The ratio of the sum of individual maximum demands to the maximum demand of the entire system. Because different loads peak at different times, this factor is usually greater than 1.
: The main service breaker and supply cables must be rated for at least 40 Amps , despite the raw connected load totaling over 55 Amps. Common Pitfalls to Avoid
of total lighting and appliances might only have a maximum demand of at any one time. The Demand Factor is C. Diversity Factor maximum demand calculation
To accurately perform a maximum demand calculation, you must understand several foundational power engineering concepts:
It is not simply the sum of every electrical appliance plugged in at once. It is the peak load that actually occurs during normal operation. Why Calculate Maximum Demand? The ratio of the sum of individual maximum
The sum of the power ratings of all electrical equipment plugged into the system.
Consider a standard domestic apartment with the following connected load profile evaluated under typical international standards (e.g., Institution of Engineering and Technology [IET] guidelines): Load Category Connected Load Standard Demand/Diversity Factor Calculated Demand 66% of total rating Power Outlets 100% of largest ring + 40% of others Electric Cooking Range First 10A (2300W) + 30% of remainder Instant Water Heater 100% of largest appliance Air Conditioning Units 100% of largest + 50% of remainder Total Connected Load 26,500 W Composite System Factor 18,240 W Analysis of the Example: Total Connected Load: 26.5 kW Calculated Maximum Demand: 18.24 kW Common Pitfalls to Avoid of total lighting and
The importance of accurate MD calculation cannot be overstated. For the , the sum of all customers’ maximum demands (diversified demand) determines the required generation, transmission, and distribution capacity. Overestimating MD leads to stranded assets; underestimating leads to brownouts or equipment failure.