Advice needed. Separating a floor level to an independent supply

geminidawn

I'm looking to separate the top floor of an old house and turn it into a "Granny Flat". Probably for now I'll let it feed off of my mains but as the project develops I'd like it to have it's own independent supply.
The problem lies in the space in between, running the cables for the sockets under the top floor which are in close proximity to the lower floor lighting circut.
I was told that if they were to become two seperate supplies then they would have to be armoured and as you know amoured cable is not cheap, also if anything were to go wrong in the future it would mean access to the wiring would disturb both residences.
A friend of mine suggested that for the "Granny Flat" why not have both lighting and sockets running down from the ceiling. There may be a bit of chasing to do but all wiring would be self contained and accessable through the attic. Is this acceptable practice or would this be frowned upon?

davelerave

physically separating the cabling for the granny flat ie:dropping the wires down from attic would be the preferred way of wiring it .armoured cable wouldn't normally be neccessary for domestic unless it's a steel cabinet.there'll be a separate metered supply needed anyway to avail of the cheaper rate