RE: Lights, cabling, CBus, etc.

["James Hoye" <james.hoye@xxxxxxx>]

> >And leading on from that, what cabling should I use for the
lights.
> >Is 2.5mm T&E suitable?
>
> I'd be surprised if you *need* to use 2.5mm for lighting
> circuits. I believe
> it is more normal to use 1.5mm for lighting, and 2.5mm for
> sockets...  In a
> similar installation I recently did, I ran 1.5mm T&E to the joist
> immediately above each fitting, then fitted a 20A junction box, and
ran a
> short length of 13A flex to each light fitting, - mainly because the
> terminals on the light fittings seem to work better with stranded
> cable, and
> its quite a bit easier to work with the fittings during installation.

What is important is that whatever cable you choose, it is suitably
protected by a fuse or MCB.

Obviously if you are running several kW of lighting, then you would need
something beefier than 1mm.  Also there are other factors to consider -
like
what sort of materials the cable passes through [fibre glass insulation
will
actually derate a cable] the fixing method employed [whether 'clipped
direct', buried, free air etc.], how many cables are bundled together and
the length of the run - really long runs will drop voltage.

Domestic wiring is usually over-rated and in most circumstances will do
what
you need, but if you are loading cables to their limit then you must be
aware of and allow for these sort of things.

http://www.amazon.co.uk/exec/obidos/ASIN/0953788504/markmccall
is a good
book for this sort of stuff.

Usual disclaimer applies - make sure YOU are aware of what is
required/allowed in YOUR circumstances.

James H