Phase Converter Wire Size Calculator & Reference

Use this reference to determine the correct wire gauge for your phase converter installation. Proper wire sizing ensures safe operation, prevents voltage drop, and keeps your equipment running at peak efficiency. For questions, call our experts at (800) 417-6568.

How to Calculate Wire Size for a Phase Converter

1. Find your equipment FLA — Check the motor nameplate for Full Load Amps (FLA)
2. Calculate input amps — Single-phase input draws approximately 2x the equipment FLA
3. Select wire gauge — Use the table below based on your calculated input amps and run length
4. Size your breaker — Breaker = 2x equipment FLA (minimum)

Wire Size Reference Table (Copper, 75°C, Single-Phase Input)

Note: Always verify against NEC Table 310.16. Consult a licensed electrician for your specific installation. Longer runs (>50 ft) require upsizing one gauge.

Voltage Drop Rule of Thumb

Keep voltage drop under 3% from your breaker panel to the phase converter. For runs over 50 feet, upsize one wire gauge. For runs over 100 feet, upsize two gauges. Excessive voltage drop causes hard starts, overheating, and premature motor failure.

Three-Phase Output Wire Sizing

The three-phase output wire (converter to equipment) is sized at the equipment FLA — not the 2x multiplier used for single-phase input. Use NEC Table 310.16 for your equipment nameplate FLA to select the correct output wire gauge.

Related Resources

• Motor Wire Size Chart
• Single Phase Wire Size Reference
• Wiring Diagram Phase Converter Handbook
• Phase Converter FAQ