Diversity

[Rockomuir]

Hello all,

Have a potential 2 flat in the near future which are both tiny 1 bed flat. It consists of:

Cooker 3kw,hob 5kw,3 electric 1kw heaters,7kw shower,2kw under sink heater(not instantaneous) light and 2 rings. After diversity calcs i come to about 70 amps. I still think that this is a bit excessive as the chance of the shower being on with the cooker is limited and everything being used at once do to the fact at most there is going to be two people living there.
I was thinking of 80 amp switch-fuse supply the flat with 16-mm t/e with additional 10 mm g/y. clipped direct. the incoming is a three phase 100 amp supply. What are peoples thoughts on the max demand as i still feel that a 63 amp switch fuse would be more than adequate as most domestic properties i have come across are fine on 60/80 amp.

Thanks

 

[malcolmsanford]

Add the protection devices up and *0.4 that is as near as most for a good way to do it or you could do it as in OSG pg 97 table 1B part 9 in the table.

T+E sub mains, unless you run it surface or try and put it through some earthed conduit, your going to have to RCD protect that with a 30mA one. Not feasible to run SWA?

 

[Rockomuir]

Thanks for the reply,

Swa is not really possible but the T/e would be on a riser and then in a suspended ceiling to the flat so would be concealed over 50 mm from the surface. I thought that this removed the need for rcd protection.

 

[malcolmsanford]

Is the riser surface? But yes if your below 50mm then no need for RCD protection, unless a wall or partion as metalic parts in it's construction.

 

[Rockomuir]

Yea the riser is surface, thanks for the help,