EV Charging Infrastructure in Commercial Buildings

NCC 2025 Changed the Rules

NCC 2025 introduced EV charging readiness requirements for the first time. Car parks in new Class 2 through Class 9 buildings must now have dedicated electrical infrastructure for EV charging. This does not mean chargers must be installed. It means the electrical bones of the building must be ready so chargers can be added later without rewiring.

The relevant clause is J9D4 in Section J (Energy Efficiency). It sets out distribution board requirements, cable pathway provisions, and minimum power delivery per circuit. The requirements took effect on 1 May 2024 across most states and territories.

Before NCC 2025, there was no national code requirement for EV infrastructure. Developers who wanted chargers had to plan for them voluntarily. Now it is mandatory. The percentage of spaces that must be EV-ready depends on building class.

• Car parks in Class 2, 3, 5, 6, 7b, 8 and 9 buildings must have dedicated electrical distribution boards for EV charging in each storey of the car park (NCC 2025, J9D4)
• Percentage of spaces that must be EV-ready: 100% for Class 2 (apartments), 10% for Class 5 or 6 (offices and shops), 20% for Class 3, 7b, 8 or 9 buildings (NCC 2025, Table J9D4)
• Each circuit must support an EV charger able to deliver a minimum of 12 kWh during an 8-hour window (11 pm to 7 am for Class 2; 9 am to 5 pm for Class 5 to 9) (NCC 2025, J9D4)
• Distribution boards must include space for individual sub-circuit metering (at least 36 mm of DIN rail per outgoing circuit) (NCC 2025, J9D4)
• A charging control system must be fitted to manage and schedule EV charging in response to total building demand (NCC 2025, J9D4)
• One distribution board is required per 24 EV-ready car park spaces (NCC 2025, Table J9D4)
• The main switchboard must have spare capacity allocated for EV loads (NCC 2025, J9D4)
• Does not apply to standalone Class 7a car park buildings (NCC 2025, J9D4)

• Dedicated EV distribution board sizing and location. One DB per 24 EV-ready spaces, located in or adjacent to the car park. Labelled for EV use only.
• Cable tray or conduit routes from the distribution board to parking bays. These share ceiling space with ventilation ductwork and fire services, so routing matters.
• Load calculations for future EV charger demand. At 7 kW (32 A) per charger, a 50-bay apartment building needs 350 kW of future EV capacity. Diversity factors and load management reduce the peak, but the switchboard must be sized for it.
• Spare capacity allocation on the main switchboard. The incoming supply and transformer must account for full EV build-out, not just day-one loads.
• Metering strategy. Individual metering per bay (common in apartments where owners pay their own power) or bulk metering (common in commercial buildings where the landlord controls charging).
• Charging control system. NCC 2025 requires a system that manages charging schedules based on total building demand. This prevents all chargers running at full power during peak hours.
• Coordination with the mechanical engineer. Car park ventilation design must account for EV battery fires, which produce hydrogen fluoride and other toxic gases different from petrol vehicle exhaust. Cable tray routes must be coordinated with ductwork and sprinkler pipework in the ceiling space.