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ian hall

Can someone confirm the correct reference methods for

Twin and earth drilled through joists and enclosed in pvc capping buried in plaster.

As above, but cable run on top of fibreglass then in capping down to a switch

Twin and earth run in surface mini trunking

Thanks

Ian Hall
 
bare in mind i'm semi-p*ssed ,in joists isn't it usually classed as free air?have a look at table 4c1 page 268 (bunched in air)
when i've got a mix of installation methods i look at where its run for the greater length and the most onerous condition
someone else can figure out the rest!!!!!!!!!!!!
 
i would find the worst case scenario of the grouping methods you are using for that particular circuit then use that as your reference method, cant go wrong.....
 
Can someone confirm the correct reference methods for

Twin and earth drilled through joists and enclosed in pvc capping buried in plaster.

As above, but cable run on top of fibreglass then in capping down to a switch

Twin and earth run in surface mini trunking

Thanks

Ian Hall

well the new reference methods are wierd

aint got the regs in front of me, so its off memory, but.....

tw&e buried in plaster, (in capping is irrelevent) is method B

in surface mini trunking is C (which drops 2.5 for example from 27A at B, to about 23 amps with C)

cables run on top of fibreglass is between methods 100-105 (again, i aint got the regs)

but run through joists is the odd one....if you read the descriptions, clipped direct to a wall, is B, but in an enclosed space (or void) above a ceiling is C, look at the diagram, so the way i read it, the current carrying capacity in the free space between floors is LESS than if its buried in plaster in a wall?

erm.... maybe i'll have a another look tommorrow...but it dont sit right...and i've read it and read it:cool:
 
That is exactly what i have come up with. Seems odd mixing letters and numbers! there again the box in the Niceic forms is a little bigger than just for a letter!!!! if you see what i mean.


Ian
 
i have seen 2 certs today both have diffrent refrence methods numbers then letter .. cooker 40a ref method 1 ref method A / rn / r2 /r1 / L-N/ L-E

but nothing on form to show what refrence methods are ..
 
I was gonna reply to this and mention that C is the buried in plaster, and B would be in containment.

Then I realised that the thread was 18 months old, why drag up such an old thread Mr Fuse?! ;)
 
i did a search for ref methods just to see if thay are diffrent ones ?? like 1 2 3 4 5 6 /A B C D E F i did not look to see what date it was .. just a bit confused on the 2 certs i seen with both ref methods as numbers and letter ..
 
16th edition was numbers

1 - clipped direct (maybe in plaster)
3 - in containment
11 - on tray or ladderwork

17th editon

C - clipped direct
B - in containment
E or F - on tray

All these are vast generalisations, and there are different ones for twin and earth which should be looked at.

What you may be seeing is the NICEIC cable types that they have at the bottom of their sheets, these are: -

A - PVC/PVC - i.e. twin and earth
B - PVC in metallic conduit
C - PVC in non-metallic conduit
D - PVC in metallic trunking
E - PVC in non-metallic trunking
F - PVC/SWA - thermoplastic steel wire armoured
G - XLPE/SWA - thermosetting steel wire armoured
H - MICC
O - other - is whatever you put in the box - i.e. FP200, SY etc...

I hope this helps! :)
 
on the form thay was 2 collums ... ref method .. A/6 for cooker shower A/6 floor ring A/3 top ring A/3 lighting A/6
lighting A/6 outdoor lighing B/1 shed A/6

never seen 2 form like this ... i normaly see A/B/C
 

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