Why average? A motor starting up might draw 600A for 2 seconds, but that doesn't melt the cables. The 15-minute average is what heats the transformer. Why does it matter? Utilities size their transformers for your MD. If you have a 5-minute spike once a month, you are paying for infrastructure you use 0.01% of the time. You cannot simply add up the nameplate ratings of all breakers. That is Connected Load , not Maximum Demand. Diversity saves you.
In the world of electrical engineering and facility management, Maximum Demand (MD) is a critical metric. It isn't just about keeping the lights on; it directly impacts your capital expenditure (cable/transformer sizing) and operational expenditure (electricity bills). maximum demand calculator
Where is the Demand Factor (or Diversity Factor). Standard Demand Factors (Reference Guide) | Load Type | Typical Demand Factor | Notes | | :--- | :--- | :--- | | Lighting (Office) | 0.75 – 0.90 | Fluorescent/LED | | Lighting (Warehouse) | 0.95 – 1.00 | High bay, always on | | General Power Outlets | 0.10 – 0.50 | Varies heavily by occupancy | | HVAC (Cooling) | 1.00 | Worst-case summer day | | HVAC (Heating) | 0.80 – 1.00 | Electric heat is high demand | | Lifts / Elevators | 0.40 – 0.60 | Largest motor only | | Motors (Continuous) | 1.00 | Pumps, compressors | | Motors (Intermittent) | 0.40 – 0.60 | Conveyors, cranes | | Kitchen Equipment | 0.40 – 0.70 | Not all used at once | The "Pro" Calculator Tool (Manual Method) If you don't have a power analyzer, use this systematic approach to estimate your MD. Why average