How to Calculate Diversity
There are many ways to apply different electrical diversity factors to different types of electrical loads, fixed equipment or electrical circuits. Calculating diversity is not an exact science since there are multiple varying factors which must be considered when calculating diversity and maximum demand, these factors will vary from premises to premises.
It is also worth considering the life span of the electrical installation as should the way the installation is used change then the diversity factors applied previously may no longer be relevant.
As a very basic example to calculate diversity for a cooker in a dwelling, based on Appendix A of the OSG:
- Cooker = 8kW
- 8kW x 230v = 34.78 Amps
The first 10 Amps + 30% of the remaining load so, 10 Amps + 7.43 Amps = Total (after diversity) 17.43 Amps.
Diversity can be applied to a cooker as it is very unlikely that the oven, grill and all 4 hob rings are going to be heating all at the same time, once the oven or hob ring has reached its target temperature then it will switch itself off until the temperature drops.
Some types are load are not permitted to have diversity to be applied such as electric heaters and showers because it is either on or off.