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
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