EV fast-charging station electrical design.

Project overview

A national EV charging operator engaged ASTCAD for the electrical design of 8 fast-charging sites across NSW and VIC. Each site comprised 4 × 350 kW DC fast chargers, an HV transformer upgrade, switchboard, lighting design and SCADA monitoring back to a central NOC.

The challenge

Each site had different utility supply capacities and connection arrangements. Several sites required HV transformer upgrades coordinated with local DNSPs. The operator needed a standardised design package that could be value-engineered to suit each site’s specific supply.

Our approach

• Standardised charger and switchboard design package
• Site-specific supply assessment and upgrade design
• DNSP coordination for transformer upgrades
• Lighting design to AS/NZS 1158 for amenity and security
• SCADA architecture for centralised charger monitoring

Deliverables

• Standard design package (applied to 8 sites)
• Site-specific overlays and connection drawings
• DNSP submission documents per site
• Lighting and CCTV layouts
• SCADA architecture and integration package

Outcome

All 8 sites went live within the planned 11-month rollout. The standardised package reduced engineering time per subsequent site by 60%. The operator has retained ASTCAD on a panel agreement for ongoing network expansion.

How we approach EV charging station electrical design

EV charging station electrical design lives or dies on maximum-demand and fault-level calculations. We start with the charger schedule — the mix of AC and DC fast chargers, their diversity, and future expansion allowance — then size the supply, switchboards, protection and cabling to AS/NZS 3000 and the network operator’s connection requirements. Earthing and touch-voltage design gets particular attention on public sites, and load management systems are documented so site owners can add chargers later without a new consumer mains upgrade. Our drawings coordinate civil conduit routes with the electrical layout so trenching happens once.

Deliverables and standards for EV charging projects

The drawing set typically covers site electrical layout, single line diagrams, switchboard schedules, protection settings and discrimination study results, cable schedules with derating calculations, earthing layout, and signage/labelling drawings for compliance. Everything is issued in DWG and PDF with a transmittal register. We design to AS/NZS 3000, the relevant service and installation rules, and charger manufacturer requirements, and we flag any items needing network operator approval early so applications do not stall the build program.

Key considerations for public charging sites

Public charging infrastructure carries obligations a private car park does not. Accessibility requirements shape bay layout and charger mounting heights; lighting and CCTV conduits should be designed into the same trench plan; and vandal resistance influences equipment selection and cable protection. We also design metering architecture so the site owner can bill accurately from day one, whether through the charge point operator’s platform or embedded network metering. Finally, thermal derating matters more than most expect — DC fast chargers in Australian summer conditions can derate significantly, so switchboard and cable sizing uses realistic ambient assumptions rather than nameplate optimism. Getting these details right at design stage costs a few drawing revisions; getting them wrong costs civil rework.

If you are scoping an EV charging site — a single dual-port installation or a multi-bay fast-charging hub — we can review your charger schedule and site constraints, then quote the electrical design as a fixed package. Early engagement is cheapest: the supply application and civil design both move faster when the electrical demand figures are settled first, and our documentation is written so your electrical contractor can price and build from it without clarification rounds.