Electrical load diversity factor is a ratio representing the sum of the individual maximum demands for each part or parts of the system to the maximum demand of the entire system or parts of the system. Another factor that designers consider is demand factor.
Demand factor is a ratio of the sums of maximum demand on a system to the total load on the system. Sometimes designers confuse the terms "demand factor" and "diversity factor."
In electrical design, diversity factor can be described by considering two buildings which have the same maximum demand but the demand is needed at different intervals of time. When the power is supplied by the same feeder, the demand is less than the sum of the two demands. Diversity factors have been designed for main feeders that supply power to multiple feeders which are typically 1.10 to 1.50 for lighting and 1.50 to 2.00 for power and lighting.
As an example, one can think of a feeder that supplies five users with the following load conditions: On Monday, the first person reached a maximum demand of 100 amps; on Tuesday the second user needs 95 amps; on Wednesday user three uses 85 amps; on Thursday user four needs 75 amps; and on Friday user five uses 65 amps. The feeders max demand is 250 amps. The diversity factor would be the sum of the demands divided by the maximum demand of the feeder and then multiplied by 100. In this instance 420 amps divided by 250 is 1.68 which when multiplied by 100 makes it 168%