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Full Load Current Calculator

Calculate full load current for various electrical equipment including motors, transformers, and general loads.

Formulas Used

Single Phase Motor: I = (HP × 746) / (V × Eff × PF)
Three Phase Motor: I = (HP × 746) / (√3 × V × Eff × PF)
Three Phase General: I = kW × 1000 / (√3 × V × PF)
Three Phase Resistive: I = kW × 1000 / (√3 × V)

Notes

  • Motor efficiency typically ranges from 0.85 to 0.95 for standard motors
  • Power factor typically ranges from 0.8 to 0.95 for inductive loads
  • Use 1.0 power factor for resistive loads (heaters, incandescent lighting)
  • Per NEC 430.6, use motor nameplate current when available
  • Conductors must be sized at 125% of full load current (NEC 430.22)