NEMA Starter Size Chart
Every NEMA starter size from 00 to 9 with its continuous ampere rating and maximum horsepower per voltage, per NEMA ICS 2 — the standardized table every manufacturer’s NEMA-rated starter carries, which is why a Size 2 is a Size 2 whether it says Allen-Bradley, Square D, or Siemens on the door. Ratings are for normal (non-jogging) duty; 208 V systems use the 200 V column, and 460 V and 575 V share one column because ICS 2 rates them identically.
NEMA starter sizes 00–9
| NEMA size | Cont. A | 1φ 115 V HP | 1φ 230 V HP | 3φ 200 V HP | 3φ 230 V HP | 3φ 460/575 V HP |
|---|---|---|---|---|---|---|
| 00 | 9 | 1/3 | 1 | 1.5 | 1.5 | 2 |
| 0 | 18 | 1 | 2 | 3 | 3 | 5 |
| 1 | 27 | 2 | 3 | 7.5 | 7.5 | 10 |
| 1P | 36 | 3 | 5 | — | — | — |
| 2 | 45 | 3 | 7.5 | 10 | 15 | 25 |
| 3 | 90 | 7.5 | 15 | 25 | 30 | 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 |
How to pick a starter size
Find your motor's horsepower in the column for its voltage and read left to the smallest size whose rating covers it. The pick runs on HP, not amps — the HP ratings already account for locked-rotor inrush and breaking running current, which is what separates a motor-rated contactor from a lighting contactor with the same ampere number. Get the motor's full-load current from the motor FLA chart when you size the rest of the circuit — conductors, fuses, and the disconnect all key off FLC, and the motor circuit data chart rolls all of it, this table included, into one row per motor.
Two ratings share every catalog page: the continuous ampere rating shown here (the 8-hour enclosed rating) and a higher "service-limit" current the overload relay may ride up to. Select by the continuous rating; the service limit is headroom, not a selection number.
Jogging, plugging, and reversing duty
The table above is normal duty. Applications that jog, inch, plug, or reverse more than about five times a minute make the contactor interrupt stalled-motor current over and over, and ICS 2 publishes a separate, lower HP table for that service — roughly one full size of derate. A crane, a machine tool with a jog pedal, or a conveyor that bumps material into position should be sized from the jogging table (or as an IEC selection, category AC-4). If the duty is borderline, buy the size up; contactor tips are cheaper than downtime, but a welded contact takes the line down either way.
Common questions
What size NEMA starter do I need for a 10 HP motor?
At 460 V or 575 V three-phase, a 10 HP motor takes a NEMA Size 1 starter (rated exactly 10 HP). At 230 V it needs a Size 2 — the Size 1 tops out at 7½ HP there — and at 200/208 V it also needs a Size 2. Voltage matters as much as horsepower: the same motor drops a full starter size when the voltage doubles.
What is the difference between the continuous ampere rating and the horsepower rating?
The continuous ampere rating (9 A for Size 00 up to 2,250 A for Size 9) is the current the enclosed starter can carry all day. The HP ratings fold in what motors actually do — draw locked-rotor current at start and break running current — so they are the numbers to select by for a motor load. Pick by HP at your voltage; use the ampere rating only for non-motor loads the contactor might switch.
Does jogging or plugging change the starter size?
Yes. NEMA ICS 2 publishes a second, lower HP table for plugging and jogging duty (more than five operations per minute, interrupting stalled-motor current). The working rule of thumb: a jogging application needs roughly one size larger than this chart shows — a 20 HP, 460 V conveyor that jogs constantly belongs on a Size 3, not the Size 2 the normal-duty table allows.
What is a NEMA Size 1P starter?
The standard’s only half-size: a 36 A single-phase-only rating that slots between Size 1 and Size 2, rated 3 HP at 115 V and 5 HP at 230 V. It exists because single-phase motors in that band are common (compressors, pumps) and a full Size 2 is overkill. It has no three-phase rating at all.
Is a NEMA starter size the same as an IEC contactor rating?
No. NEMA sizes are standardized steps — any Size 3 from any manufacturer carries the same 30 HP at 230 V — while IEC contactors are rated per application by each manufacturer using utilization categories (AC-3 for normal motor duty, AC-4 for jogging). See the IEC vs NEMA starter chart for the mapping and trade-offs.
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