Andy Dingley wrote:
On Dec 7, 11:56 pm, Lobster wrote:

And/or does that present potential
overheating problems?

The numbers change (in your OSG), but it's no big deal. Bundled cables
are bundled cables, and there's less de-rating due to heat from
surface conduit than under loft insulation.

Have a look here

http://wiki.diyfaq.org.uk/index.php?...lation_Methods

Although the figures are correct the page is halfway through an update to
fetch it into line with the 17th edition reference methods (I'll see if I
can update it a little more tonight)

A 32A ring and 6A lighting are unlikely to cause problems when used in
conduit together. It may well be possible to ignore the lighting circuit for
grouping factors if it is only at 33% of it's capacity.

Remember to tell
your teenage assistant this, or at least "Don't force it if it won't
go, stop and ask". It's a right pain to be "finished", then find that
half your backboxes are now broken and you have to strip the whole lot
out! Don't use teenagers as labourers if they're likely to take the
"sweep it under the carpet" approach to problems, especially not if
they then repeat it on a whole row before you find out.

Do you speak from experience here? I sense a bit of ill feeling. Do tell us.

--
Adam