Service Entrance Demand Load (Standard Method)
NEC Article 220 Standard Method demand-factor walk; recommended service ampacity from the standard ladder.
Example
You enter
- Area (ft²) 2500
- Small appliance circuits 2
- Laundry circuit 1
- Fixed-appliance load (W) 8000
- Fixed-appliance count (≥ 4 → 75% demand) 5
- Range nameplate (W) 12000
- Dryer nameplate (W) 5000
- Largest motor (W) [+25% adder] 1500
- HVAC cooling (W) 6000
- HVAC heating (W) 9000
- Service voltage 240
You get
- Total demand 34525 VA
- Required service A 143.8
- Recommended service 150
Checked against published worked examples from: NFPA.
Details, formula, and sources
Formula or tableStandard Method per NEC 2023 Table 220.45 (general lighting demand factors, 220.42 before 2023: first 3000 VA at 100%, next 117000 VA at 35%, remainder at 25%); 220.53 (fixed appliances 75% where four or more fastened-in-place appliances share the feeder or service); 220.54 (dryer 5000 W or nameplate, whichever is greater); 220.55 (range simplified); 430.24 (largest motor at 125%); 220.60 (HVAC larger of cooling vs. heating). Service A = total_VA / V; recommended service from the NEC 100/125/150/175/200/225/300/400 ladder.
Source and editionNEC 2023 (NFPA 70). Article 220 (Branch-Circuit, Feeder, and Service Load Calculations).
Free accessFree read-only access at nfpa.org/freeaccess.
What governsEstimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
API field namesarea_ft2, small_appliance_circuits, laundry_circuit, fixed_appliances_W, fixed_appliance_count, range_W, dryer_W, largest_motor_W, hvac_cooling_W, hvac_heating_W, service_voltage, total_VA, required_A, recommended_A
- General lighting load density 3 VA per ft² (NEC 2023 220.41 dwelling)NEC 2023
- Small-appliance circuit value 1500 VA per circuit (≥ 2 required)NEC 220.52(A)
- Laundry circuit value 1500 VA (one required)NEC 220.52(B)
- Range demand ≤ 8 kW: 100%; 8-12 kW: 8000 VA; > 12 kW: 8000 + 5% per kW above 12NEC 220.55 simplified
- Service voltage 240 V single-phase split unless user suppliesANSI C84.1 nominal dwelling service