NEC Article 625: EV Charging Systems
Article 625 of the National Electrical Code covers 'Electric Vehicle Charging System' installations. Key requirements include: equipment must be listed and labeled for EV charging (UL 2594 or UL 2231), circuits must be sized at 125% of continuous load (the '80% rule'), ground-fault protection is required for outdoor installations, and proper labeling must identify the circuit as an EV charger. These aren't suggestions — they're code, and your city inspector will verify compliance.
- •Equipment must be UL-listed for EV charging (UL 2594 or UL 2231)
- •Circuit sizing: 125% of continuous load (80% rule)
- •GFCI protection required for outdoor installations (NEC 2020+)
- •Proper labeling required at panel and charger
- •Disconnecting means required (the breaker serves this function)
- •ChargeWizards installations meet or exceed all NEC requirements
The 80% Rule Explained
The NEC requires that continuous loads (those expected to run for 3+ hours) be sized at 125% of the actual load. This is why a 48A charger requires a 60A circuit (48A × 1.25 = 60A). In practice, electricians often round to standard breaker sizes: a 40A charger uses a 50A breaker, a 48A charger uses a 60A breaker, and a 32A charger uses a 40A breaker. This ensures the breaker doesn't trip during normal operation and provides a safety margin.
- •48A charger → 60A breaker (48 × 1.25 = 60)
- •40A charger → 50A breaker (40 × 1.25 = 50)
- •32A charger → 40A breaker (32 × 1.25 = 40)
- •Prevents nuisance tripping during long charging sessions
- •Provides safety margin for continuous operation
- •Required by NEC Article 625.41
GFCI Protection Requirements
The 2020 NEC requires Ground Fault Circuit Interrupter (GFCI) protection for all outdoor EV charging installations. This is a critical safety feature that detects ground faults and shuts off power within milliseconds, preventing electrocution. Many modern EV chargers have built-in GFCI protection (Tesla Wall Connector, ChargePoint Home Flex). For chargers without built-in GFCI, a GFCI breaker or GFCI receptacle must be installed. California adopted the 2020 NEC with amendments, so GFCI is required for all outdoor residential EV charger installs.
- •GFCI required for all outdoor EV charger installations (NEC 2020+)
- •California has adopted 2020 NEC with GFCI requirement
- •Many chargers have built-in GFCI (Tesla, ChargePoint, JuiceBox)
- •For chargers without GFCI: GFCI breaker or receptacle required
- •GFCI protects against ground faults and electrocution
- •Indoor installations in garages: GFCI typically not required but recommended
Wire Sizing and Conduit Requirements
NEC Table 310.16 specifies wire sizes based on amperage. For copper THHN wire (most common for EV installs): 60A circuit requires 6 AWG, 50A circuit requires 6 AWG, 40A circuit requires 8 AWG, 30A circuit requires 10 AWG. Conduit must be appropriately sized for the wire (typically 3/4" or 1" for EV circuits). Outdoor conduit must be rated for wet locations (PVC Schedule 40 or 80, or EMT with proper fittings). All wiring must be protected from physical damage.
- •60A circuit: 6 AWG copper minimum
- •50A circuit: 6 AWG copper minimum
- •40A circuit: 8 AWG copper minimum
- •30A circuit: 10 AWG copper minimum
- •Outdoor conduit: PVC Schedule 40/80 or protected EMT
- •All wiring must be protected from physical damage
Labeling and Signage
NEC 625.44 requires specific labeling for EV charging circuits. The circuit breaker in your panel must be labeled 'Electric Vehicle Charging' or similar. The charger itself must have a permanent label indicating it's for EV charging. If the charger has a disconnect switch, it must be labeled. These labels aren't just bureaucratic — they tell future homeowners, electricians, and first responders what the circuit is for.
- •Breaker must be labeled 'Electric Vehicle Charging'
- •Charger must have permanent identification label
- •Disconnect switch (if present) must be labeled
- •Labels must be permanent and legible
- •Helps future homeowners and emergency responders
- •Required for permit approval