CHAPTER 3: HOW TO GET OFF GAS
Wiring and electrical requirements
How to know if you need to upgrade your circuits
Almost every home that wants to go all electric will need some adaptations to the existing switchboard or require a larger switchboard to cope with the energy input. This is because some of the new appliances that are installed will need their own dedicated electrical circuits and circuit breakers located at the switchboard. There is often not enough room in the existing switchboard for these extra circuits.
Most houses in Australia have a single-phase grid connection that allows them to draw a maximum of 63 amps of power. Some older, inner-city homes that haven’t been subject to significant renovation may have a 32 or 40-amp connection. It is also possible to have a single-phase connection with greater than 63 amps. If you multiply the amps by the power voltage you get the amount of power your appliances can draw, which is measured in watts.
Appliances that may need their own circuits include induction cooktops, reverse-cycle air conditioners, heat pump hot water units, electric vehicle chargers, solar panels and battery systems. In some cases, the switchboard will not have the electrical capacity to handle the additional appliances. This means the supply to the house may need to be upgraded and the rating of the main switch increased. If the additional appliances create a large load, (such as when an electric vehicle charger is added) a three-phase electrical upgrade is required.
What is three-phase electricity?
A three-phase switchboard is a powerful electrical switchboard which is often used in commercial and industrial buildings as it can help prevent blackouts and other power disruptions. Three phase power can also be installed at homes or businesses across Australia. It is a more stable and consistent form of electricity that is perfect for businesses or homes with high-power needs.
Most houses have single-phase power, which is supplied by two wires, an active and a neutral. Three-phase power is supplied by four wires, three actives and a neutral. Because you now have three active wires instead of one you can now supply three times as much power. You can also run higher voltage 415-volt appliances, such as large air conditioning equipment. Electric vehicle chargers are likely to require a load that tips you over from single phase to the need for a three-phase supply and switchboard, but some do not. Large air conditioning and induction cooktops may also require a larger load.
How much extra electricity does induction cooking use at peak moments?
How much electricity an induction cooktop will draw depends on the size of the appliance. Induction cooktops are generally connected to a 32-amp circuit breaker. They may use more than this for short periods, but they will generally be below 32 amps.
Are there any tips or other options for households (including to minimise costs or upgrades)?
Selecting appliances that are energy efficiency and have lower energy use will help you work with your existing household power system and supply. Extra space can sometimes be created in the existing switchboard by replacing a combination of safety switches and circuit breakers (CB’s) with residual current circuit breakers (RCBO’s). Smaller air conditioners and heat pump hot water heaters do not always require dedicated circuits to your switchboard, reducing costs and space in the switchboard.
How much does it cost to upgrade?
Depending on where you are located, what kind of dwelling you are looking to upgrade, where the switches are located and how your existing power system is designed will affect the price of an upgrade. A single-phase switchboard upgrade costs around $1300 to $1800. A three-phase switchboard upgrade with cost around $1600 to $2400. A mains upgrade to supply three-phase power to your house could cost a total $4-5,000 including switchboard and other electrical works.
All homes and premises are different so prices and issues will vary from place to place. Consult your electrician when planning your ‘Getting Off Gas’ journey.