Generator Sizing
Continuous and surge wattage from running totals and the largest motor's starting draw.
Example
You enter
- Items name Refrigerator, running watts 700, starting watts 2200, and 2 more
You get
- Continuous 1900
- Surge 3400
- Running (kW) 1.9
- Surge (kW) 3.4
Details, formula, and sources
Required kW = max(starting kVA / surge factor, sum of running loads / efficiency); largest-motor LRA contribution per NEC 430.251(B).
NEC 2023 (NFPA 70). Article 700 / 701 / 702; NEMA MG 1 by name.
Free read-only access at nfpa.org/freeaccess.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: items, running_W, surge_W, running_kW, surge_kW
- Surge tolerance 30% voltage dip on starting (engineering practice)NEMA MG 1 by name