Capstone: A Complete Dwelling Service Load Calculation (Standard Method)

This lesson ties Module 1 together. We'll run a full standard-method service calculation for a house, using every rule from the earlier lessons in one continuous example.

The scenario

A 1,500 ft² one-family dwelling with an electric range rated 12 kW, an electric dryer rated 5 kW, and gas heat (no electric heat or A/C).

Step-by-step

1. General lighting (CEC 220.41) — 1,500 ft² × 3 VA/ft² = 4,500 VA

2. Small-appliance + laundry (CEC 220.52) — 2 small-appliance circuits + 1 laundry circuit = 3 × 1,500 = 4,500 VA

3. Combined general load — 4,500 + 4,500 = 9,000 VA

4. Apply general-load demand factors (CEC Table 220.45) — first 3,000 @ 100% = 3,000; remaining 6,000 @ 35% = 2,100 → 5,100 VA

5. Range (CEC Table 220.55, Column C) — one 12 kW range = 8,000 VA