Three-phase power is one of those things that sounds technical and confusing but is actually pretty simple. If you're considering solar panels, an EV charger, ducted air conditioning, or commercial equipment — you might need it. Here's the plain-English explanation.
Single Phase vs Three Phase — The Simple Version
Single phase is like a single-lane road. It delivers power through one active wire and one neutral wire. It's what most Australian homes have, and it provides up to about 63A at 230V — roughly 14.5kW of total capacity.
Three phase is like a three-lane highway. It delivers power through three active wires and one neutral wire. Each phase provides the same capacity, giving you up to about 43.5kW total — three times the capacity of single phase.
Think of it like water pressure: single phase is a garden hose, three phase is three garden hoses. Same pressure, but three times the flow.
What Uses Three Phase Power?
In Homes
- Ducted air conditioning — large ducted systems (10kW+) often require three-phase power
- EV chargers — three-phase chargers (11-22kW) charge vehicles 2-3x faster than single-phase
- Large solar systems — three-phase inverters (typically 10kW+) distribute solar generation evenly across phases
- Pool heating — large heat pumps may require three-phase supply
- Workshops — serious workshop equipment (welders, lathes, compressors) often needs three-phase
In Commercial Settings
- Commercial kitchen equipment (ovens, dishwashers, cool rooms)
- Industrial machinery and motors
- Large HVAC systems
- Lifts and escalators
- Server rooms and data centres
Do I Have Three Phase Power Already?
Easy ways to check:
- Check your switchboard — if you have three rows of circuit breakers or a "3-pole" main switch, you likely have three-phase
- Check your meter — a three-phase meter is wider and has more terminals than a single-phase meter
- Check outside — three-phase has three (or four) wires coming from the street to your property, versus two wires for single-phase
- Ask us — we can check with a multimeter in 30 seconds
Getting Three Phase Power Installed
If you currently have single phase and need three phase, the process involves:
- Application to your energy distributor (Ausgrid in Sydney's Eastern Suburbs) for a supply upgrade
- Ausgrid assessment — they'll confirm three-phase is available in your street (it usually is in urban areas)
- Ausgrid installation — they run the additional phases from the street to your meter. This is their scope and their cost
- Electrician switchboard upgrade — your switchboard needs to be upgraded to a three-phase board with appropriate distribution
Costs
- Ausgrid supply upgrade: $500–$2,000+ (varies based on distance and complexity)
- Switchboard upgrade to three-phase: $2,000–$4,000 (including new board, breakers, and three-phase main switch)
- Total typical cost: $3,000–$6,000
The timeframe is usually 4-8 weeks, with most of that being Ausgrid's scheduling rather than the electrical work itself.
Need to assess whether three-phase power is right for your home or business? Call Randwick Electrical on 0413 707 758 for honest advice.