Residential Service Load Calculator
Properly size a new electrical service for a house or building.
Which method should I use?
- Standard (NEC 220 Part III): The default method. Always allowed for any dwelling unit.
- Optional (NEC 220.82): Permitted only if the service is 100 Amps or greater. Often results in a smaller required service size.
1General Information
2Small Appliance & Laundry
Min 2 required (NEC 210.11(C)(1))
Min 1 required (NEC 210.11(C)(2))
3Major Appliances
NEC Table 220.55 applied
Min 5000 VA applied
Non-coincident load (smaller of AC/Heat) omitted (NEC 220.60)
4Fixed Appliances
Dishwasher, Disposal, Water Heater, etc.
No fixed appliances added.
Service Load
Recommendation
Based on the calculated load of -:
Popular load calculator Configurations
Service Load Calculation
NEC Article 220 Part III
Article 220 Part III governs the Standard Method for feeder and service load calculations. It defines how to sum up various building loads and what percentages (demand factors) can be applied to reduce the total.
Frequently Asked Questions
What is the standard service size for a house?
Most modern homes require a minimum 200A service. Smaller or older homes may have 100A, while large luxury homes often require 400A or more.
How do I calculate square footage for electrical load?
Use the outside dimensions of the dwelling. Do not include open porches, garages, or unfinished basements unless they are adaptable for future use.
Does a kitchen island need a dedicated circuit?
Yes. Kitchens require at least two 20A Small Appliance Branch Circuits. The island receptacles must be served by one of these or a separate individual branch circuit.