Note: For multi-phase systems, loads are balanced evenly across Phase A, B, and C.

Maximum Demand Calculation Methods ├── 1. Calculation Method (Standard Tables & Diversity) ├── 2. Assessment Method (Operational Data & Logging) └── 3. Measurement Method (Real-time Metering) 1. The Calculation Method (Prescriptive)

| Load Description | Qty | Unit Power (kW) | Total Connected (kW) | Demand Factor (%) | Individual MD (kW) | Diversity Factor | Group MD (kW) | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | Lighting | 1 | 20 | 20 | 100% | 20 | | | | Conveyors | 10 | 5 | 50 | 80% | 40 | | | | Compressors | 2 | 30 | 60 | 50% (largest) | 30 | | | | | | | | | 90 | 0.95 | 85.5 | | Office Load | 1 | 15 | 15 | 90% | 13.5 | 0.85 | 11.5 | | Total System MD (kW) | | | | | | | 97.0 |

Determine the wattage (W) or Volt-Amperes (VA) for every item within each group. Use the manufacturer nameplate data for fixed machinery. For general lighting and sockets, use the standard volt-ampere allocations specified by your local electrical code. Step 3: Apply Diversity Factors

There are two principal approaches to calculating maximum demand, and in practice they are often used together.

The Ultimate Guide to Maximum Demand Calculation in Electrical Systems

Because maximum demand in utility bills is measured in , a low power factor directly increases the apparent power demand. Improving power factor with capacitors reduces kVA and, consequently, demand charges. A plant operating at 0.7 power factor will have a kVA demand that is approximately 43% higher than the same real power consumed at unity power factor.

20 kW connected, demand factor 0.7 → 14 kW

: Collect time-series load data from energy meters, supervisory control and data acquisition (SCADA) systems, or data loggers. Resolution should be at least 1-minute intervals, preferably 15- or 5-second intervals, to capture rapid changes.

Regulatory standards—such as in Australia/New Zealand or the National Electrical Code (NEC) in the United States—provide structured allocation tables. This method categorizes loads (lighting, power outlets, cooking appliances, HVAC) and applies a specific, declining demand percentage or fixed current allowance to each group. The Assessment Method

At its heart, Maximum Demand (MD) is the greatest average load (typically in kW or kVA) that an electrical installation draws during a specific time interval over a billing period. It's not the absolute highest instantaneous current, but the highest sustained demand, usually averaged over a 15, 30, or 60-minute window.

Before diving into the formulas, you must understand the core electrical concepts that govern peak load estimation.

Situation: A two‑storey office with: