Plenty of people ring asking for three-phase when a bigger single-phase board would do the job. Here's how Glenn works it out.
Single-phase runs out at about 125 amps. That's a lot of house. Lights, power points, hot water, ducted air and a normal EV charger all sit inside it.
Three-phase earns its place when the equipment demands it. A submersible bore pump, a lathe, a big compressor, a three-phase welder, a commercial coolroom. These are built with three-phase motors and there's no single-phase version worth having.
Or when too much runs at once. A workshop where the compressor, the dust extraction and the welder all go together will flatten a single-phase board even if each machine on its own would be fine.
For EV charging, three-phase is where 22kW lives. A 22kW charger switched on all three phases doesn't need an Ergon control device, so it runs whenever you want. On single-phase, most homes can now have a 32A (7kW) charger on normal power, and that covers most people's driving.
If your loads don't fall into those groups, Glenn will say so and quote a single-phase board instead.
