Electric Vehicle Charging Systems

EV charging is a continuous load, so conductors and overcurrent devices are sized at 125%. Later editions add energy-management systems (750.30) so multiple chargers can share a service without an upgrade.

When it applies

Article 625 kicks in the moment you install charging equipment for an electric vehicle, whether it is a simple wall unit in a garage or a bank of chargers at a workplace. The charger gets its own dedicated circuit sized for continuous duty, which means you plan for the full rated current running for hours, not minutes.

Common mistakes

• Sizing the breaker and conductors at the nameplate current instead of adding the continuous-load margin, so the wiring runs hot every night.
• Skipping a disconnecting means where one is required for larger equipment.
• Ignoring load management options and instead upsizing the whole service when a smart load-sharing setup would have handled it.

In the field

On a recent install the panel was already near capacity, so instead of an expensive service upgrade I set up energy management so the charger throttles when the dryer and range are running. The customer got a full-speed charge overnight and never tripped a thing.