Ventilation for indoor EV charging
No mechanical ventilation is needed for indoor EV charging when the equipment is listed for indoor charging without ventilation. Where it is listed for vehicles that need ventilation, a permanent supply-and-exhaust system to the outdoors is required.
What the code requires
Section 625.52 decides whether charging an EV in an indoor enclosed space needs mechanical ventilation. No mechanical ventilation is required where electric vehicle storage batteries are used, or where the charging equipment is listed for indoor charging without ventilation.
Where the equipment is listed for charging vehicles that need ventilation indoors, permanently installed mechanical ventilation is required. It must include both supply and exhaust, drawing air from and venting directly to the outdoors. Positive-pressure systems are allowed only in charging buildings or areas specifically designed and approved for them.
The required airflow is set by one of the methods in 625.52(B)(1) through (B)(4). One uses tables that give cubic feet per minute, or cubic meters per minute, for the number of vehicles that can charge at one time. The ventilation must be electrically interlocked with the charging equipment so it stays on for the entire charging cycle.
On the job
- Check the charger's listing and markings for indoor charging without ventilation. If it isn't listed that way, the ventilation rules in 625.52(B) apply.
- Where ventilation is required, it must be a permanently installed supply-and-exhaust system, not a temporary fan.
In California
The State Fire Marshal's rulemaking for the 2025 California Electrical Code carries forward its amendments to 625.52, deleting 625.52(B) and amending 625.52(C). The state's code text still prints 625.52(B), so confirm with your building department which version applies to your building.
Related sections
- NEC 625.1.1: California EV-ready rules for new construction
- NEC 625.40: Dedicated circuits for EV chargers
- NEC 625.42: EV charger ratings and load management
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