By performing a maximum demand calculation, the design engineer can size the main incoming cable and protective switchgear for an 18.24 kW load instead of a 26.5 kW load. This saves significantly on material costs for copper cabling and distribution boards while maintaining safety margins. 5. Regulatory Variations and Global Standards

Diversity accounts for the fact that you rarely run every light, the oven, the electric shower, and the EV charger at the exact same moment. Step-by-Step Calculation (The "Rule of Thumb" Method)

The sum of the power ratings (in Watts or Amps) of all electrical points in the building.

By mastering maximum demand calculation, you transform from a passive bill-payer to an active energy manager. The savings – often 20–40% on the demand portion of your bill – go straight to the bottom line.

There isn't just one way to calculate maximum demand, and the correct approach depends heavily on whether you're designing a new system or assessing an existing one. The four main methods are:

is the process of estimating the highest amount of electrical power a building or installation will draw at any single point in time.

The ratio of maximum demand to the total connected load. It is always expressed as a value between 0 and 1 (or 0% to 100%).

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

This method involves listing all connected loads and applying demand factors based on experience or regulatory standards (e.g., NEC or AS/NZS 3000).