Motor Start Current Calculator

25HP 480V motor - 150A inrush on DOL, what breaker and wire gauge? FLA, LRA, inrush kVA for DOL, star-delta, soft start, VFD per NEC 430. $4.99 one-time, no login.

Sizing a breaker or wire for a new motor and need to know the inrush current before you pull the trigger? Enter HP, voltage, and phase to instantly compare starting methods and get breaker size and wire gauge per NEC 430 — so you spec it right the first time.

Enter motor HP, voltage, phase, efficiency, and power factor. Compare four starting methods side by side: DOL (6x FLA), Star-Delta (2x), Soft Starter (3x), and VFD (1.5x). Shows FLA, LRA, inrush kVA, recommended breaker size, and wire gauge per NEC Article 430.

FEATURES:

• Full load amps (FLA) calculation for single and three phase
• Locked rotor amps (LRA) for each start method
• Inrush kVA calculation
• NEC 430 breaker sizing recommendation
• Wire gauge suggestion per NEC ampacity tables
• Single phase and three phase support

Built for electricians, controls engineers, and maintenance technicians. Works offline.