Circuits to kitchen island under (wet) under floor heating

[Octopus]

Pretty much as the title says - can anyone point me in the direction of guidance what distance I should allow between under floor heating and 2 x cables to an island in a new kitchen.

Thanks

 

[telectrix]

assuming the floor is going to be insulated below the heating pipes, cables fixed below insulation should be OK.

 

[Octopus]

^^ its an existing floor so the builder wants to "remove" as little as possible of the existing floor.

So direct to the floor is Ok?

 

[Richard Burns]

Overall installing cables above underfloor heating is not a good idea. Installing them in ducting under the heat mat and under the heat mat floor insulation is a much better idea. However this does not seem to be an option in your case.
The maximum surface temperature for underfloor heating is about 35°C so a cable should be able to withstand that indefinitely, you would just need to derate the cable for the ambient temperature, however removing some of the floor to get the cables closer to the heat source does not sound good; would it be possible to overlay another floor surface and allow ventilation to the cables.

 

[Octopus]

^^ I think you misunderstood my ill thought out response!

So laying the cables in a channel cut in the floor directly attached to the floor is OK then? (with the under floor heating above them..)

 

[SJD]

Maybe cut a channel in the floor (or perhaps have the builder cut the channel), and put the cables in flexi conduit in this channel. And have the channel deep enough so there is a significant gap before the heating pipes cross the cable (that gets filled in). But I guess it depends on the floor thickness, cutting the channel might well cut into the insulation below anyway!

 

[Octopus]

Its a 1970's house so I doubt there will be any insulation in the floor!

 

[Richard Burns]

^^ I think you misunderstood my ill thought out response!

So laying the cables in a channel cut in the floor directly attached to the floor is OK then? (with the under floor heating above them..)

Yes, I misunderstood and did not read the title of the thread.
So long as the cables are well below the level of the heating then they should be fine.
If there is no insulation for the heating then they will be wasting a lot of heat warming the ground below, but presumably it has been fine for 40 years, and I might think about putting insulation above (but not on) the cables to limit thermal conductance down to the cables. Ducting or conduit helps (a bit) if you ever have to remove the cables at a later date.

 

[Dave OCD]

As an added precaution you could maybe use 90 degree rated 2.5mm flex for the underfloor bit.

 

[Toneyz]

^^ its an existing floor so the builder wants to "remove" as little as possible of the existing floor.

So direct to the floor is Ok?

here we go the builder wants to do little as possible not what is the correct and right way to do the job that as Telectrix said was the way to do it.

 

[Octopus]

here we go the builder wants to do little as possible not what is the correct and right way to do the job that as Telectrix said was the way to do it.

They all want to do the minimum.....