EV Load-Management (EVEMS) Diversified Load (NEC 625.42)
The diversified service load of a bank of EV chargers under a NEC 625.42(A) energy management system: without an EVEMS the service carries the SUM of every charger at 125% (forcing an upgrade); with a listed EVEMS the demand is 125% of the aggregate limit it enforces, not the sum. Four 40 A chargers held to 80 A: 200 A sum vs 100 A managed -- 100 A freed, so four chargers land on a panel sized for one.
Formula and source
unmanaged_sum = 1.25 x per_charger x count; managed_demand = evems_limit > 0 ? (setpoint125 ? 1.25 : 1.0) x evems_limit : unmanaged_sum; freed_headroom = unmanaged_sum - managed_demand.
NEC 2023 (NFPA 70). Article 625 (625.42(A) energy management systems) with the 2026 625.48 continuous factor on the EVEMS setpoint.
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