running a cable in underfloor heating

[ExArmy]

a kitchen island needs power to it for a double socket, apparently it has a flex with a plug on it, and you just need to plug it in somewhere. and as it'a an island it would mean pugging a socket in the middle of the floor. at the minute theres a blind of concrete on the floor, there is going to be 100mm insulation, underfloor heating pipes and then a 50mm screed on top. which will get quite hot, so obviously this will derate the cable alot i'm thinking it'd probably be best to run the cable from a FCU on the ring in probably 4mm in conduit to the floor socket but i havent done any calcs yet. how hot does underfloor heating get? will a normal floor socket be alright with the heat?

 

[Guest55]

Use a metal clad socket , will handle heat better and wont get smashed up when fitted to the floor.
floor heating doesnt get that hot so 4mm in conduit should be fine.

 

[Richard]

Why couldn't you go underneath the celotex? You should have minimum heat there and your clear from the pipes and just JB onto the flex for the island.

 

[ExArmy]

well i've had to turn down the job anyway as i can't get it done within the timescale, but at least i know how to do it for next time now!
i was going to run it below the insulation, in theory it'd be pretty cool down there as 75mm insulation(to allow for the notch) is pretty good at "insulating" from the heat, and heat rises anyway. so in theory, if the only factor in derating is the fact that it's buried in thermal insulation for more than half a metre which halfs the CCC, so a 2.5 would be ok at 13.5A?