Diversity

[Spearmint]

Thought I'd throw this out there and see what others think. We're working working on a boiler house and storage room separated by an internal wall which is all a separate building to the house. Supply is coming from the house into the new building as a sub main and contains...

2 x 32A MCB ring mains, one for sockets around the inside of the boiler house and the other for the inside of the storage room.

1 x 16A MCB to an immersion of unknown rating (hasn't been ordered yet).

2 x 6A MCB - one for the lighting for both rooms and the other is for the boiler + stats etc.

...all this from a 40A incomer (I'm unsure what the house supply is, presuming 100A).

I'm not part of the CU install, just had a nosy on how the others we're getting on but tried practicing working out diversity after getting a good look at the DB and I work it out to be over the 40A on the incomer.

RFCs: 32A @ 100% + 32A @ 40% = 32A + 12.8A = 44.8A

Have to assume full 16A for the immersion as it isn't on site yet, no diversity allowed so: 44.8A + 16A = 60.8A so far.

Lights: 6 x 100W = 600W / 230V = 2.6A x 66% = 1.7A - 62.5A so far.

Boiler: Unknown load, all controls though so barely anything I imagine, have left this out.

So even after leaving the boiler circuit out I'm at 62.5A on a 40A incomer.

I'm I missing something? Surely this can't be right?

 

[GLENNSPARK]

So all the earache you gave me was worth it, Glenn.

Did you do an averaged KWHr reading? Hope you did because that would blow holes in any diversity calculations.

well i had gone down with the power quality analyser to do just that....but found out i couldn`t get the CT ring into the dis-board enough to get an accurate reading (conductor to be a min of 25mm from edge of CT ring)...so that was a no goer....

went with the clamp as best i could do....but there will be other opportunities to get the power analyser out....