2 | 1.6 | 1.3 |
| 1 | 4.6 | 4.2 | 2.1 | 1.7 |
| 1½ | 6.6 | 6.0 | 3.0 | 2.4 |
| 2 | 7.5 | 6.8 | 3.4 | 2.7 |
| 3 | 10.6 | 9.6 | 4.8 | 3.9 |
| 5 | 16.7 | 15.2 | 7.6 | 6.1 |
| 7½ | 24.2 | 22 | 11 | 9.0 |
| 10 | 30.8 | 28 | 14 | 11 |
| 15 | 46.2 | 42 | 21 | 17 |
| 20 | 59.4 | 54 | 27 | 22 |
| 25 | 74.8 | 68 | 34 | 27 |
| 30 | 88 | 80 | 40 | 32 |
| 40 | 114 | 104 | 52 | 41 |
| 50 | 143 | 130 | 65 | 52 |
| 60 | 169 | 154 | 77 | 62 |
| 75 | 211 | 192 | 96 | 77 |
| 100 | 273 | 248 | 124 | 99 |
| 125 | 343 | 312 | 156 | 125 |
| 150 | 396 | 360 | 180 | 144 |
| 200 | 528 | 480 | 240 | 192 |
1.Values from NEC Table 430.250
2.For 200V: multiply 208V values by 1.0 (use 208V column)
3.For dual-voltage motors, use the voltage at which motor is connected
Motor Branch Circuit Sizing
Motor Circuit Conductor Sizing
| Variable | Description | Unit |
|---|---|---|
| FLC | Full-load current from table | Amperes |
| 125% | Safety factor for continuous duty | multiplier |
Motor Overcurrent Protection (OCPD) Sizing
| Protection Type | Max % of FLC |
|---|---|
| Non-time delay fuse | 300% |
| Dual-element (time-delay) fuse | 175% |
| Instantaneous trip breaker | 800% |
| Inverse time breaker | 250% |
1.If calculated value doesn't match standard size, round UP to next standard size
2.Exception: If next standard size still causes nuisance tripping, may increase per 430.52(C)(1)(b)
Standard Breaker/Fuse Sizes
Motor Overload Protection
| Motor Service Factor | Max Overload % |
|---|---|
| SF ≥ 1.15 | 125% of nameplate FLA |
| SF < 1.15 | 115% of nameplate FLA |
| Temperature rise ≤ 40°C | 125% of nameplate FLA |
| Temperature rise > 40°C | 115% of nameplate FLA |
1.Overload protection uses NAMEPLATE current (not table FLC)
2.This is different from branch circuit protection which uses table FLC
Motor Starter (Controller) Sizing
NEMA Motor Starter Sizes
| NEMA Size | Max HP (1Φ 230V) | Max HP (3Φ 230V) | Max HP (3Φ 460V) | Max Amps |
|---|---|---|---|---|
| 00 | 1 | 1½ | 2 | 9 |
| 0 | 2 | 3 | 5 | 18 |
| 1 | 3 | 7½ | 10 | 27 |
| 2 | 7½ | 15 | 25 | 45 |
| 3 | — | 30 | 50 | 90 |
| 4 | — | 50 | 100 | 135 |
| 5 | — | 100 | 200 | 270 |
| 6 | — | 200 | 400 | 540 |
| 7 | — | 300 | 600 | 810 |
1.NEMA starters sized by HP and voltage
2.— = not applicable for this voltage/phase combination
Take It With You
Access quick reference, 8,000+ practice questions, and NEC calculators anywhere with the NEC Mastery app.
