Guides

What Goes Into an EV Charging Site Plan?

Adding resident EV chargers at an existing apartment community takes more than an electrical permit. Most building departments also want a site plan showing the stalls, accessibility, charger foundations, and signage. Here is what goes into one and where projects tend to get stuck.

By Anthony Sutter, P.E. · Licensed Professional Civil Engineer ·

Why the city wants civil plans

The electrical design gets the power to the chargers, but the building department also reviews where the chargers go: whether enough of the spaces are accessible, whether those spaces and their routes are flat enough, how the chargers are anchored, and how the stalls are striped and signed. On an existing parking lot those questions decide where the chargers can go, so the site plan and the electrical design are developed together.

Accessible EV spaces

CBC Section 11B-228.3 sets how many EV charging spaces must be accessible, based on the total number of chargers, and Section 11B-812 sets how those spaces are designed. Even an installation of one to four chargers generally needs one van-accessible space.

The design requirements that matter most on an existing lot are:

  • Slope. The space and its access aisle can be no steeper than 1:48, about 2 percent, in any direction. Older lots are often steeper, which can mean regrading or choosing different stalls.
  • Reach. The charger’s controls and connector must be within accessible reach ranges from a clear floor space.
  • Route. An accessible route has to connect the space to the building it serves.

Exception 1 to 11B-228.3 covers chargers that are not available to the public and are assigned to a designated vehicle or driver, which can apply when chargers are reserved for specific residents. I prepare the exception request where it fits, but whether it applies is the building official’s decision.

Coordinating with the electrical design

The single-line diagram, load calculations, and panel schedules are prepared by a licensed electrical engineer. The site plan follows their work: the location of the panel and service equipment, the trench route through paving and landscaping, and existing utilities that have to be crossed. Energy management systems allowed by the electrical code can often avoid a service upgrade, which changes how many chargers a site can support and where they go.

Charger foundations and protection

Pedestal chargers with cable-management arms are tall and catch the wind, so the footing is sized for overturning and the anchors for tension and shear. Wheel stops or bollards protect the charger from vehicles. I calculate the footing and detail it on the plans, with the charger manufacturer’s anchorage requirements.

Striping, signage, and the permit checklist

EV spaces are striped and signed, including the tow-away signage required under California Vehicle Code Section 22511 to enforce EV-only parking. California Government Code Section 65850.7 requires cities and counties to offer a streamlined permitting process and checklist for EV charging stations, so I start from the city’s checklist and make sure each item is answered on the plans.

What to send for a quote

  • A site plan or aerial of the parking areas
  • The number of chargers and the charger model
  • Photos of the electrical room or service equipment
  • Whether the chargers will be open to the public or assigned to residents
  • The project address and city

This guide is general information, not engineering advice for a specific site. Requirements vary by city, county, and fire district, so confirm them with the reviewing agency for your project.