The definitive electric motor FLA chart for US electrical installations is NEC Table 430.250 (Full-Load Currents in Amperes, Alternating-Current Motors). When sizing branch circuit conductors, short-circuit protection, and ground-fault devices, the National Electrical Code (NEC) mandates using the baseline values from this chart—not the specific amperage printed on the motor's physical nameplate. For a standard 10 HP, 3-phase, 460V motor, the chart FLA is exactly 14 Amps.
How to Read the NEC Electric Motor FLA Chart
Before jumping to the data, you must understand how to map your physical installation to the correct column. Table 430.250 is organized by Horsepower (HP) on the far left, followed by voltage columns for single-phase and three-phase systems.
Which column applies to your installation?
Match your supply voltage to the closest standard nominal column. If your facility supplies 240V, use the 230V column. If your facility supplies 208V, use the 200V column (or interpolate if required by your local inspector, though 200V is the standard NEC bucket). For 480V systems, use the 460V column. The chart assumes standard 60Hz operation; if you are operating a 50Hz motor, these values are invalid and you must use the manufacturer's specific 50Hz data.
What about temperature ratings?
A common point of confusion is looking for a 60°C or 75°C temperature column in the motor FLA chart. Table 430.250 does not have temperature columns. It only provides the baseline current. You apply temperature derating later, when you take the calculated ampacity over to NEC Table 310.16 to select your actual wire gauge (AWG/kcmil) and insulation type (THHN, XHHW, etc.).
Complete AC Motor FLA Data Table (NEC 430.250)
The table below contains the standard NEMA horsepower ratings queried most frequently on the jobsite. Bookmark this section for quick reference. Note: For motors larger than 200 HP, or for non-standard horsepower ratings, NEC 430.250 requires you to calculate the FLA based on the motor's actual nameplate current or use the next higher standard HP rating.
| HP | 1-Phase 115V | 1-Phase 230V | 3-Phase 200V | 3-Phase 230V | 3-Phase 460V |
|---|---|---|---|---|---|
| 1/2 | 9.8 | 4.9 | 2.1 | 1.8 | 0.9 |
| 3/4 | 13.8 | 6.9 | 2.9 | 2.5 | 1.3 |
| 1 | 16 | 8 | 3.5 | 4.2 | 2.1 |
| 1.5 | 20 | 10 | 4.8 | 5.2 | 2.6 |
| 2 | 24 | 12 | 6.3 | 6.8 | 3.4 |
| 3 | 34 | 17 | 8.7 | 9.6 | 4.8 |
| 5 | 56 | 28 | 15.2 | 15.2 | 7.6 |
| 7.5 | 80 | 40 | 22 | 22 | 11 |
| 10 | 100 | 50 | 28 | 28 | 14 |
| 15 | — | — | 42 | 42 | 21 |
| 20 | — | — | 54 | 54 | 27 |
| 25 | — | — | 68 | 68 | 34 |
| 30 | — | — | 80 | 80 | 40 |
| 40 | — | — | 104 | 104 | 52 |
| 50 | — | — | 130 | 130 | 65 |
| 60 | — | — | 154 | 154 | 77 |
| 75 | — | — | 192 | 192 | 96 |
| 100 | — | — | 248 | 248 | 124 |
| 125 | — | — | 312 | 312 | 156 |
| 150 | — | — | 372 | 372 | 186 |
| 200 | — | — | 480 | 480 | 240 |
Source: NFPA 70 (National Electrical Code), Table 430.250. Values are for standard 60Hz AC motors. Single-phase motors above 10 HP are generally not standard NEMA frames and require custom engineering.
What This Chart Cannot Tell You (And When to Derate)
While the electric motor FLA chart is the legal baseline for sizing branch circuits, it is not a crystal ball. Here is what the table omits, and how you must adjust your calculations in the real world.
1. The Chart Does Not Show Locked Rotor Amps (LRA)
FLA is the current the motor draws at full mechanical load while running. It does not tell you the massive inrush current drawn during startup (Locked Rotor Amps), which can be 6 to 8 times the FLA. If you need LRA to size a soft starter or verify voltage dip, you must read the motor nameplate or use NEC Table 430.7(B) using the motor's Code Letter.
2. Modern Premium Efficiency Motors Draw Less Than the Chart
The NEC chart is deliberately conservative. Modern IE3 and IE4 premium efficiency motors (such as those tracked by the US Department of Energy) often have physical nameplate FLA values 5% to 15% lower than the NEC chart. However, NEC 430.6(A)(1) strictly forbids using the lower nameplate value for sizing branch circuit conductors and short-circuit protection. You must use the chart value to ensure the circuit can handle a future replacement motor that might be less efficient.
3. How Derating Modifies the Base Value
The FLA chart gives you a raw number. To get your actual wire size, you must apply a sequence of multipliers:
- Continuous Duty Multiplier: Per NEC 430.22, multiply the chart FLA by 1.25 (125%) for continuous duty motors (running 3 hours or more).
- Ambient Temperature Derating: If the conduit runs through an environment hotter than 30°C (86°F), you must apply the correction factors from NEC Table 310.15(B)(1).
- Conduit Fill Derating: If you pull more than three current-carrying conductors in a single raceway, apply the adjustment factors from NEC Table 310.15(C)(1).
Example: A 10 HP, 460V 3-phase motor has a chart FLA of 14A. Multiply by 1.25 = 17.5A. You look up 17.5A in the 75°C column of Table 310.16, which points to 14 AWG (rated 20A). However, if this wire is in a 50°C boiler room, the 75°C ampacity must be derated by 0.75. 20A × 0.75 = 15A, which is below your 17.5A requirement. You must step up to 12 AWG.
Frequently Asked Questions About Motor FLA Lookups
What if my motor voltage is 208V or 240V but the chart says 230V?
The NEC uses nominal motor voltages (115V, 230V, 460V) to represent standard system voltages (120V, 240V, 480V). If your facility measures 240V at the panel, use the 230V column. If you are on a 208V wye system, use the 200V column. The slight voltage variance is already accounted for in the safety margins built into the NEC tables.
Why is the physical nameplate FLA lower than the NEC electric motor FLA chart?
Motor manufacturers design modern motors to be highly efficient, meaning they draw fewer amps to produce the same mechanical horsepower. The NEC chart represents a historical, standardized baseline designed to ensure that if a high-efficiency motor fails and is replaced by a standard-efficiency motor, the existing wiring and breakers will not overheat. Always use the chart for wire/breaker sizing, but use the nameplate for overload relay settings.
Do I use the chart value or the nameplate value to set the overload relay?
You must use the motor nameplate FLA. Per NEC 430.32, overload relays (heaters) are sized to protect the specific motor winding from thermal damage. Because overload relays are calibrated to the exact motor installed, you use the physical nameplate amps, typically setting the dial or selecting the heater block at 100% to 115% of the nameplate FLA depending on the motor's service factor.
How do I size a breaker if the calculated FLA doesn't match a standard breaker size?
Short-circuit and ground-fault protection (breakers/fuses) are sized using NEC Table 430.52. For a standard inverse-time breaker, you multiply the chart FLA by 2.5 (250%). If the resulting number does not correspond to a standard breaker size listed in NEC 240.6 (e.g., 15, 20, 25, 30, 35, 40A), NEC 430.52(C)(1) Exception No. 1 allows you to round UP to the next standard size. If the motor trips the breaker on startup, Exception No. 2 allows you to increase the multiplier up to 400% for standard breakers, provided the engineer approves.
