The demand factor is defined as the ratio of the maximum demand of a system (or part of a system) to the total connected load for that part being considered. Different loads have different demand factors. The demand factor is always equal to or less than one.
For example, all lights will probably be on at the same time, so the demand factor for lighting is often taken as unity. It is rare, however, for all motors to run at the same time, and they are probably not running at full power. Therefore, the demand factor for these motors is less than unity. Typical demand factors are listed. These numbers should be tempered by experience.
Local electrical codes may permit conductors with lower ampacity than total connected loads would indicate. The "connected load" would be reduced by the appropriate demand factor and diversity factor when sizing the service entrance conductors.
| MOTORS
|
| INDUCTION FURNACES
| 80
|
| General Purpose
| 30
| ARC FURNACES
| 100
|
| Semi-Continuous Processes
| 60
| LIGHTING
| 100
|
| Continuous Operations
| 90
| ARC WELDERS
| 30
|
| RESISTANCE HEATING
| 80
| RESISTANCE WELDERS
| 20
|
