A continuous load is defined by NEC Article 100 as a load where the maximum current is expected to continue for 3 hours or more. Common continuous loads include commercial lighting circuits, HVAC equipment, and EV charger circuits. For continuous loads, both the conductor and the overcurrent protection device (OCPD) must be sized at 125% of the continuous load current — or at 100% of the load if the breaker is 100% rated. This requirement is separate from any derating for ambient temperature or bundling. For example, a 30A continuous load requires a conductor rated for at least 37.5A (30 × 1.25) and a 40A OCPD minimum (or a 30A OCPD that is 100% rated).
32A continuous load: minimum conductor ampacity = 32 × 1.25 = 40A. NEC 310.16 75°C: 8 AWG copper = 50A. Minimum OCPD: 40A (standard breaker). Selected: 8 AWG copper with 40A breaker.
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