Andy Hall wrote:

This raises two questions:

1) In effect, this creates a spur - i.e. the daisy chain of the lighting
circuit comes to the ceiling rose position and the cable to feed the
lighting circuit to the edge of the room above the cupboard would be
teed from it. I suppose that I could run two cables and effectively
maintain the daisy chain. I can't find any rules on this in BS7671 one
way or the other.

Since the lighting circuit is a radial there is no actual requirement
for it to follow a linear progression from one light to the next. You
can split it any which way you find convenient - taking "spurs" or
adding branches when you need.

2) I need a solution for jointing the cables at the ceiling rose
position. Crimps are the obvious choice since the hole will be
repaired and covered. However, I could do with a solution to provide
the second required level of insulation etc. Conventional junction
boxes don't seem very suitable because of the screw terminals, although
I suppose those could be removed; but also I don't really want to make
the ceiling hole larger if I can help it. Is heat shrink tube
permissible in this application to provide the second layer of
insulation? Any other ideas?

IIUC heat shrink is acceptable in this case (it would be acceptable for
jointing a cable that you then buried in plaster, so entombing it in the
ceiling void should not be a problem).

Ventilation:

3) I want to move the fan from its current ceiling mount position to
being fitted above the cupboard. There would then be a removable
grille above the cupboard. The idea is to make the ceiling clear, and I
should be able to reduce the noise of the already quiet Vent Axia fan
even further. I can't find any Building Regulations objection to so
doing. Anybody know different?

Can't think of any reason why not.

4) I believe the Buiding Regulations specify that the fan comes on when
the light is switched on and should run for a period of time after it
has been switched off. However, I am intending to have two sets of
lights; one being under-cupboard and the other some downlighters on the
long wall or wall lights. So the question arises of whether the fan
should come on when the "main" light is switched on or when either is
switched on. Obviously I could do the latter with relays.

Comments?

I would go with the "main" light only. The also gives you an easy option
for circumventing the starting of the fan on any occasion that you wish
to so do. (which building reg were you thinking about BTW?)

--
Cheers,

John.

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