About Electrical Load Schedule & Panel Sizing
Calculate connected electrical wattage, design amperage, and recommended breaker frame sizes per National Electrical Code (NEC) continuous duty standards (125% factor). Add custom branch circuits to verify service panel capacity.
Key Capabilities & Features
- Interactive branch circuit schedule with dynamic equipment addition and removal
- Automatic NEC 125% continuous load derating application for loads operating ≥3 hours
- Computes total connected watts and NEC design amperes
- Recommends standard main circuit breaker amperage (15A to 400A)
- Recommends electrical service entrance panel rating (100A, 200A, 400A)
How to Use Electrical Load Schedule & Panel Sizing
Select Service Voltage
Choose 120V single-phase, 208V commercial, or 240V split-phase.
Add Equipment Circuits
Enter nameplate wattage and flag continuous appliances like EV chargers and HVAC.
Inspect Panel Sizing
Review the total design amperage and recommended minimum service panel rating.
Privacy & In-Browser Execution Guarantee
Building equipment schedules remain completely private on your client device.
Frequently Asked Questions
What is the NEC 125% continuous load rule?
NEC Article 210.20 requires branch circuit overcurrent protective devices (breakers) to be rated not less than 125% of continuous loads (operating 3 hours or more) plus 100% of non-continuous loads.
How do I determine if an appliance is continuous?
Water heaters, EV charging stations, space heaters, and commercial lighting that stay energized continuously for 3 hours or longer are classified as continuous loads.