Advice on laying cables in screed/concrete?

[Tarzan]

A customer of mine has had a single storey extension built on the side of his house. I am planning to extend the existing ring main in to the extension as there is a existing socket backing onto the new extension. There will be approx eight new double sockets. I have two options regarding cable routes the first being, clipping the t-e up the block,capping over the top,boarded and plastered. 2nd option, 20mm plastic conduit from every back box, down the wall, accross the floor,up to the next back box and the conduit screeded over the top. screed will be approx 5 inches thick. Customer wants me to go with 2nd route for ease of installation and they want to leave joists exposed. Consumer unit has rcd protection. Looked through regs and cant clarify if this is a viable option. Any advice would be great! tim

 

[green-hornet]

I did a similar job where I thought of the future requirements of the instalation, what I did was I used 2 inch waste pipe with resin joints buried in the concrete, but this provided me with cable routes from one side of the kitchen to the other.

The other option was to do 2 radial circuits for the kitchen.

I thought my option had more versatility.

 

[Pyro]

Definitely conduit in the screed! I've done this on several jobs.

IIRC it's covered in Steward & Watkins "Modern Wiring Practice".

Both steel and PCV (high impact) conduit work well in this application.

Easiest to run singles in 20mm conduit; if you go to 25mm you can run T&E a lot easier (there are 2 x 90 degree bends to get round) and plan to have only 1 x T&E or 3 x singles per conduit. A 5 inch screed is good news for sweeping bends to make cable pulling easier.

Is there a need for other electrical services - phone, TV, datacomms, etc. that need installing in the extension?

Pyro.

 

[Pyro]

What the heck's this auto-selection of the symbol PI when the letters P and I are next to each other as in sweeping s w e e p i n g, pipe p i p e, capping c a p p i n g?

 

[a1]

Sorry Pyro, I have corrected that - as you can now see from your post above.

Welcome back - I haven't seen you on here for a while.

 

[Pyro]

Thanks Admin (for the welcome back and sorting out the PI. Hmmm PIE, lunch is needed!).

I have not really been away, mainly lurking and reading.

Cheers,

Pyro.

 

[sparky999]

Yh i have done a similar job where it was a glass reception area where no cable routes could be put in so wired the sockets in some 25mm conduit and singles, with each socket outlet being in flexi conduit to the ground into the through boxs, i thought it was a very good neat way of doing it.

 

[Tarzan]

thanks for replys chaps. wired today using galv conduit and singles.