Phase Converter Installation: What to Expect and How to Prepare

You've chosen the right rotary phase converter for your application — now what? Phase converter installation is straightforward when you know what to expect. This guide walks you through pre-installation planning, what your electrician needs to know, and common mistakes to avoid.

Important: Phase converter installation should always be performed by a licensed electrician. This guide is designed to help you prepare and have informed conversations with your installer — not as a DIY wiring manual.

Pre-Installation Planning

1. Verify Your Electrical Panel Capacity

Your existing single-phase electrical panel needs enough available amperage to feed the phase converter. Check with your electrician that:

  • Your main panel has sufficient capacity (amps) for the converter's input requirements
  • There's space for a new breaker (or sub-panel)
  • Your utility service can handle the additional load

Pro tip: A 20 HP phase converter typically draws around 80–100 amps on a 240V single-phase circuit. Make sure your service can support this before purchasing.

2. Choose the Right Location

Your phase converter needs a suitable installation location:

  • Indoor or covered area — protected from rain and direct weather exposure
  • Well-ventilated space — the converter generates some heat during operation
  • Near your electrical panel — shorter wire runs save money and reduce voltage drop
  • Accessible for maintenance — though Phoenix Phase Converters require minimal upkeep
  • Solid mounting surface — wall-mount or floor-mount depending on the model

3. Plan Your Wire Sizing

Wire sizing depends on three factors: the converter's amperage, the distance from your panel, and local code requirements. Your electrician will calculate this, but as a general reference:

  • Shorter runs (under 50 feet): Standard wire sizing per NEC ampacity tables
  • Longer runs (50–100+ feet): Upsize wire to compensate for voltage drop
  • Both input AND output wiring must be properly sized

Installation Overview: What Your Electrician Will Do

Step 1: Install the Input Breaker

A properly sized two-pole breaker is installed in your single-phase panel to feed the phase converter. The breaker size is determined by the converter's input amperage rating.

Step 2: Run Input Wiring

Single-phase wiring (two hots + ground, or two hots + neutral + ground depending on your setup) is run from the panel to the converter's input terminals.

Step 3: Mount and Connect the Converter

The phase converter is mounted in its designated location and input wiring is terminated at the converter. Phoenix Phase Converters come with clearly labeled terminals and wiring diagrams.

Step 4: Install a Three-Phase Sub-Panel (Recommended)

For shops with multiple machines, the best practice is to install a three-phase sub-panel fed by the converter's output. This gives you:

  • Individual breakers for each machine (easier troubleshooting)
  • Proper overcurrent protection per NEC requirements
  • Easy expansion when you add equipment later
  • Clean, organized, code-compliant installation

If you're only running one machine, your electrician can wire directly from the converter output to the equipment.

Step 5: Run Output Wiring to Equipment

Three-phase wiring (three hots + ground) is run from the sub-panel or converter output to each piece of equipment.

Step 6: Test and Verify

Your electrician will start the converter, verify proper rotation, and check voltage balance across all three phases at each machine. Phoenix Phase Converters produce balanced, clean three-phase power — your electrician should see near-equal voltage on all three legs.

What Your Electrician Needs to Know

Not every electrician has installed a phase converter before. Share these key points:

  • The converter produces true three-phase power — it's wired like any three-phase source
  • Output is three hots (L1, L2, L3) plus ground — no neutral on the three-phase side
  • The converter should be on a dedicated breaker — don't share circuits with other loads on the input side
  • A three-phase sub-panel is strongly recommended for multi-machine shops
  • Phoenix Phase Converters include detailed wiring diagrams with every unit
  • Our tech support line is available if your electrician has questions: 800-417-6568

Common Installation Mistakes

Undersized Wiring

Using wire that's too small causes voltage drop, overheating, and poor performance. Always size wire based on the converter's full-load amperage and the length of the run.

Improper Breaker Sizing

The input breaker must match the converter's specifications — not the individual machine ratings. Your converter's manual specifies the correct breaker size.

Skipping the Sub-Panel

Daisy-chaining multiple machines off the converter output without individual breakers creates safety hazards and code violations. A sub-panel costs a little more upfront but is the right way to do it.

Poor Location Choice

Installing outdoors without protection, in a dusty environment without filtration, or too far from the panel (causing expensive long wire runs) are common mistakes that are easy to avoid with planning.

NEC Code Considerations

Phase converter installations must comply with the National Electrical Code (NEC), specifically:

  • Article 455 — Phase Converters (covers installation requirements)
  • Article 408 — Switchboards, Switchgear, and Panelboards (for sub-panel installations)
  • Local amendments may apply — your licensed electrician will know your jurisdiction's requirements

A permitted, inspected installation protects you and ensures your insurance coverage remains valid.

How Long Does Installation Take?

A typical phase converter installation takes 2–4 hours for an experienced electrician. Complex multi-machine setups with sub-panels may take a full day. The converter itself is ready to go out of the box — most of the installation time is running and terminating wire.

Ready to Install? We're Here to Help

Whether you're planning an installation or your electrician has questions mid-job, our expert team is a phone call away. Call 800-417-6568 for free installation support.

All Phoenix Phase Converters are Made in the USA, backed by a lifetime warranty, and include complete wiring diagrams. Browse our rotary phase converters, check out our sizing guide, or read the Ultimate Guide to Phase Converters for everything you need to know.