Maximum demand question

[chris day]

A client contact me as they are getting the supply upgraded to a block of flats and UKPN need a figure adjusted for diversity for each flat.
The original contact didn’t give a crap about the supply capacity.

x6 flats have been refurbished and during this process x6 15kw electric boilers for each flat has been added. (No gas in flats).

The issue I am having is after diversity from the OSG I am getting a crazy number per flat (150a roughly) or maybe I am missing something.

With my calculations I feel I am overkill and a substation will need to be installed, how common are the electric combi boilers as they are a big problem and not accounted for by the original fit out contractors, I am close to telling client they can’t have them and need an alternative as a substation is 100k

UKPN have said you need a sub station installing if each flat consumes 150a... these bloody boilers, I suppose it’s not my problem but I want to feel I am being realistic with my advice atleast.

Each flat DB is the following:
CCT1 Boiler supply 63a
CCT2 Ring 1 32a
CCT3Ring 2 32a
CCT4 lights 1 6a
CCT5 lights 2 6a
CCT6 Oven 40a
CCT 7 Hob 16a

 

[buzzlightyear]

With the advent of low power appliances is there more sense in putting rings on 20A MCB ( mad but just for discussion, using 1.5 T&E)

I get the point why don't they use 1.0mm instead .its is called resistance .don't fight it .the bigger the cable the more flow of current .