Thread: Running single phase machines off 3 phase

Think about it, all those houses all over Australia with a 3 phase connection all using single phase appliances.

Originally Posted by AndrewPatrol

Is it possible? I’m looking for another property but all my machines are single phase and I don’t want to get caught out limiting myself to only single phase places.

If you buy a property with 3 phase supply, more than likely just one or maybe two of those 3 phases will be used in the house running on different circuits from the consumer board, now that we have more electric cars, 3 phase is been offered by builders, so one of the phases can be used to charge the car.

The shed or workshop on the property will probably get all 3 phases for running machines that require them and from the sub consumer board in the shed you can take anyone of those phases with a neutral and earth and run a 240v circuit around the shed, if this has not already been done by the current owner.

Thanks . I was imagining there’d have to be some sort of balance between phases if one is used for lighting, one for saw (4hp - 20amp single phase, in my case) and one for say the dusty etc. but I reckon that’d be difficult. Hopefully by the time a whole area is taken into account it’d balance out? I don’t really understand it, can’t you tell.

Originally Posted by AndrewPatrol

Thanks . I was imagining there’d have to be some sort of balance between phases if one is used for lighting, one for saw (4hp - 20amp single phase, in my case) and one for say the dusty etc. but I reckon that’d be difficult. Hopefully by the time a whole area is taken into account it’d balance out? I don’t really understand it, can’t you tell.

It's up to the sparky to wire the building to roughly balance up the phases. A 20A machine will need its own circuit and breaker, so that could go on one phase. Maybe (15A) DC on another phase and all your 10A gear and lighting could be go on other phase.
Balancing only really becomes a problem if you have many machines on and under full load simultaneously - this is more like a workplace need than a DIY shed.

Originally Posted by AndrewPatrol

Thanks . I was imagining there’d have to be some sort of balance between phases if one is used for lighting, one for saw (4hp - 20amp single phase, in my case) and one for say the dusty etc. but I reckon that’d be difficult. Hopefully by the time a whole area is taken into account it’d balance out? I don’t really understand it, can’t you tell.

Balancing the load over 3 Phases is not really your problem.
The "Supply Authority" would wish for the load on all 3 phases from any particular supply transformer to be "approximately" balanced throughout the day, which is why they connect each of any "group" of three single-phase houses to a different phase.

See Does Current Flow Through The Neutral Wire? - YouTube