Surface conduit

[Davidabcd]

dohh!

Thanks for replying!

Basically 32mm conduit would look too bulky - so maybe I'll see if I can do the calculation to justify a 6mm2 supply cable instead.

I just assumed the electrician would pass the cable through the flexible conduit first, then push it onto the wall clips. I didn't visualise doing it the other way round.
David

 

[ban-all-sheds]

Please let the electrician do what he's being employed to do - designing, installing, testing etc.

There's no point you deciding on a cable size, and a method of installing it, if he disagrees.

And BTW - flexible conduit clipped to the wall is going to look disgusting.

 

[ColJack]

if it's in conduit then it doesn't need to be T+E, singles will suffice providing it's in conduit from switch to shower..

 

[sparkwright]

Why has it got to be conduit?

Is it an option to use pipe trunking over all or most of the pipework and run the cable in that (making sure it doesn't touch the pipes)?

 

[Davidabcd]

Thanks for the reply shed - I want to be prepared before employing the electrician. Thanks for the suggestion sparkwright. And others have also said pipe trunking is a reasonable way to go. It's just my personal decision to use flexible conduit (because it fits into my general approach)

From Coljack's suggestion, I have had another (hopefully better!) go at a conduit cable capacity estimation -

overall diam of single 10mm2 cable = 6.1mm
cross sectional area of single 10mm2 cable = 3.05 x 3.05 x pi = 29.2mm2
total cross section of three cables = 3 x 29.2mm = 87.6 mm2

electroflex 20mm conduit has internal diam = 16mm;
radius =8mm
internal cross sectional area of electroflex = 8mm x 8mm x pi = 201mm2

Overall internal space taken up by cables = (87.6 / 201) x 100% = 44%

I'm confident that heat wont be a problem as I believe the 7.5 kW shower can run off 6mm2 cable (surface mounted trunking / conduit)
and I'm confident that the cables can be passed through before the 3m conduit is curved and pushed onto the clips.

Triton state that their 7.5 kW shower can be connected using 20mm conduit - but they wouldn't give technical advice to a diy-er and said that the electrician "would know how to do it".

David

 

[holmslaw]

..

 

[Davidabcd]

Thanks for your suggestion holmslaw!
It's incredible how much I've learnt from this forum in such a small space of time by following up everyone's comments, and cross-referencing them to other DIYnot threads and sites like TLC-Direct and BS7671 guides.

David