Ducting / conduit in concrete floor

[grumpyjohn01]

Am quoting to wire kitchen in a very old farmhouse (high end, very 'beamy' with fragile walls ceilings etc) and am proposing to wire under the new concrete floor slab which is being laid. Having read previous posts on the subject, consensus seems to be to use good quality PVC conduit. Thinking about it though whichever system I use (rigid PVC, Kopex etc) can't think any of them would be rewireable as conduit boxes etc would be inaccessible or kopex bends too tight etc etc ..so does anybody have any tips on products / systems that might be best? or experience of this sort of thing? Thanks in advance John

 

[ChrisElectrical88]

There are several underfloor trunking systems available. We rewired some science blocks a few years ago and used a reinforced metal trunking to wire the island desks. Galv condiut would be my first choice though, depends on how may bends you have in it though.

 

[telectrix]

or use plastic coated MICC. you'll be retired before it needs rewiring.

 

[ChrisElectrical88]

or use plastic coated MICC. you'll be retired before it needs rewiring.

Somewhere in the UK there is a Electrical Trainee miss reading this and going off to stick some T+E under a concrete slab.

 

[Engineer54]

If you install a point to point conduit system you shouldn't need conduit boxes.... It's a bog standard conduit installation system seen in most good multi storey apartment blocks etc.

My house in Cyprus is also wired via an embedded PVC conduit system, as it's a concrete frame block + brick infill. Seeing as the whole installation was wired AFTER the conduit system was installed, and the floors/walls/ceilings had there finish coats, then obviously it will be rewireable too, at some later date!!

 

[grumpyjohn01]

Thanks E54, am aware of that sort of system in europe etc..would you use Kopex (or similar) and PVC singles?..have tried wiring flexi with T&E before......!

 

[Guitarist]

Somewhere in the UK there is a Electrical Trainee miss reading this and going off to stick some T+E under a concrete slab.

See this all the time...Seems a favourite DIY method.

 

[ayjay]

why can,t u run twe behind the base units

 

[7029 dave]

As Eng54 said go box to box with nice slow bends you wont need conduit boxes,Ive pulled through old slip tube in the past on lighting circuits when men were men!!! lol

 

[Engineer54]

Thanks E54, am aware of that sort of system in europe etc..would you use Kopex (or similar) and PVC singles?..have tried wiring flexi with T&E before......!

Point to point embedded conduit systems are as old as surface conduit systems, where conduit boxes are used. Probably a system used more in the UK than in Europe too!!

No i would not use Kopex or similar, standard wall or rigid PVC conduit with slow bends made with conduit bending springs is all you need. Just make sure that all conduit joints and connections are securely glued/bonded, as there are no second chances, once the concrete floor has been poured!! ...lol!!