Kitchen Island Supply.

And why is any special requirement necessary Mr "Iggins". All types of cables are satisfactory for short periods of being wet. As for depth, I think "whatever" as the circuit will have RCD protection against accidents with the drill, unlike the plumbing! The distance from pipes doesn't matter much as the overall floor temp will be only 20-25C or so, and even close to a pipe not much more.

I would use standard twin with earth cable, in plastic or metal conduit. As the operating temperature is unknown but a bit higher than normal I would use cable one size larger than would otherwise be required.

Possibly some other common type of cable, but again "one size up"

I am not concerned with dampness. The cable will be buried into the downstairs' kitchen floor so armoured may be better as it is better for burying init?

Z.

Bog standard T & E or whatever. How do we ensure we keep it within zones might need some thinking about though

I agree with T&E because it is, well, flat. The water in the pipes may be anything up to 50degC so worth derating the cable. 

At what stage is the install at?

Some wet UFH designers like to lay pipes in the whole kitchen floor, under units and islands, and put the flooring everywhere too. In order to accommodate kitchen redesign in the future, then put slabs of insulation under the kitchen units to keep the contents of the cupboards from getting warm. It makes white goods that sit on the flooring, WMs, DWs, cookers and fridges a bit warm though.

Oh yes. The floor may get very warm I thought. The builders are just at the design stages at present, and no work has been done as yet. The house has a new gas combi boiler. Will the floor pipes get as hot as radiator pipes, or will there be a separate "floor sensor/thermostat"? 

Z. (On behalf of Mr. Iggins)

Edit. Add, I have just found this video. 45 degrees C is quite warm for the underfloor pipes. and the heat may build up near to the cable run.

www.youtube.com/watch

I had assumed a modicum of separation betwixt  pipe and cables so no touching perhaps

Will the floor pipes get as hot as radiator pipes

UFH runs at a lot lower temperature than radiator circuits - mine's set at around 40ºC - compared with 60-80ºC for rad circuits. Where a boiler (or other heat source) can run hotter than the UFH wants, it's usual for the UFH circuit to be fed though a thermostatic blending valve and its own pump (effectively the pump re-cycles the water from its own UFH circuit, only drawing a little of the 'hot' water from the boiler circuit as the through the blending valve as temperature drops). It may be higher than 40ºC under a solid floor if the building isn't well insulated - there should be some design calculations for the UFH which should give you an idea of your particular situation.

or will there be a separate "floor sensor/thermostat"?

Normally each room has its own thermostat, which then control the flow through the UFH pipes in that room via a manifold. In effect similar to having a thermosatic radiator valve, but somewhat better at sensing the real room temperature rather than the temperature right next to the rad.

    - Andy.

I generally use 2.5 or 4.00mm SWA buried direct for kitchen islands. 20A Type B for O/L protection.

Yes I was thinking that S.W.A. is best. Tough, reliable and overall earthed.

Z.