On Wed, 20 Aug 2008 02:55:39 +0100, John Rumm
wrote:

Two smaller conduits solve that problem, and are often easier to thread
anyway.

Thanks for the link to the table. Where do you get the figure for
running two or more cables in the same conduit? I was going to run two
separate conduits anyway; partly because I hadn't seen wide conduit in
the shops and partly because like you, I think it would be easier to
push two wires down two separate conduits anyway. Do the regs. say
that the two conduits must be a certain distance apart? Do I have to
chase two separate channels or can I place them together in one wide
channel (the latter would be less work!)

One final question: our house does not have a hall, so you have to
walk from the stairs through the lounge through the dining room to the
kitchen. There are is one light switch at the stair end of the lounge
and one at the kitchen end of the dining room but nothing in between.
I would like to fit two-way switches between the lounge and dining
room. These would be either side of the same (breeze block) wall. I am
concerned if I chased a channel on either side of the wall, I would
effectively be removing twice the depth and would this weaken the
wall? Even if I offset the two channels, I wonder whether the effect
might be the same because they were so close? Is it that you are
allowed to remove one third the depth safely?

I wondered whether I should chase one channel on one side of the wall
to carry both wires and then drill a hole through the wall to take the
second wire to the other switch. Is this acceptable?

Thanks,
Sam.