Apologies for the amount of questions. I would appreciate some thoughts on these please...
Grouping factors for cable, and installation methods
Grouping...
AFAIK they are no they are no distances specified for when a rating factor has to be applied for grouping.
So if say three circuits went through the same knock out in a consumer unit, so only together for a tiny distance , would that be considered grouping?
Quite ofter you see cable in plastic trunking from the floor to the CU, to tidy the cables up.
Sometime you can have the majority of the cables in the trunking.
It might only be for 200 or 300mm. Grouping required? This is with the conduit not rammed full (45% I believe)
At what sort of length would grouping become a factor?
Is cable going through notches or holes in joists considered to be grouping them?
Note 9 Table 4C1
I don't understand it
a cable expected to carry no more than 30% of its grouped rating?
So say you had two 6A lighting, a 20A radial and a 32A ring final sharing some conduit...?
Installation methods (Twin and earth) all hypothetical..
If you put a single circuit in pvc oval capping (As cable protection) to be plastered into the wall, would that be method be B or C
If you ran a single cable in plastic flexible copex for 2-3 meters of its overall length (say 25m)
to protect the cable for a short section
Being a single circuit, even if you did derate it, its never usually a problem however.
I guess its about length again, when does adding cable protection change the installation method from clipped direct to In conduit.
Thanks
Grouping factors for cable, and installation methods
Grouping...
AFAIK they are no they are no distances specified for when a rating factor has to be applied for grouping.
So if say three circuits went through the same knock out in a consumer unit, so only together for a tiny distance , would that be considered grouping?
Quite ofter you see cable in plastic trunking from the floor to the CU, to tidy the cables up.
Sometime you can have the majority of the cables in the trunking.
It might only be for 200 or 300mm. Grouping required? This is with the conduit not rammed full (45% I believe)
At what sort of length would grouping become a factor?
Is cable going through notches or holes in joists considered to be grouping them?
Note 9 Table 4C1
I don't understand it
a cable expected to carry no more than 30% of its grouped rating?So say you had two 6A lighting, a 20A radial and a 32A ring final sharing some conduit...?
Installation methods (Twin and earth) all hypothetical..
If you put a single circuit in pvc oval capping (As cable protection) to be plastered into the wall, would that be method be B or C
If you ran a single cable in plastic flexible copex for 2-3 meters of its overall length (say 25m)
to protect the cable for a short section
Being a single circuit, even if you did derate it, its never usually a problem however.
I guess its about length again, when does adding cable protection change the installation method from clipped direct to In conduit.
Thanks
