This tool calculates the total electrical load for residential and commercial buildings. It applies demand factor and diversity factor to determine the actual load, and recommends circuit breaker size and cable size. Essential for electrical design and safety compliance.
📐 Load Calculation Formulas
Total Connected Load: Σ (Qty × Wattage) Demand Load: Connected Load × Demand Factor Diversity Load: Demand Load × Diversity Factor Current (A): I = (Load × 1000) / V Breaker Size: I × 1.25 (125% rule)
📊 Typical Demand Factors
Building Type
Demand Factor
Diversity Factor
Residential (Small)
70-80%
85-95%
Residential (Large)
60-70%
80-90%
Commercial Office
65-75%
80-85%
Retail Store
70-80%
75-85%
Industrial
75-85%
70-80%
❓ Frequently Asked Questions
How to calculate electrical load for a house? ▼
Add wattage of all appliances, apply demand factor (70-80%), and diversity factor (85-95%). This calculator does this automatically.
What is demand factor? ▼
Demand factor is the ratio of maximum demand to total connected load. Not all appliances run at full capacity simultaneously.
What is diversity factor? ▼
Diversity factor accounts for the fact that all loads don't operate at the same time. It reduces the total load for sizing purposes.
How to size a circuit breaker? ▼
Breaker size = Load Current × 1.25. Select the next standard size above this value.
What is the difference between connected load and demand load? ▼
Connected load is the sum of all appliance ratings. Demand load is the actual load after applying demand and diversity factors.