How to check if a site has enough power for EV chargers

Start with how much power you need

Add up the power rating of every charger you plan to install. Four 150 kW fast chargers need about 600 kW. Ten Level 2 chargers at 7.2 kW need about 72 kW. That total is the number the electric company cares about.

Many sites start smaller and add chargers later, so it helps to know both your first phase and your full plan.

Find out what the power lines can carry

Some electric companies publish maps that show how much new load each power line can take before it needs an upgrade. These are often called hosting capacity or load capacity maps. California's three big utilities, several New York utilities and the Pepco family of utilities publish them.

Where no map exists, distance is a useful clue: sites close to a substation or high-voltage line are more likely to have power available than sites far from them.

Compare the two numbers

If the spare capacity is bigger than what you need, your project may fit without a grid upgrade. If it's smaller, expect the utility to upgrade equipment, which adds cost and time.

• Small shortfall: usually a new transformer and line work near the site.
• Medium shortfall: often an upgrade to the neighborhood power line.
• Large shortfall: may need new substation capacity, which can take years.

Always confirm with the electric company

Published maps are planning tools and change over time. Before you sign a lease or buy equipment, ask the utility for a load capacity check (sometimes called a pre-application) for your project's size at the exact address.

EV Atlas walks through all of these steps for any US address and shows who to call.