02 Jul 2020

Masterspec's new generic section, 7765 Electric Vehicle (EV) Charging Stations, responds to increasing EV ownership and NZTA's coordination of NZ's national network of public EV charging stations.

At time of writing, NZBC G9 references the old version of AS/NZS 3000:2007 (the Australian and NZ Wiring Rules), which predates widespread adoption of EV technologies. The latest version, AS/NZS 3000:2018 Electrical Installations, includes EV charging, but is not referenced in NZBC.

AS/NZS 3000:2018 categorises four modes of EV charging: Mode 1 is redundant, so not covered in our new Masterspec section, Mode 2 is limited to domestic charging of small-capacity EV batteries, Modes 3 and 4 are significantly safer with much faster charging speed, thus recommended in NZTA's nationwide network of public charging infrastructure.

Modes 2 and 3 charge the EV with AC voltage, but are very different in appearance - Mode 2 is a standard 240 V AC socket outlet, Mode 3 is an enclosed unit, wall or pedestal mounted, often with a hard-wired charging cable. Modes 3 and 4 may look similar, but they perform very differently: Mode 3 (fast charge) is an AC charger with up to 22kW output. Mode 4 is intrinsically the fastest charger as it outputs DC voltage to the EV at rates of up to 50kW, with 175kW -400kW models on the horizon. For this reason, Mode 4 is most preferred for public charging. Note that some EV's are limited to AC or DC charging.

Infrastructure upgrades should be considered when integrating Modes 2 - 4 into existing buildings with single phase 240 Volt connections: AS/NZS 3000:2018 recommends installing a Load Management System (LMS) and/or upgrading the mains supply to 2 or 3-phase. LMS prevent power black-outs during peak electricity demand by monitoring and prioritising electricity load to the building, while varying the remaining charge to the EV(s).

NZTA are standardising Mode 3 and 4 public EV installations across NZ, including types of socket connectors/outlets that plug into the EV. A short video on NZTA's website called EVRoam explains their intent. NZTA's weblinks for public payment systems, signage, and telecommunications protocol are referenced in Masterspec's new EV section.

Preview the new work section here