diversity factor for students accommodation buildings


i need help to determine the diversity factor for my project
which consists of 9 building as student accommodation buildings feeded from one source
each building contains 4 floor , each floor contains student rooms (1 single phase panel for each room)
so what is the suitable diversity factor i should take in consideration for the sub main panel in each floor
and what is the suitable diversity factor i should take in consideration for the main distribution panel in every building
and lastly what is the diversity factor should i count for the main distribution board for all buildings?

charlie b

Staff member
Seattle, WA
First of all, welcome to the forum. Secondly, let’s talk in terms of “demand factor,” rather than “diversity factor.” It’s a better fit for your question. Third, we don’t assign demand factors for the number of panels, the number of floors, the number of buildings, or anything of that nature. We add up the various types of loads, some of which have demand factors available for our use.

For example, since you are not dealing with a “dwelling unit” installation (or so I surmise from your description), you should be able to take advantage of the lighting demand factors in Table 220.42 and the receptacle demand factors in Table 220.44. Let’s talk about receptacles. The panel that serves an individual student room is unlikely to have more than 10 KVA of receptacle load. So you would have to include that load at 100%, when you calculate the load on that panel. However, depending on how many student rooms are on a floor, the sub main panel (your term) on that floor might serve more than 10 KVA of receptacle load. In that case, when you calculate the load for that panel, you take 100% of the first 10 KVA and 50% of the remainder. Then, when you calculate the main distribution panel for the building, you only count the first 10 KVA of the entire building’s receptacle load, and 50% of the remainder. This allows you a significant reduction. That is because you are saving 5 KVA from the top three floors (i.e., you take each floor above the first floor at 50%, rather than including the first 10 KVA on each floor). You get to do this again when you calculate the load for the 9 buildings.

I don’t know if I made that clear. Essentially, when you calculate the load at each location (main panel, sub panel, branch panel, etc.), you look at all the load served from that location, then take the demand factor on that entire load.


Senior Member
London, England
Are you designing according to the NEC ? or according to the UK IET regulations ?
The location given is Egypt, which MIGHT have more in common with UK practice than American practice.
The terms "diversity" and "submain" might suggest UK influence.