|Thanks for the suggestions.
|The floor above is concrete, so it's not dependent on the ceiling joists
|for support. I reckon it might be possible that there would be space
|between it and the ceiling to thread wires (I hope!).
|If I did need to make a few extra holes in the ceiling to negotiate the
|joists, is there a simple way to fill them without having to replaster the
This is what I did...
Near the existing light cable, I made a hole big enough to get my
hand through (approx 4 inches, mine was square and I only cut 3
sides to make a sort of hinge). Inside the ceiling now, I fixed
the transformer to the nearest joist using the hole for access,
and wired it into the existing feed. Then, inside the hole, I
measured the space to the joist I wanted to hop under first.
Repeat this measurement on the underside of the ceiling and, from
below, cut (stanley knife) the plasterboard across the joist.
Pull the wire through, under the joist, tape it the end of a
coathanger, and push it along to the next joist.
Now you know the distance between joists you can cut small feed
trenches exactly where you want, and feed the low-voltage cable
around/across the ceiling. As you progress, the holes you make
for each downlighter help with the feeding process too. I ended
up with a series of holes which were each the size of a small
nail-file, - easy to fill with polyfilla. You can fill the hinged
acess hole by pulling it down slightly higher than flush, gluing,
and then 2 thin layers of polyfilla or plaster top-coat, sanding
in-between, before painting.
Might be a bit of a heath-robinson solution, but it took me less
than a day for 12 downlighters and nobody can see anythng but a
smooth ceiling. The low voltage can easily have a 2" bit of
filler over it without risking fire or damage.
Hope it helps a bit.
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