twin and earth cabling size for commercial buildings

[default]

103 is with thermal insulation which greatly de-rates the cable.

Depending on length of run. Anyway this is all hearsay. That's why you would need more info. If someone said to design an installation & the installation method was " Behind the wall in the cavity " you'd want a bit more to go on. "Throw me a fricking bone". Clipped direct it is not.

 

[cireland]

It is still the closest to the actual installation. There is no insulation which rules out the 100's.
There is no tray, conduit or trunking. It sure as hell ain't method G.
The only difference between this and 'C' is there are no clips.

 

[default]

It is still the closest to the actual installation. There is no insulation which rules out the 100's.
There is no tray, conduit or trunking. It sure as hell ain't method G.
The only difference between this and 'C' is there are no clips.

And the fact it says clipped direct. I though that ment on the surface & visible, which it wouldn't be. Form what the OP is suggesting there is no classification. This is a new install with new walls going up. It's been surmised it's somehow behind an internal wall, in a cavity, clipped, with no insulation present. All I'm saying is more classification is required. You can't price for a job with best case scenario. It's worst case or having the correct information.

 

[JBW175]

Well he’s going have to clip it to something, or put it in containment of some sort.

We can’t have cables just hanging round unsupported throughout their runs.

 

[default]

Well he’s going have to clip it to something, or put it in containment of some sort.

We can’t have cables just hanging round unsupported throughout their runs.

Who said you could, that's why you'd go back to the main contractor for more information, and if it went in some sort of containment that would also change the outlook.

 

[JBW175]

Who said you could, that's why you'd go back to the main contractor for more information, and if it went in some sort of containment that would also change the outlook.

He’s the design consultant, he’s asking us for advice.

We’re giving him our opinions on how we interpret the regs and what to do in our experience.

What would you suggest?

 

[loz2754]

Table 4A2 number 40 gives ref method B, single or multiple cable in a building void.

 

[default]

He’s the design consultant, he’s asking us for advice.

We’re giving him our opinions on how we interpret the regs and what to do in our experience.

What would you suggest?

Yes. The advice is to get more information from the main contractor so you can make a more informed decision.

 

[davesparks]

And the fact it says clipped direct. I though that ment on the surface & visible,

Clipped direct means nothing about the visibility of the cable.
It means that the cable has been clipped directly to whatever it is installed on, no containment or anything else has been installed.

You may be confusing method C with clipped direct? Clipped direct is one of the methods which get grouped together as method C, cables embedded directly in plaster or in capping etc are also method C.