Which NEC method does this use?

It uses the standard calculation method of NEC Article 220 Part III for dwellings. General lighting is 3 VA per square foot plus the small-appliance and laundry circuits, with a demand factor that takes the first 3000 VA at 100 percent and the remainder at 35 percent.

How is the general lighting load found?

Multiply the living area in square feet by 3 VA, then add two small-appliance circuits at 1500 VA each and one laundry circuit at 1500 VA. This subtotal gets the 100 percent then 35 percent demand factor before being added to the appliance loads.

Why take the larger of heating or air-conditioning?

NEC 220.60 allows omitting the smaller of two non-coincident loads because heating and cooling do not run at the same time. The worksheet includes only the larger of the two, which avoids oversizing the service for loads that never coincide.

Does this size the service conductors?

It gives the calculated service amperes, which is the basis for selecting the service rating. You still size the conductors from the ampacity tables with temperature and termination corrections, and round up to a standard service such as 100, 150, or 200 amps.

Is this acceptable for a permit?

It produces the standard load summary that most building departments expect, but every AHJ has its own form and may require the optional method or extra detail. Use the figures as the calculation basis and transfer them onto the jurisdiction's official worksheet.

Electrical Permit Load Summary Generator

Most building departments want a load summary before they issue a residential electrical permit. This generator follows the NEC Article 220 standard calculation method: it sums general lighting, small-appliance, laundry, and fixed appliance loads, applies the demand factors, takes the larger of heating or cooling, and reports the calculated service amperes against your panel rating.

How it works

The standard dwelling method assembles the loads and applies a demand factor to the general portion:

general lighting  = area_ft² × 3 VA
small appliance   = 2 circuits × 1500 VA = 3000 VA
laundry           = 1 circuit × 1500 VA
general subtotal  = lighting + small appl + laundry
demand applied    = 3000 VA at 100% + remainder at 35%
fixed appliances  = range + dryer + water heater + other (nameplate VA)
hvac              = larger of heating or A/C (220.60, non-coincident)
total VA          = demand applied + fixed appliances + hvac
service amps      = total VA / service voltage

The first 3000 VA of the general subtotal is counted in full, and everything above that is taken at 35 percent, which reflects that not all lighting and receptacle load runs at once.

Example and notes

A 2000 square foot dwelling has 6000 VA of general lighting, plus 3000 VA small-appliance and 1500 VA laundry, for a 10,500 VA general subtotal. Applying the demand factor gives 3000 + (7500 × 0.35) = 5625 VA. Add an 8000 VA range, a 5000 VA dryer, a 4500 VA water heater, and a 6000 VA air conditioner (larger than the heat), for 29,125 VA total. At 240 volts that is about 121 amps, so a 150 amp service is the next standard size. Always transfer the figures onto your jurisdiction’s official permit form.