Re: CBus introductory course

["David Buckley" <db@xxxxxxx>]

--- In ukha_d@xxxxxxx, "Paul Robinson" <ukcueman@y...>
wrote:
> Hi Rob,
>
> Apart from the qusetion of whether it would work, it was also
suggested to
> me that the regulations require physical separation between cables
that
> carry power from those that don't, even if they only carry DC.

The general requirement for low voltage wiring in conjuction with
mains wiring is that cables in the same enclosure (ie box, conduit,
whatever) must be insulated sufficiently for the highest voltage to
which they are likely to be exposed.

Thus if you have Cat5 cable with mains voltage rated insulation you
may install it in the same cableway as mains conductors.  This is
presumably why Clipsal make the pink Cat5 - I assume (but dont know)
that it is rated for use alongside mains conductors.  Certainly the
EIB Green cable is tested to 4KV in wet conditions, and thus complies.

SELV wiring brings on additional requirements.  (This is just a
discussion on wiring; the other features of SELV are ignored as I
guess if Clipsal say that CBus is SELV, a very specific term, then
they mean it does comply.)

Reading the regs, since the pink cable is double insulated (ie there
is another sheath around the condutors, which are themselves
sheathed) it complies with 411-02-06 pt 2.  Also the signal
conductors may in their own right meet 411-02-06 pt 1. Thus running
CBus cable in the same cableway as mains rated cable should allow the
SELV requirements to be met.  Only compliance with one part is
required.

Therefore use of a CBus light switch in a bathroom should be passed
by an inspector, assuming _all_ of the SELV regs are met.