Code reference · NEC 220.12; 220.52; Table 220.45; Table 220.55 Col C; 220.54; 220.82
What size electrical service for a 1800 ft² house? (NEC 220 worked)
Standard method (NEC 220 Part III) for a 1800 ft² dwelling with a 12 kW range, 5 kVA dryer, water heater, dishwasher, and disposal: general lighting 1800 × 3 VA = 5400 VA, plus two small-appliance circuits (3000 VA) and laundry (1500 VA) gives 9900 VA gross — which Table 220.45 demand factors reduce to 5415 VA (first 3,000 at 100%, remainder at 35%).
Add the range at its Column C demand (8000 VA, Table 220.55), the dryer (5000 VA, 220.54), and fixed appliances (6500 VA): total 24915 VA ÷ 240 V = 103.81 A calculated load. A 125 A service covers it.
Add a 48 A Level-2 EV charger (continuous, so it enters the calculation at 60 A / 14400 VA) and the calculated load becomes 163.81 A — pushing the service from 125 A to 200 A. This is why EV-ready panel planning matters, and why 625.42(A) load management is often cheaper than a service upgrade. The optional method (220.82) usually yields a lower number for all-electric homes — worth running both.
Run the numbers yourself
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