Electrical Planning – Do You Need 3 Phase Power?

3 phase power is used for heavy duty electrical appliances.

So what is 3 phase power?……………….When power is generated at the power station it comes out as Alternating Current (AC) in three separate phases which are transmitted via individual cables. When power is required the three phases can be combined (3 Phase) or separated(Single Phase).

A Typical House

Most houses only have single phase power.

All the typical electrical equipment in your house such as TV, fridges, freezers lights rub on single phase.power.

Reasons for 3 Phase

The only time a domestic house will need three phase power supply is likely to be:

  • If you have a really big house with a large capacity air conditioner.
  • If you want to have an Electrical Instantaneous Water Heater.
  • If you are want are a DIY enthusiast and want to run a commercial size arc welder (Single Phase power should be OK for 275 Amps which is enough for 10mm steel.)

For a new house on a farm where you want to run farm machinery it may be a different matter.

What happens with 3 Phase

If 3 phase was run to your house and you didn’t need actually need it, it simply means that your single phase circuits (power points, lights, oven) would be shared out over the 3 phases as evenly as possible.

What this can mean if their is a power failure that only affects one phase you will still have some power.

For a large house this might be the way to go, but it should not be considered as totally necessary, especially as it will cost substantially more.


If you think you might need 3 phase power I would suggest you contact an electrical contractor and have a chat with them.

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