T&E in conduit in screed?

[SUNRAY]

I can't help thinking that singles could prove to be a PITA.

As I understand it, nine or ten conduits wouldn't be a problem.

I love to work with singles, and yet they would make a fairly easy transition of the floor, but in this situation all I can foresee is a ruddy great JB.

 

[Echo the husky]

Sheathed MICC and just bury it in the screed.

 

[JohnW2]

Sheathed MICC and just bury it in the screed.

No-one seems to have suggested burying T+E in the screed, yet!

Kind Regards, John

 

[Echo the husky]

No-one seems to have suggested burying T+E in the screed, yet!

Wrap the T+E in Denso tape first!

 

[SimonH2]

... all I can foresee is a ruddy great JB.

That's what I was thinking - unless the whole job is done in conduit (the 1960s called) there will need to be a transition between T&E and singles.

 

[rsgaz]

there will need to be a transition between T&E and singles.

Yeah, in the box at the huge bank of switches he will need!

 

[SimonH2]

No, the signles can go right into that box (if the conduit is run into it) - but at the other end at some point they'll need to convert to T&E meaning a big JB somewhere else. The alternative being to run the whole setup in conduit like they did in the 60s and keep to the singles all the way.
I suppose he could use one of the those big JB lighting wiring centre boxes for the transition - singles to the switches, T&E to the lights.

 

[EFLImpudence]

What is wrong or undesirable about a 'big' junction box?

Does anyone have central heating?

 

[ToastyToes]

Considering only a 1.5m length will be under the screed, and assuming the installation comprises of T&E, isn't the op better off using 20 or 25mm plastic flexible conduit - as he orginally suggested?

Would be advisable to only run one or two cables in each though.

I am assuming that this is for a kitchen island, so the containment needs to turn up at either end. Floor trunking riser bends are horrid, I've never seen a swept bend, only an awful 90° bend or a 'slightly better' double 45° bend, such as...



Unless the OP has walls about 8 inches thick, then that can't be chased into the wall and still meet the one third depth rule. Pulling cables through after is has been set under the screed and plastered over in the wall causes the sheath to be damaged on the bends, especially when some screed/plaster has leaked through and made it nice and rough! Abrasive in fact! Unless you are going to make it totally water tight first.

Also, I'm assuming he will be having a large grid system wall box for all the switches...


Floor trunking won't mate very well with it, whereas conduit clearly will. You can see with that particular box I have shown, it has three 20mm knockouts along the bottom. They could easily be enlarged to 25mm and add two extra 25mm holes between them, so 5 25mm conduits, all ran in singles would be ideal. Nice swept bends, easily presentable at either end.

I wondered if it was too expensive, too overkill, and too specialised for a simple 1.5m run in a house - but I'm open to opinions.

I love to work with singles, and yet they would make a fairly easy transition of the floor, but in this situation all I can foresee is a ruddy great JB.

No-one seems to have suggested burying T+E in the screed, yet!

Kind Regards, John

That's what I was thinking - unless the whole job is done in conduit (the 1960s called) there will need to be a transition between T&E and singles.

Thanks all for your suggestions.

Attached is a diagram of what I am looking to do. Blue box = timber suspended floor, Red box = kitchen extension with the concrete floor.

Here are a couple photos of the kitchen before the timber floor was installed.

 

[ban-all-sheds]

I am assuming that this is for a kitchen island

Apparently not, but if it had been then an alternative to a riser bend under it would have been a floor box....

 

[SUNRAY]

Would this work instead?:

Drill diagonally through the wall from under the units to under the floor in the area not bounded by blue or red rather than in the red area floor.

Sorry it's very far out of scale so probably looks a lot worse than it really is.
or possibly stop short of the support

 

[SUNRAY]

Or possibly stop short of the supporting wall

 

[ToastyToes]

Would this work instead?:

View attachment 149574
Drill diagonally through the wall from under the units to under the floor in the area not bounded by blue or red rather than in the red area floor.
View attachment 149575Sorry it's very far out of scale so probably looks a lot worse than it really is.
or possibly stop short of the support

Or possibly stop short of the supporting wall
View attachment 149576

Hi Sunray. Thank you for your diagrams.
I did think of doing it as you suggested (through the side wall) but I was concerned about drilling multiple holes and weakening the wall which is not very wide and has a large RSJ sitting on it which holds the back of the house up. I could drill one hole and fit them all in but to reduce any grouping/heat issues as mentioned previously, I'd want to split up the cables.