Scenario: A packaging plant with:

Step 1: Categorize and Apply Demand Factors

Step 2: Sum the Preliminary MD Total = 40 + 30 + 20 + 15 + 4.15 = 109.15 kW

Step 3: Apply Diversity Between Groups If all equipment operates simultaneously in the 15-min window, diversity = 1.0. However, if the welding machine runs only when conveyors idle? Then diversity = 0.9. Let's assume simultaneous peaks. Final MD = 109.15 kW

Step 4: Convert to kVA (if utility charges on apparent power) Assume measured PF = 0.85 [ MD_kVA = \frac109.150.85 = 128.4 \text kVA ]

Maximum Demand (MD) calculation is the backbone of electrical installation design. It determines the size of switchboards, main cables, transformers, and utility service fees. While the theory is straightforward (avoiding the summation of nameplate ratings), the practical execution is where most engineers either save millions or create hazardous bottlenecks. After testing three major software suites and manual methods against real-world buildings, here is my detailed review.

A 20 HP motor (15 kW nameplate) may only draw 10 kW under normal load. Use actual operating data or efficiency curves. Basing MD on nameplates leads to gross overestimation.