Skip to main content

Sizing Branch Circuits for Continuous & Noncontinuous Load Types

The NEC requires that branch circuits be sized to serve 125% of the continuous load and 100% of the noncontinuous load (NEC 210.20(A)).

Design Master Electrical includes an option to calculate the branch circuit load at 125% of both the continuous and noncontinuous. This is a more conservative approach than what the NEC requires. You can change this setting using the Size breakers to 100% of noncontinuous load ▾ setting in the Circuits, Load Types, and Wire Sizes section of the Options command.

When creating a custom load type using the Custom Load Type: Load Type ▾ setting in the Circuits, Load Types, and Wire Sizes section of the Options command, you can specify whether it should be treated as a continuous or noncontinuous load for branch circuit sizing.

The load types are broken down between continuous and noncontinuous as follows:

Continuous​

  • Lighting
  • Motors (NEC 430.24)
    • Largest Motor
    • Other Motors
    • Cooling, Largest Motor
    • Cooling, Other Motors
    • Heating and Cooling Motor
    • Appliance Motor
  • Continuous
  • Heating (NEC 424.4(B))
  • Appliance, Continuous
note

All motors are considered continuous at the branch circuit level.

Noncontinuous​

  • Receptacles (NEC Handbook Exhibit 220.4)
  • Noncontinuous
  • Kitchen
  • Diverse
  • Small Appliance
  • Laundry
  • Appliance, Noncontinuous
  • Electric Dryer
  • Electric Cooking
  • Marina / Mobile Home / RV