Single phase and three phase electricity explained

Apr 15, 2019 | Getting started with solar

When speaking to a solar power retailer, you might have gotten the question if you have single phase or three phase electricity at your property. In this article we look at what single phase and three phase electricity is and how you can find out what you have.

Single phase

Single phase electricity is the regular electricity we use to power our TV and charge our phones with.  It’s 230 volts at 50 hertz and the standard for the socket is AS/NZS 3112.

Most properties in Australia only have single phase.

 

Three phase

Three phase is what you could call ‘heavy duty’ electricity. Instead of 230 volts, a much higher voltage of 400 volts comes out of the socket. To accomplish this a property with three phase electricity is connected to the grid through three live wires, compared to just one for a single phase property.

As you can imagine, three phase electricity isn’t designed to power your TV. Instead, it’s for appliances that draw a lot of electricity. Like heavy duty compressors, industrial freezers/air conditioners, industrial ovens, etc.

These are mostly things you’ll find in industrial and large commercial environments, but sometimes also in large homes that can have large air conditioners or pool pumps running.

There’s also situations where someone might decide to install it at home for use in the garage for a compressor, car lift, welder or a pottery kiln for example.

The standard for three phase sockets is AS/NZS 3123. You can have both regular sockets and high voltage sockets in a property with three phase electricity

A single phase AS/NZS 3112 outlet

A three phase AS/NZS 3123 outlet

How do you know what you have at home

Most people that have three phase electricity in their home are well aware that they have it as there are higher connection fees and higher annual charges from your electricity company.

If you’re not sure however, you could obviously have a look to see if you have one of those bigger AS/NZS 3123 sockets anywhere, but the simplest way is to have a look at your home’s switchboard.

When you’ve located the switchboard in your home, find the circuit breaker that is labeled ‘Main Switch’. If this is a single circuit breaker, you have single phase electricity. If you see three circuit breakers joined together, you have three phase electricity.

It’s as simple as that.

A single phase circuit breaker

A three phase circuit breaker

What this means for a solar power system

In your solar power system you have an inverter that converts the high voltage electricity from your solar panels to the electricity that you can use to power your TV for example.

Dedicated three phase inverters exist for homes that have three phase electricity. While you don’t have to use three phase inverter, it’s often recommended you do get one and in many countries it’s also required by the energy company.

The reason for that is that with a three phase property, you have three live wires going into your home, instead of one. That means you are able to spread the energy generated from your solar power system across three wires instead of one. That reduces the chance of having issues with voltage rises.

That can result in your inverter throttling how much electricity it sends to the grid. Which reduces the return of your solar power system.

While it’s usually recommended you get a dedicated three phase inverter, there are some other things to keep in mind like price and if you want to have a solar power battery installed in the future. We recommend you discuss this with your solar power retailer when making a decision.

(RELATED: You might have heard about micro-inverters. Find out what they are and if they are relevant for you in this article about Panel Level Optimisation)

 

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