1. Ratings, three-phase, full-voltage single-speed controllers
Scroll table left / right →NEMA ICS 2-2000 Table 2-4-1, limited plugging and jogging duty. Reprinted in Rockwell 500-TD014D pp. 3-4 (sizes 00-8) and Square D Type S catalog p. 13 (sizes 00-7); Size 9 per Allen-Bradley Bulletin 509 catalog p. 1-35. A circulating claim of 35 HP at 230 V for Size 3 is wrong; both manufacturer reprints of the NEMA table give 30 HP.| Size | Continuous A | Service-limit A | HP 200 V | HP 230 V | HP 460 V | HP 575 V |
|---|
| 00 | 9 | 11 | 1.5 | 1.5 | 2 | 2 |
| 0 | 18 | 21 | 3 | 3 | 5 | 5 |
| 1 | 27 | 32 | 7.5 | 7.5 | 10 | 10 |
| 2 | 45 | 52 | 10 | 15 | 25 | 25 |
| 3 | 90 | 104 | 25 | 30 | 50 | 50 |
| 4 | 135 | 156 | 40 | 50 | 100 | 100 |
| 5 | 270 | 311 | 75 | 100 | 200 | 200 |
| 6 | 540 | 621 | 150 | 200 | 400 | 400 |
| 7 | 810 | 932 | n/a | 300 | 600 | 600 |
| 8 | 1215 | 1400 | n/a | 450 | 900 | 900 |
| 9 | 2250 | n/a | n/a | 800 | 1600 | 1600 |
Service-limit current, per ICS 2 paragraph 2-321.20: the maximum rms current the controller is permitted to carry for protracted periods in normal service, at temperature rises above the continuous-rating test values. The overload relay current rating, or trip current of other protective devices used, shall not exceed the service-limit current of the controller.
2. Plugging and jogging duty derate
The derated table applies when duty involves more than five openings or closings per minute, or more than ten in a ten-minute period: plug-stop, plug-reverse, or jogging service (ICS 2 footnote as printed in both catalogs; Eaton A200 catalog cites the rule as NEMA ICS 2-321). Sizes 7 through 9 carry no published jog or plug ratings. Square D publishes operation-rate limits for Size 6 and 7: 3 operations per minute continuous, 15 per minute for a maximum of 3 minutes under jogging or plugging duty.
Scroll table left / right →NEMA ICS 2-2000 Table 2-4-3. Effect: jogging or plugging service moves the application up one size. A 25 HP, 460 V jog application requires Size 3; its standard-duty rating alone would allow Size 2.| Size | HP 200 V | HP 230 V | HP 460 V | HP 575 V | Standard-duty HP 460 V, for comparison |
|---|
| 00 | 1 | 1 | 1.5 | 1.5 | 2 |
| 0 | 1.5 | 1.5 | 2 | 2 | 5 |
| 1 | 3 | 3 | 5 | 5 | 10 |
| 2 | 7.5 | 10 | 15 | 15 | 25 |
| 3 | 15 | 20 | 30 | 30 | 50 |
| 4 | 25 | 30 | 60 | 60 | 100 |
| 5 | 60 | 75 | 150 | 150 | 200 |
| 6 | 125 | 150 | 300 | 300 | 400 |
3. Overload relay trip classes
Scroll table left / right →IEC definition and bands: ABB publication 1SXU106043B0201. All classes: no trip at 1.05x setting current; trip within 2 hours at 1.2x. NEMA/UL frames the same classes as maximum trip time in seconds at 600% of trip rating. Setting current is motor nominal current, not trip current.| Class | Definition (IEC 60947-4-1) | Trip band at 7.2x setting current | Selection |
|---|
| 10A / 10 | Max 10 s at 7.2x Ie | 4-10 s | Low-inertia loads that must not stall long; A-B eutectic: J heater element |
| 20 | Max 20 s at 7.2x Ie | 6-20 s | Default for general purpose motors; A-B eutectic: W heater element |
| 30 | Max 30 s at 7.2x Ie | 9-30 s | High-inertia starts; A-B eutectic: WL element; Square D slow-trip SB series |
| 5-30 electronic | Programmable | per setting | Rockwell E300: class 5-30, trip at 120% FLA; Eaton C440: 10A/10/20/30; A-B SMP: 10/15/20/30 |
4. Thermal unit (heater) selection rules, Square D melting alloy
Scroll table left / right →Square D, Overload Relays and Thermal Unit Selection, 5/98, pp. 19-21. Example from the Schneider Digest: Size 1, motor FLA 17.0 A, SF 1.15: thermal unit B32, trip rating 16.0 x 1.25 = 20.0 A.| Condition | Selection |
|---|
| Basis | Motor nameplate full-load amps. NEC/HP-derived values only as tentative fallback when the nameplate is unavailable. |
| Assumed ambient | Motor and controller both at 40 C or less. Selection tables assume this. |
