Running cables in floor ducting in screed floor

[sb1456]

I'm about to get my extension floor screeded (50mm), and i'm going to put 50mm galvanised floor ducting in to run the central heating pipes to the radiator, can I share this ducting and use it to partly run the electrics.

If not, what is the preferred method to run electrics through a screed floor.

The finished floor will be tiled over.

many thanks

 

[tonyelectric]

No the electrical cables should be kept separate unless your ducting has some form of partitioning specially designed for the application. I would be tempted to run the cables in a 20mm or 25mm round conduit, this can be steel or plastic (plastic being easier for the DIYer as no special tools are needed except a bending spring that costs only a few quid, then if you ever need to replace the cable/wire you can do so without tearing up your floor, you will need to ensure whatever conduit you select is big enough to take all the cables you need allowing them to be drawn round any bends. Its also a good idea to include a peice of 1.5 or similar earth wire (or any kind really) with the pulled through cables/wires in case you need to pull something extra through later.

 

[ban-all-sheds]

... extension ...

If you're in England or Wales, what did you say would be the way you'd comply with Part P? That's a genuine, and important question, because how you go about resolving your questions etc depends on what LABC are expecting you to do, and it won't be much fun if you take the wrong path now and then can't get a completion certificate at the end.

floor screeded (50mm), and i'm going to put 50mm galvanised floor ducting in to run the central heating pipes to the radiator, can I share this ducting and use it to partly run the electrics.

Best not to, or you'll have to de-rate the cables for high ambient temperatures.

If not, what is the preferred method to run electrics through a screed floor.

Either:

1) In their own conduit/ducting

or

2) The method that your electrician wants.

 

[PrinceofDarkness]

Yes, you can run cables in a shared u/f duct with heating pipes - provided that those pipes are lagged and that the cables are suitably rated for the likely temperature within that 'enclosure'. And there's no need for 'partioning of the duct, either!

Ignore that "genuine and important' question from 'BAS' regarding Part P, he means well - but he doesn't really step outside of his DIY realm very much.

So, just get on with it.


Lucia.

 

[bernardgreen]

When you intall the ducts solvent weld the joints before concrete is laid.

Very annoying to find the concrete pouring separated a joint.

 

[PrinceofDarkness]

I don't actually see the need to fit galvanised trunking in a shallow screed - simply for the sake of heating pipes to a radiator. The pipes can be 'HepSleeved' and buried directly into the screed - and so can the cables be buried in the screed, preferrably enclosed in conduit - but not essentially so - provided that it's an RCD protected circuit.

Lucia.

 

[Chri5]

Depends of the flooring system that goes down.

If you want to future proof the fixed floor so that a rewire can be done in 30 years then planned accessible containment is the only way.

My tiler mate just put down some tessellated Victorian tiles that costed in at £200 a metre, so god only know the final cost was.

No matter where the cable route is, in floor, in wall the decision to make a route that can be replaced is one for the site spark and the client to agree on.

You could go with a spine in earthed box galv and tee off that in plastic to socket and switches. Same size conduit even on the arterial runs is near impossible if you have more than one circuit ring.

 

[holmslaw]

..

 

[sb1456]

Thanks for all the replies peoples, probably go with laying the electrics in seperate conduit directly into the bottom of the screed.