I'm in the process of finishing off an extension to my house and finally getting round to sorting out the electics. The existing consumer unit only has a single spare way, but I'm planning to put four new circuits in the extension - upstairs lights, downstairs lights, ring main and electric shower.
I guess that I could get a bigger consumer unit fitted, but given where it is, and the awkward access to the existing cables I'm reluctant to do that, so I'm inclined to either using the existing spare way to supply a new (4 way) consumer unit, or tee the existing consumer unit tails to supply the second consumer unit. Questions therefore are:
1. Are either of these two solutions acceptable under the regs?
2. If I go for the first one, will I be OK just fitting a 50A MCB - my concern here is that if the shower is in use and there is a reasonably large load on the ring main, then the MCB may trip.
3. If I tee into the consumer unit tail, then I guess that the main fuse will need to be pulled - but what then happens about re-instating the seal?
Before anyone comments - I know that this work is all covered under the building regs and will need to be appropriately certified, but I've done 100% of the extension myself (and have got used to the local building control inspections) and I'm determined to do as much of the electrics as possible. Advice gratefully received..