Special Systems

EV Charging and NEC Article 625

How the code treats electric vehicle charging: continuous load sizing at 125%, individual branch circuits, adjustable chargers and load management. Includes a quick calculator.

By IES team, Innovative Electrical Services (IES), Auburn, CA · Reviewed November 2026 · 3 min read

Key takeaways
  • EV charging counts as a continuous load, so circuits are sized at 125% of the charger’s maximum current.
  • A 48 A charger needs at least a 60 A circuit; a 32 A charger needs at least 40 A.
  • Chargers over 16 A or 120 V generally need their own individual branch circuit.
  • Adjustable chargers and energy management systems can help fit charging on a busy service.

An electric car can draw full power for hours at a time, which is very different from a toaster or a hair dryer. Article 625 of the NEC sets out how EV charging equipment, called EVSE, is supplied and installed.

Charging is a continuous load

The NEC treats a load expected to run at its maximum current for three hours or more as continuous, and the branch circuit and overcurrent device have to be sized at 125% of it. Article 625 says to treat EV charging this way. So:

  • A 48 A charger: 48 × 1.25 = 60 A minimum circuit.
  • A 40 A charger: 50 A minimum.
  • A 32 A charger: 40 A minimum.
Charger draw48 A× 125%60 A48 A × 1.25 = 60 A minimum breaker, with wire to match
EV charging counts as a continuous load, so the circuit is sized at 125% of the charger’s current. A 48 A charger needs at least a 60 A circuit.

Try it

EV circuit size at 125%Enter the charger’s maximum current (from its label or settings).

Gives the minimum breaker rating. Your electrician also checks the wire, the panel load and any energy management system.

Individual branch circuits

Outlets for EV charging rated more than 16 A or more than 120 V generally need an individual branch circuit with no other outlets on it, with some allowances for listed equipment that shares power between chargers. Two chargers in a shared garage can be supplied together when they are designed to split the available current.

Adjustable chargers

Many hardwired chargers can be set to a lower maximum current. The 2023 NEC allows the circuit to be sized to the adjusted setting when the adjustment is restricted (it can’t simply be turned back up by a user) and the nameplate or a label shows the new setting. This is handy when a 60 A circuit isn’t practical but a 40 A one is.

Energy management systems

If a panel is close to full, an energy management system can monitor the service and reduce or pause charging when other big loads are running, so the service isn’t overloaded. The code allows these systems to set the load used in the calculation when they are installed as described. This can avoid a service upgrade.

Other practical points

  • Receptacles installed for EV charging need GFCI protection (625.54), and listed chargers have their own personnel protection built in.
  • Plug-in chargers on a 14-50 receptacle work, but we recommend a hardwired charger: no receptacle to wear out or overheat, built-in shock protection and only three wires. Read why we recommend hardwired over plug-in.
  • Long runs to a detached garage may call for bigger wire because of voltage drop.

For the homeowner side, see can my panel handle an EV charger?

Sources and further reading

  1. Leviton Captain Code (2023 NEC), Article 625 EV charging
  2. Mike Holt, 2023 NEC Article 625 Electric Vehicle Power Transfer System (excerpt)
  3. NFPA 70, National Electrical Code, 2023 edition (free read-only access)

Local rules decide. These articles explain general ideas and point to the code sections we use. They are not legal or engineering advice and don’t replace the code itself. California adopts the NEC with its own amendments, cities and counties can add more, and the local inspector (the AHJ, or authority having jurisdiction) has the final say on any job. Read the code free at NFPA’s free access page.