NEMA (National Electrical Manufacturers Association) contactors and motor starters are rated by sizes. These sizes are grouped by rated current and power.
| NEMA size | Max. continuous amperes | Max. HP at 200 V, AC | Max. HP at 230 V, AC | Max. HP at 480/575 V, AC |
|---|---|---|---|---|
| 00 | 9 | 1.5 | 1.5 | 2 |
| 0 | 18 | 3 | 3 | 5 |
| 1 | 27 | 7.5 | 7.5 | 10 |
| 2 | 45 | 10 | 15 | 25 |
| 3 | 90 | 25 | 35 | 50 |
| 4 | 135 | 40 | 50 | 100 |
| 5 | 270 | 75 | 100 | 200 |
| 6 | 540 | 150 | 200 | 400 |
| 7 | 810 | - | 300 | 600 |
| 8 | 1215 | - | 450 | 900 |
| 9 | 2250 | - | 800 | 1600 |