Can anyone tell me where the value of 1500 VA comes from for the small appliance and laundry calcs. This only works out to 12.5 amps per circuit, but they are 20 amp circuits. I thought it might be some kind of demand factor, but we are already including this figure when we take the lighting demand - thus it is being reduced twice?

If this is some sort of demand, how did it get decided on 1500VA?