What Does EV Charging Infrastructure Design Require?

EV charging electrical design covers load calculations for the charger array, service capacity verification, load management strategy, power distribution to the charging locations, and utility coordination. The key engineering decision is how much simultaneous charging the service can support — managed charging lets more chargers share limited capacity. The design also addresses the code's EV charging requirements, accessible charging space layout, and metering for cost recovery. Owners usually come to me with a charger count in mind — 'we want twenty chargers' — and my first job is translating that into electrical reality. The number of chargers is a site planning decision; the number of chargers that can run at full power simultaneously is an electrical engineering decision. Managed charging bridges the two, and the design documents exactly how.

The load calculation starts with the chargers: Level 2 commercial chargers are typically in the 7 to 19 kW range each, and DC fast chargers are an order of magnitude larger — the charger mix sets the scale of the problem. I apply demand factors reflecting realistic simultaneous use (not every charger peaks at once) and layer load management controls that cap total demand, then check the result against the service capacity. Where the service is short, the options are managed charging, a service upgrade, or a phased approach that installs conduit and capacity for future chargers now. The utility is a stakeholder from the start: service upgrade timelines, transformer capacity, rate structures for EV charging, and any utility-side requirements all affect the design and the economics. I also design the metering architecture — whether the owner absorbs the charging cost, bills tenants, or uses a third-party network — because the metering points have to be in the distribution design, not added later.

The distribution design runs power from the service to the parking area: new panels or switchboards where needed, feeder sizing with voltage drop checked over the long parking-lot runs, conduit routing (often trenched through existing pavement, which is a civil coordination item), and disconnects at the chargers per code. Charger placement gets laid out with the striping plan — pedestal versus wall-mount, protection bollards where vehicles could strike equipment, lighting for the charging area, and the accessible spaces with their specific dimensional and signage requirements. Code compliance covers the electrical code's EV charging provisions — overcurrent protection, disconnecting means, ventilation where required for certain battery types — plus local amendments that increasingly mandate EV-ready or EV-installed parking ratios in new construction and major renovations. In California, the 2025 California Energy Code (2025 Standards), effective January 1, 2026, continues the state's push on EV infrastructure requirements. I design to what's adopted in the jurisdiction, and I future-proof the conduit infrastructure because charger counts only go up.

• Load calculation and service capacity verification — the feasibility gate
• Managed charging strategy to maximize chargers on available capacity
• Distribution design: panels, feeders, trenching, disconnects, metering
• Accessible charging space layout per accessibility standards
• Utility coordination and code-mandated EV-ready parking ratios