Dwelling Load Calculations — General Lighting, Small-Appliance, and Laundry (Standard Method)

When you size the electrical service for a home, the code gives you a step-by-step "standard method" so two contractors calculating the same house land on the same number. This lesson covers the first three pieces of that calculation for a dwelling: the general lighting load, the small-appliance branch circuits, and the laundry branch circuit — and how a demand factor then shrinks the total to a realistic number.

Edition note: These values are for the 2025 California Electrical Code (based on the 2023 NEC) — the edition your C-10 exam is built on. Watch out: the 2026 NEC lowers the general lighting figure to 2.0 VA/ft², but that is not your exam edition. Use 3 VA/ft².

1. General lighting load — 3 VA per square foot

The code doesn't make you count every light fixture. Instead, a dwelling's general lighting and general-use receptacle load is figured at a flat 3 volt-amperes (VA) for every square foot of floor area. (CEC 220.41)

How you measure the area (CEC 220.5(C)): use the outside dimensions of the dwelling. Leave out open porches and unfinished areas that can't be adapted for future living space.

⚠️ 2023 code change worth memorizing: Older editions also excluded the garage. The 2023 NEC (carried into the 2025 CEC) removed garages from that exclusion — so garage floor area is now included in the general-lighting square footage. This is a common exam-trap because so much study material still shows the old rule. (CEC 220.5(C))

Example: a 2,000 ft² dwelling → 2,000 × 3 VA = 6,000 VA of general lighting load.