To city-siders, there may appear to be more plug-in electric vehicles (EVs) on the road. But perhaps that’s not surprising, given sales are up in Australia, with more sold in the first half of 2023 than in all of 2022.

While EVs make up less than 10 per cent of the new car market, this changing appetite will only get stronger with more incentives and choice. The federal government said it will introduce a fuel efficiency standard – like other developed nations – to limit the greenhouse gas emissions produced by our cars. This move may end up turbocharging the EV market more than anything else (since car makers must offer more low- and zero-emissions new vehicles to avoid penalties).

A growing demand for EVs means a growing need for EV charging infrastructure. As such, installing EV charging stations in homes is becoming an increasingly common request from EV car owners, particularly when they can benefit from solar PV for charging. To support Australians making the switch to EVs, the National Construction Code (NCC) requires more buildings to be ready for EV charging.

How does the building code deal with EV charging?

For builders and developers, your Class 2-9 building projects under NCC 2022 Volume One will now require pre-provisioning the carparks associated with those buildings. This includes the provision of EV charging demand management equipment to service all carparking associated with Class 2 apartments, and a proportion of carpark spaces associated with Class 3 residential buildings and commercial Class 5 to 9 buildings. The Australian Building Code Board (ABCB) has released guidelines on charging precautions for EVs.

NCC 2022 does not require pre-provisioning for Class 1 detached dwellings (or Class 10 garages used as onsite parking), nor does it require the installation of EV chargers in any residential or commercial building. However, it’s expected that future editions of the code will include similar pre-provisioning (cables and conduits, etc) to enable future charging equipment to be installed. 

What do I need to know about EV charging? 

With the increasing electrification of homes, balancing electrical supply is becoming more important. The capacity of the supply will need to be matched to the equipment loads on the building and should consider the future use of EV charging. For example, a home with a single-phase electrical supply is limited in its ability to export unused energy from solar PV and takes longer for EVs to charge (around 10-20km of range obtained per hour with a mode 2 charger). 

A typical EV can charge more than twice as fast at the same amperage with a dedicated sub-circuit or three-phase electrical supply. This provides more capacity both to export power, and additional capacity and flexibility in the choice of EV charging.

Safety recommendations for installing EV chargers

Presently in Australia, there is no national guideline or standard that sets out the installation requirements for EV charging equipment into homes. However, most EV car manufacturers have guidelines and specifications that prescribe recommended measures. 

Standards Australia has commenced work on a new standard to outline installation and supporting mitigation measures. Similarly, the ABCB has produced a broader guideline. However, it’s more applicable for commercial buildings and carparks in multi-residential buildings.

For houses and multi-residential buildings, HIA recommends several simple and practical installation measures for EVs, particularly in enclosed garages. This includes:

• Adding a master-isolation switch to isolate the electrical supply to a charger which avoids the need to interact with the device in the unlikely event of a fault
• Using chargers with RCD protection that have a Regulatory Compliance Mark (RCM) 
• Placing chargers, switches and cables away from the car or swinging doors to avoid damage
• Using baskets for cables when not in use to avoid damage to the cable from its weight
• Locating chargers away from exits or other flammable materials
• Only allowing qualified persons to install electrical supply and mode 3 chargers in accordance with AS/NZS 3000 Appendix P.

Allowing for the installation of EV charging stations into future homes will likely form part of a suite of electrification and decarbonisation measures that will affect Australian housing going forward. 

As we continue on a path toward net-zero buildings, it will no doubt be a hot topic amid various proposed energy and sustainability regulations. HIA will keep an eye on this space and report back to members of any significant developments affecting the residential building industry. 

Understanding domestic EV charging

EVs require a dedicated electrical source to charge the vehicle’s high-voltage battery. Power is supplied as Alternating Current (AC) which is then converted to Direct Current (DC) via an inverter onboard the vehicle. As cars spend most of their time idle, the majority of EV charging occurs in the home from a household supply via a mode 2 or 3 charger.

A mode 2 charger is generally supplied with the vehicle, is portable and provides basic functionality including RCD protection and earth continuity monitoring. The only prerequisite is an accessible domestic 10-amp power point (likely available in any garage).

Mode 3 chargers are faster and require more capacity in the electrical supply. These units generally consist of a wall-mounted panel with an integrated cable or cable plug outlet. These often offer added safety with intelligent controls such as built-in monitoring.

Bi-directional charging is the process whereby an EV charger enables two-way flows both to and from an EV. This can be used to supply electricity back to the grid or another EV. Chargers with this capability are more expensive and less common in both EVs and chargers in Australia, but technology is moving quickly.

First published on 22 November 2023