Free single-family electrical service calculator for InterNACHI members.

The Single Family Electrical Service Size Calculator takes the guesswork completely out of determining the electrical service size requirement.  The Calculator requires no special knowledge of electrical systems or codes.  All you do is make basic observations about the house and fill in the blanks.  The Calculator lets you enter electrical loads in either Amps or Watts.  the required information can almost always be found on the nameplates of appliances and mechanical equipment.

The Calculator will tell the "Demand Load" (a trade term, different from "connected" load), the nearest standard size panel and main breaker, the conductor (wire) size and the conduit size.    

The Calculator's worksheet can be filled out in about three to four minutes and can be included with any inspection in PDF format.      

Features of the Calculator:
-Automatically calculates the total demand load for a residential single family dwelling
- provides the demand load in both volt-amperes and Amperes
- Automatically adds the minimum of small appliance and laundry branch circuits
- Automatically determines the heating and air conditioning demand load
- Determines the standard service panel size for the system
- Determines the service wire gauges in both aluminum and copper
- Calculations are based on the National Electrical Code (optional method)
- NEC section references under each heading