reference methods

[pickleye]

Just filling out circuit details on NICEIC sheets for my NVQ.

The job we've done is a school rewire. LSOH Cables come from DB onto basket routed through uninsulated ceiling void, then clipped direct to timber roof trusses (no insulation, suspended ceiling), then finally a drop to swiches/sockets etc in PVC conduit.

What reference method would you suggest fits this situation?

E Perforated Cable Tray/ Ladder/ Free Air (Multi core)

C Clipped or fixed direct ( not enclosed)

B Multicore cable in conduit in masonry wall

I don't want the "answers to homework" more of a guidance how to look at this problem. Would you suggest looking at the worst thermal effect and using that, noting that method, or the longest section of each method. :C :C:C:C:C

Suggestions welcomed.

Thanks.

 

[PC Electrics]

I would say that when you have a cable which has several methods along it's run then the one you use for design calcs (and the cert) is the one with the lowest ccc. Which in this case will be B.

As buried direct in masonary is the same ccc as clipped direct why put the cable in conduit? It lowers the ccc and could in some circumstances force the use of a larger csa.

 

[Doc Hudson]

On some occasions I have seen two methods written in the box, but this can get cumbersome with 3 or more methods. I think the longest run of the most prolific method is probably appropriate. But if you want more detail, because it may be beneficial to anyone looking at your certificate at a later date, you could always add an extra sheet with any relevant comments and make reference to it in the box on the EIC.

Doc H.

 

[steptoe]

I agree with PC does my NICEIC assessor,

use the worst scenario, ie, the one that downgrades the cable the most.

 

[NozSpark]

+1

You should always use the worst case scenario.

 

[pickleye]

Thanks for the help guys, Noz, steps it makes sense to use the worst case scenario.

PC, we haven't done the calcs as the job was designed and speced by A.N Other. That includes putting the drops in PVC conduit - not sure why, other than easier to pull out in the event of a modification being required - its not going to be nail proof that's for sure.

Doc, good point about additional points on separate sheet.

 

[ianmacd]

I assume you are using a multi sign cert then?

 

[pickleye]

Sure are, actually a blank photo copy as only for NVQ, but yes separate signatures.