| Service factor 1.15-1.25 | 100% of nameplate FLA |
| Service factor 1.0 | 90% of nameplate FLA |
| Controller 10 C hotter than motor location | Multiply selection FLA by 0.9 (SF 1.15-1.25) or 0.8 (SF 1.0) |
| Controller 10 C cooler than motor location | Multiply by 1.05 (SF 1.15-1.25) or 0.95 (SF 1.0) |
| Ambient-compensated bimetallic | 1.0x (SF 1.15-1.25) or 0.9x (SF 1.0), independent of controller ambient |
| Slow-trip Class 30 (Type SB) | Select from standard Type B table at 93% FLA (SF 1.15-1.25) or 84% (SF 1.0), substitute SB prefix. Available sizes 0-2 and some Size 3. |
| Wye-delta (Class 8630) | Divide delta-connected FLA by 1.73 before selection |
| Trip current rating | 125% of the minimum FLA listed for the selected thermal unit |
5. Manufacturer class designations
Scroll table left / right →Sources: Square D Type S catalog 5/98; Rockwell 500-TD014D and Bulletin 505/509 catalogs; GE Control Catalog Section 1 (CR306: nonreversing, non-combination, NEMA 00-5, 600 V max); Eaton A200 catalog and Freedom series Vol. 5 CA08100006E; Siemens NEMA starter brochures.| Manufacturer | Contactor | FVNR starter | Reversing | Combination | Other |
|---|
| Square D (Type S) | Class 8502 | Class 8536 | Class 8736 (contactors 8702) | 8538/8539 (fusible/CB); reversing 8738/8739 | 8810/8811/8812 multispeed; 8630 wye-delta; 8640 part-winding |
| Allen-Bradley | Bulletin 500 | Bulletin 509 (sizes 00-9) | Bulletin 505 | 512 (fusible), 513 (CB) | 502/503/506/507 enclosed and combination variants |
| GE | CR305 / CR385 | CR306 (00-5), CR386 (6-9) | CR309 | CR307/CR308/CR310/CR311 | |
| Eaton / Cutler-Hammer | A201; Freedom CN15/CN55 | A200 (00-9); Freedom AN16 | A210, A250 (sizes 5-9); Freedom AN56 | | A900 two-speed |
| Siemens | | Class 14 (ESP200 overload) | Class 22 | | |
6. Device data by size
Scroll table left / right →Rockwell 500-TD014D pp. 3-6, Bulletin 500/509 line, 2-3 pole AC coil values; 4-5 pole coils run higher. Coil operating range 85-110% of rated voltage (both Rockwell and Square D). Closing inrush includes DC offset. n/p: not published. Neither ICS 2 nor the catalogs publish a single electrical-life figure for NEMA starters; Rockwell publishes AC-3/AC-4 load-life curves per IEC 947-4 test conditions instead, so treat any flat electrical-life claim as unsupported.| Size | Mech. life, operations | Pickup / dropout, ms | Coil inrush / sealed VA (60 Hz) | Max closing inrush, A peak |
|---|
| 00 | 10,000,000 | 20 / 16 | 70 / 8 | 87 |
| 0 | 10,000,000 | 21 / 16 | 192 / 29 | 140 |
| 1 | 10,000,000 | 22 / 14 | 192 / 29 | 288 |
| 2 | 10,000,000 | 27 / 13 | 240 / 29 | 483 |
| 3 | 5,000,000 | 37 / 20 | 660 / 45 | 947 |
| 4 | 5,000,000 | 27 / 20 | 1225 / 69 | 1,581 |
| 5 | 5,000,000 | 25 / 18 | 1490 / 96 | 3,163 |
| 6 | 5,000,000 | 25-79 / 10-22 | 4860 / 254 | 6,326 |
| 7 | n/p | 88 / 40 | DC coil, control transformer fed | 9,470 |
| 8 | n/p | 88 / 45 | DC coil, control transformer fed | 14,205 |
Sources
1. NEMA ICS 2-2000, Tables 2-4-1 and 2-4-3, paragraph 2-321.20 (table identities per NEMA errata memo, May 2002; values via manufacturer reprints below).
2. Rockwell Automation publication 500-TD014D-EN-P, NEMA Contactor and Starter Specifications, March 2023.
3. Square D, Type S Contactors and Starters, Class 8536/8502/8736/8702/8810/8811/8812 catalog, 5/98.
4. Square D, Overload Relays and Thermal Unit Selection, 5/98.
5. Allen-Bradley Bulletin 509 catalog pages 1-33 to 1-35; Bulletin 505 catalog 505-CT003.
6. ABB publication 1SXU106043B0201, Thermal Overload Relays, Tripping Class 20.
7. Rockwell publication 193-TD006, E300/E200 Electronic Overload Relay Specifications.
8. GE Control Catalog, Section 1, NEMA Full Voltage Power Devices.
9. Eaton Cutler-Hammer A200 catalog (Jan 2006); Freedom series, Vol. 5 CA08100006E.
Related: VFD feeder sizing, unit height by amperage, renewal parts.
