domestic multiphase question

[davels]

Any help with this i would be gratefull
Job is like this- 1 phase off a 3 phase header with 100amp bs1361 cutouts. The house is quite big (and old) so is why 3Phase type II headers there even thoough the dno hasnt opened 2 up. From meter goes to Wylex 100amp switchfuse with bs88. From there it runs in swa sub-main to 15way insulated single phase consumer i put in. Clients needs were always pushing it for the single 100amp supply but now he wants leccy shower put in and IMO it tips it over maximum demand even allowing for generus diversity.
So thinking i need to ring dno on a few things and if nyone can give me some idea of there point of view woulld be very helpfull in advance.
1. whats the crack with dno opening up another phase -will they charge extra to do it or charge customer any extra for using 2 phases?
2. if another phase was available does this absolutly mean 2 consumers or is it possible to use 1 big board to do this. Have 2 incomers in same board as theres enough spare capacity for this. or do you have to use a multiphase board fullstop? i mean cus client prefers 1 only.
3. Does 100amp bs1361 cutout and 100amp bs88 switchfuse achieve descrimination?
Thanks for any help you can give me
Dave

 

[Matt Thornton]

if theres too much load for single phase it looks like a 3ph supply & board is on the menu, when he see's the quote he's gonna go white. So in the end it looks like he'll opt for a power shower, so you'll still get some work from it.