Simple mains question..
 

I'm running both sides of a 2.5 T&E ring through the same 16x32mm
conduit
including running one 2.5 T&E unadulterated neatly through the back of
the
30mm pattress whilst the other one is cut, stripped, trimmed, and
twisted.

I've read through my books and I cannot see anything saying that I
cannot do that, but you guys seem to have an encyclopaedia's knowledge
of
the regs so I thought whilst I'm still early on I'll ask for
comments.
Better to fix things now then to be shot down by the BCO or P
Competant..

Any comments?
JJ

- this was on the bottom of a longer rambling post I have now deleted,
in the hope of tempting some replies :)

Simple mains question..
 

On Tue, 26 Jan 2010 06:02:21 -0800, JJ wibbled:

I'm running both sides of a 2.5 T&E ring through the same 16x32mm
conduit
including running one 2.5 T&E unadulterated neatly through the back of
the
30mm pattress whilst the other one is cut, stripped, trimmed, and
twisted.

I don't see any issues. Technically, with round conduit you would apply a
grouping factor for 2 circuits in one tube - but as 16x32 is likely to
leave the cables apart, each one should suffer less as it will
effectively have its own bit of conduit/plaster surface to lose heat
through and it's the heating/cooling that rates the current carrying
capacity of a cable.






--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

Simple mains question..
 

I don't see any issues. Technically, with round conduit you would apply a
grouping factor for 2 circuits in one tube - but as 16x32 is likely to
leave the cables apart, each one should suffer less as it will
effectively have its own bit of conduit/plaster surface to lose heat
through and it's the heating/cooling that rates the current carrying
capacity of a cable.


good point, the gap required for spaced circuits is something like 1
cable thickness?

so two 2.5 T&E in 32mm ducting taped to top and bottom of the duct
pretty much eliminates any grouping effects for the entire run in any
case?

the way I see it I'm unlikely to have any problems in any case, but if
I use some black nasty tape in a couple of places to ensure the two
cables are well separated I can make sure of it. no doubt that will
help with my "peace of mind"...

Simple mains question..
 

JJ
wibbled on Tuesday 26 January 2010 15:30

I don't see any issues. Technically, with round conduit you would apply a
grouping factor for 2 circuits in one tube - but as 16x32 is likely to
leave the cables apart, each one should suffer less as it will
effectively have its own bit of conduit/plaster surface to lose heat
through and it's the heating/cooling that rates the current carrying
capacity of a cable.


good point, the gap required for spaced circuits is something like 1
cable thickness?

so two 2.5 T&E in 32mm ducting taped to top and bottom of the duct
pretty much eliminates any grouping effects for the entire run in any
case?

the way I see it I'm unlikely to have any problems in any case, but if
I use some black nasty tape in a couple of places to ensure the two
cables are well separated I can make sure of it. no doubt that will
help with my "peace of mind"...

I wouldn't worry too much - but you could shove a bit of small oval
(smallest size should fit) down the big oval between the cables if you
wished to guarantee separation.

--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.