Full Load Current Calculator

Full Load Current (FLC) Calculator — NEC Article 430

This calculator performs an instant lookup of motor full load current from NEC Table 430.248 (single-phase) and NEC Table 430.250 (three-phase). Per NEC 430.6(A)(1), these table values — not motor nameplate FLA — must be used for sizing conductors and branch-circuit protection devices.

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 exact full load current from the NEC table for your motor HP and voltage. Use this for conductor sizing and breaker selection.
• 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 Quick Reference — 460V Three-Phase

NEC Table 430.250 200 HP 460V full load current

For the direct lookup, 200 HP at 460V three-phase is 240 A in NEC Table 430.250. The minimum conductor ampacity screen is 300 A, and the inverse-time breaker screen is 600 A before final device selection, conductor derating, terminal limits, voltage drop, and equipment instructions are reviewed.

FLC vs FLA — The Critical NEC Distinction

NEC Article 430 requires using two 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 code violation. The NEC table values are intentionally conservative to account for motor manufacturing variations across brands.

NEC 430 Key Sections Reference

• 430.6(A)(1) — Mandates use of Table 430.248/430.250 values (not nameplate) for conductor and protection sizing
• 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.