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 deliver power to special three-phase appliances that have high power demands. For example, a welder. Three phase power can also be installed at homes or businesses across Australia if more power is required than single phase provides.
Most houses have single-phase power, which is supplied by two wires, known as active and neutral. Three-phase power is supplied by four wires, three active wires and 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. If you install an electric vehicle charger that is high powered, it is likely to bring about the need for a three-phase supply and switchboard. This is why it is important to choose low powered equipment where it makes sense.
How much extra electricity does induction cooking use at peak moments?
How much electricity an induction cooktop will draw depends on the “connected load” rating of the appliance. This is often shown in the specifications before you even buy the appliance.
This rating tells the electrician the maximum power that the appliance will ever draw. Many induction cooktops are installed with more circuit capacity than is required, sometimes raising the possibility of unnecessary upgrades. AS3000 (the wiring rules) gives electricians a recommended circuit size (in amps) for cooktops of different maximum power. These recommendations take into account that you will almost never use all of your cooktop zones at maximum power and, if you do, it would not be for very long. If you would like more details, an article on this topic was published on One Step Off the Grid.
Are there any tips or other options for households (including to minimise costs or upgrades)?
Selecting appliances that are energy efficient and have lower power demand 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. EV chargers should be as slow as you can realistically manage. Many people successfully charge their EVs using the 10 amp portable charge cord provided with their car and so don’t even need to install a dedicated wallbox.
How much does it cost to upgrade?
The cost of an upgrade will depend 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. A single-phase switchboard upgrade costs around $1300 to $1800. A three-phase switchboard upgrade with cost around $1600 to $2400. An upgrade to supply three-phase power to your house could cost a total $4,000 to $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 early when planning your ‘Getting Off Gas’ journey.
