Commercial General-Lighting and Receptacle Load (NEC 220.42(A) / 220.47)

Commercial general-lighting and receptacle load, with the NEC demand factors.

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Checked against published worked examples from: NEC 2023 (NFPA 70).

Details, formula, and sources

ScopeComputes the commercial general-lighting load (area x the Table 220.42(A) unit load) plus the general-use receptacle load at 180 VA per strap (220.14(I)) with the 220.47 demand factor (100% of the first 10 kVA, 50% of the remainder), then the total VA and amps. The table unit loads already include the 125% continuous multiplier, so none is added on top; the energy code may set the lighting load and the AHJ governs.

Formula or tablelighting_va = area x unit load (Table 220.42(A)); recep_va = straps x 180 VA (220.14(I)); recep_demand = recep_va <= 10 kVA ? recep_va : 10000 + 0.50 x (recep_va - 10000) (220.47); total = lighting + recep_demand; amps = total / (sqrt(3) x V line-to-line) three-phase, total / V single-phase.

Source and editionCommercial general-lighting and receptacle load, NEC 2023 Table 220.42(A), 220.14(I), and 220.47 (Table 220.12 and 220.44 in 2020 and earlier), by name.

Free accessNEC is free to read at nfpa.org/freeaccess. The Table 220.42(A) unit loads already include the 125% continuous-load multiplier of 210.20(A) (the table footnote), so no second 125% is added; the energy code may set the lighting unit load.

What governsEstimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.

API field namesfloor_area_ft2, unit_load_va_ft2, receptacle_count, supply_v, lighting_va, recep_demand_va, total_va, total_a

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