How to Calculate Electrical Load and Demand Factor for Factory Projects
Learn how to calculate electrical load, demand factor, and transformer capacity for industrial projects. A practical guide for accurate RFQ preparation.
Step 1: List all electrical equipment
Start with a complete equipment list: motors, heaters, lighting, HVAC, elevators, and process equipment.
For each item, note: rated power (kW), quantity, operating mode (continuous/intermittent), and power factor (if known).
Step 2: Apply demand factors
Demand factor = actual load / connected load. It accounts for the fact that not all equipment runs at full load simultaneously.
Typical demand factors: motors 0.6-0.8, lighting 0.9, HVAC 0.7-0.85. Check local standards or engineering handbooks for your industry.
Step 3: Calculate total load and power factor correction
Sum all diversified loads. If power factor is low (<0.9), add capacitor banks to improve it.
This reduces reactive power, improves voltage quality, and may reduce transformer capacity requirement.
Step 4: Select transformer capacity
Transformer capacity (kVA) = Total load (kW) / (Power factor × Load factor).
Add 20-30% margin for future expansion. Common sizes: 500kVA, 800kVA, 1000kVA, 1250kVA, 1600kVA, 2000kVA, 2500kVA.
Provide this data in RFQ
Share: total connected load, calculated demand load, desired power factor, load curve (if available), and future expansion plan.
This helps suppliers recommend optimal equipment configuration and avoid over/under-sizing.