EV Charger Site Selection and Electrical Planning Checklist for CPOs

Most charger projects that run late were not delayed by hardware. They were delayed by a transformer that had no headroom, a trench route nobody surveyed, or a permit filed after the concrete was poured.

Site selection for EV charging fails in a predictable way. The hardware arrives on schedule, the electrical connection does not, and the site sits dark for months while the utility processes an application. The fix is not more diligence during installation, it is collecting the right field data before the design is drawn.

This checklist runs through the physical layout, the electrical capacity questions, the civil works, and the permits that have to start early. It is written for the person who has to sign off on the site, not for the installer who arrives afterwards.

Bay Layout and Traffic Flow

Start with how vehicles actually move through the site, not with where the electrical room is. A perfectly sized charger in a bay no driver can reverse into is a dead asset, and the cost of fixing layout later is a new concrete pour.

• Bay dimensions: check that the stall depth and width accommodate the largest vehicle likely to use the site, including vans and light trucks, not just passenger cars
• Maneuvering space: a driver should be able to enter and leave the bay without a multi-point turn, and without crossing a pedestrian route
• Enclosure clearance: door swing, cable reach, and service access space in front of each cabinet, plus the clearance the manufacturer specifies for cooling airflow
• Signage and queuing: define where a vehicle waits if the bay is occupied, so a queue does not block the site entrance
• Accessible bays: locate at least one charger on an accessible route with the correct transfer space, and keep the connector height within reach from a wheelchair

Collect This Site Data Before Design Starts

The table below is the minimum dataset an electrical designer needs. Every item on it has delayed a real project at some point, and every one is cheap to collect in a single site visit.

Transformer Headroom and Service Capacity

Ask one question first: how much spare capacity exists at the point of connection during the site peak, not at average load. For a depot or a retail site, the peak is usually a weekday morning or an evening retail rush. A transformer at 80 percent loaded during that window has little room for a 150 kW cabinet, regardless of what the nameplate says.

Where headroom is thin, load management can defer or avoid a service upgrade. A site controller measures the incoming supply and limits charger output so site demand never exceeds a configured ceiling. That turns a hard electrical constraint into a scheduling problem, and it is far cheaper than a transformer replacement. The mechanics are covered in load balancing and dynamic power sharing.

Where headroom is genuinely absent, the project changes shape. A new transformer and medium voltage connection bring a utility application, a design review, and a lead time measured in months. Treat that as a project milestone, not a procurement detail.

Incoming Supply, Simultaneity, and Diversity

The installed capacity of a charger bank and the demand it places on the supply are different numbers. Diversity factors reflect the reality that not every vehicle draws full power at the same moment, and they are the single most abused assumption in charging design.

For AC bays, a diversity factor in the range of 0.4 to 0.6 is common where sessions are long and overlapping, and lower where vehicles are parked all day. For DC, diversity near 1.0 is the safe assumption on a highway corridor, because a queue of drivers each want the maximum rate. Where the supply cannot support nameplate sum, the design must either throttle in software or accept a queue, and that decision belongs in the specification, not in a commissioning workaround.

Cable Route, Length, and Voltage Drop

Cable is priced by the meter and by the cross section, and the cross section grows with distance. A run that is twice as long costs more than twice as much, because a larger conductor is needed to hold voltage drop within limits. Measure the route on site, including the vertical risers, the crossing under any roadway, and the slack needed at both ends.

Confirm whether the route crosses a public highway, a railway, or a third party parcel, because each crossing brings its own permit and its own lead time. A duct bank installed during initial civil works costs a fraction of one cut into finished paving later, so oversize the ducts on the first pass.

Grounding, Lightning, Drainage, and Foundations

These four items are invisible in a product datasheet and account for a disproportionate share of field problems. They belong in the civil scope from the start.

• Grounding: confirm the electrode resistance and bond the cabinet, the foundation steel, and any canopy structure to a single system per the applicable code
• Lightning and surge: an exposed lot with overhead supply lines needs surge protection at the service entrance and at the charger, not only at one end
• Drainage: raise the cabinet base above the surrounding surface, slope water away, and never place a cabinet at the low point of a lot
• Foundation: a concrete pad on a compacted subbase is normal for a floor-standing unit, while wall boxes need a structural wall and a mounting height that matches the cable reach

For a floor-standing unit such as the XNYZY08 DC fast charging station or a four-gun DC cabinet, the manufacturer publishes a foundation drawing. Use it, and have the civil contractor confirm it against the actual soil conditions. A split configuration adds its own constraint, because the main cabinet and its dispensers have a fixed maximum cable run between them.

Lighting, Security, and Accessibility

Charging happens after dark more often than not, and a poorly lit bay is both a safety issue and a utilization issue. Drivers avoid sites that feel unsafe, and the revenue impact shows up before any incident does.

• Lighting levels at the bay and along the pedestrian route, checked at night rather than assumed from a photometric plan
• Camera coverage of the bays and the payment interface, with recording retention that satisfies local privacy rules
• Emergency call or assistance provision where the site is unstaffed and remote
• Accessible route from an accessible parking space to the charging bay, kept clear of the cable management hardware

Signage, Shading, and Driver Wayfinding

Wayfinding is operational infrastructure. A driver who cannot find the charger does not use it, and a driver who finds a bay blocked by a parked non-charging vehicle will not return. Plan entry signage at the site entrance, directional signage at each decision point, and clear bay markings that state the restriction and the hours it applies.

Shading matters in hot climates for a practical reason. Cabinets derate output at high ambient temperature, and a canopy reduces both the derating and the thermal stress on the electronics. Where a canopy is not feasible, leave space for airflow and check the manufacturer derating curve against the local design temperature.

Permits and Approvals to Start Early

The approval chain is usually longer than the construction itself. Start it as soon as the site is shortlisted, in parallel with the equipment decision.

• Utility connection application: filed with the site load data, and often the longest single item on the schedule
• Electrical permit and inspection: required for the service work and the charger circuits in most jurisdictions
• Building or development consent: triggered by a canopy, a new foundation, a change of land use, or tree removal
• Highway or crossing permit: required where the cable route crosses a public road or a public footway
• Signage consent: separate approval in many municipalities, and commonly overlooked until the signs are ordered

Regulation is also tightening on what the station must provide. In the EU, Regulation 2023/1804 sets requirements on payment options, pricing transparency, and data availability that affect both the hardware choice and the site design. Check the current text for the market you are building in, and confirm with the local authority how it is being applied.

Budget the whole chain, not just the hardware. A deployment cost breakdown usually shows civil works, connection, and compliance well above the charger price, which is why a site that fails on electrical capacity is rarely worth rescuing.