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Service Loads & Motors calculator

Full Load Current Calculator

Enter motor HP, voltage, and phase to look up the NEC Table 430.248 or 430.250 full-load current. The calculator returns the selected table value for conductor and branch-protection review, keeps nameplate FLA separate for overload settings, and points the result into the next motor-circuit planning step.

Updated August 5, 2026

Enter motor HP, voltage, and phase to look up NEC Table 430.248/430.250 FLC, then use table FLC for conductor and branch-protection screens but not overload settings.

NEC table method: select HP -> select voltage -> select phase -> review conductor and branch-protection context from the calculated row

Enter HP, voltage, and phase below to confirm NEC table FLC before conductor, branch-protection, or nameplate-overload review

Source: NFPA 70, National Electrical CodeOpens in a new tab | Last reviewed: 2026-08-04

Final installation decisions must use the adopted NEC edition, equipment listings, and AHJ requirements.

Calculator Inputs

Quick Presets

Motor rated horsepower (HP). Common sizes: 1, 1.5, 2, 3, 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 200 HP

System voltage. NEC tables cover standard voltage ranges.

Single-phase uses NEC Table 430.248, three-phase uses NEC Table 430.250

Calculation Results

Enter values above to see calculation results

Field kit

Tools for FLC checks

Use the table current as a sizing reference, then compare field tools for measured current and nameplate documentation.

Compare clamp metersFor running current checksOpens in a new tabCompare inrush metersFor starting-current reviewOpens in a new tabFind overload relaysMatch the motor nameplateOpens in a new tab

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Calculation history

Example Calculations

Three-phase table lookupChoose HP, voltage, and phase, then use the returned NEC table FLC as the starting point for conductor and branch-protection review.InputsMotor HP: 10Voltage: 460 VPhases: Three phase
Larger motor branch-circuit handoffUse the selected table value as the handoff into conductor, device, terminal, derating, voltage-drop, and equipment-instruction checks.InputsMotor HP: 50Voltage: 230 VPhases: Three phase
More examples. Open to review 2 additional calculation examples.
High-horsepower NEC table lookupConfirm the exact HP, voltage, and phase in the calculator before using the selected table current in a documented branch-circuit review.InputsMotor HP: 200Voltage: 460 VPhases: Three phase
Single-phase table lookupSwitch the phase count to single-phase so the calculator uses the correct NEC table before the downstream review begins.InputsMotor HP: 5Voltage: 230 VPhases: Single phase

How to Use

Motor FLC Calculator - NEC 430.248 and 430.250

Enter motor HP, voltage, and phase to look up NEC Table 430.248 or 430.250. In the Article 430 workflow, these table values are used for conductor and branch-circuit protection review, while motor nameplate FLA remains the overload basis.

How to Use This Calculator

  1. Enter Motor HP — Standard NEMA motor sizes: 1, 1.5, 2, 3, 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 200 HP
  2. Select System Voltage — 115V, 200V, 208V, 230V, 460V, or 575V
  3. Select Phase Count — Single-phase (NEC 430.248) or three-phase (NEC 430.250)

What the Results Mean

  • NEC Table FLC — The table full-load current for the selected motor HP and voltage. Use this as the conductor and branch-protection review basis before equipment and AHJ checks.
  • Min Conductor Ampacity — FLC × 125% per NEC 430.22. This is the minimum ampacity your branch-circuit conductors must have.
  • Overload Protection Basis — Use actual motor nameplate FLA per NEC 430.32. Do not calculate the overload setting from table FLC.
  • Max Branch-Circuit Breaker — FLC × 250% for inverse time circuit breakers per NEC 430.52 Table 430.52(C)(1).

NEC Table 430.250 reference and result handoff

Use the selected HP, voltage, and phase count before carrying table FLC into conductor ampacity, branch-circuit short-circuit and ground-fault protection, disconnect, and documentation review. The result should stay tied to the motor entered on this page.

Use the lookup result in the next review

After the calculator returns the table FLC for your selected motor, continue into conductor ampacity, branch-circuit protection, terminal rating, derating, voltage-drop, and equipment-instruction review. Keep the nameplate FLA separate for overload settings.

FLC vs FLA — The Critical NEC Distinction

NEC Article 430 motor review uses different current values for different purposes:

  • Table FLC (Full Load Current) — From NEC Tables 430.248/430.250 → Used for conductor sizing (430.22), branch-circuit protection (430.52), and disconnect sizing.
  • Nameplate FLA (Full Load Amps) — From motor nameplate → Used exclusively for overload protection sizing (430.32).

Mixing these values is a common review error. The NEC table values are intentionally conservative to account for motor manufacturing variations across brands.

NEC 430 Key Sections Reference

  • 430.6(A)(1) — Points conductor and branch-protection sizing toward Table 430.248/430.250 values for the motor types covered here
  • 430.22 — Conductor ampacity ≥ 125% of motor FLC for continuous duty
  • 430.32 — Overload protection: commonly 125% of nameplate FLA when service factor is ≥1.15 or temperature rise is 40°C or less; otherwise 115% of nameplate FLA
  • 430.52 — Branch-circuit short-circuit protection: 250% max for inverse time breaker, 175% for dual-element fuse
  • 430.110 — Disconnect: 115% of motor FLC

Next Steps After the FLC Lookup

After the table value is confirmed, use the Motor Cable Size Calculator to keep voltage drop, terminal limits, and conductor ampacity together. For short-circuit and ground-fault device sizing, continue with the Motor Branch Protection Calculator.

Common Applications

Motor branch-circuit conductor sizing
Breaker and fuse selection for motor circuits
Overload relay sizing and coordination
More applications. Open to review 3 additional use cases.
Electrical permit load calculations
Motor control center (MCC) design
Industrial facility electrical design

Frequently Asked Questions

What is full load current (FLC) and how is it different from full load amps (FLA)?
Full Load Current (FLC) is the standardized current from NEC Tables 430.248/430.250 used as the conductor and branch-protection review basis. Full Load Amps (FLA) is the actual current on the motor nameplate. In the NEC Article 430 workflow, table FLC and nameplate FLA serve different tasks, so keep both values visible before the final equipment review.
How do I size a breaker for a motor using NEC 430.52?
Per NEC 430.52 and Table 430.52(C)(1), start with the table FLC returned by the calculator, choose the branch protective device type, and apply the matching percentage limit before standard-size, equipment-instruction, fault-duty, and local authority review.
Why does NEC use table values instead of nameplate current for conductor sizing?
NEC uses standardized table values because different manufacturers produce motors with varying nameplate currents for the same HP rating. Using table values ensures conductors are sized consistently regardless of which motor is eventually installed. This provides flexibility for motor replacement without rewiring. The table values are intentionally conservative to accommodate manufacturing variations across the industry.
What is the 125% rule in NEC 430.22 for motor conductors?
NEC 430.22 requires branch-circuit conductors supplying a single continuous-duty motor to have an ampacity not less than 125% of the motor FLC from NEC tables before terminal, ambient, conductor-count, voltage-drop, and equipment checks.

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