On 12/12/2012 16:39, David B wrote:
"Don Pearce" wrote in message
...
On Wed, 12 Dec 2012 16:14:00 -0000, "David B"
wrote:

Hello,
Sorry for posting an off topic question but I know you all know your
electrics.

I'm trying to change some light switches for PIW switches so they
come on
when my disabled brother walks into the room.
My problem is that the PIW switches require a live in, a live out and a
neutral and light switches in the UK only have a live in and a neutral.

Can I connect the live out to the neutral as well as the neutral to the
neutral as shown inn my diagram he

http://www.flickr.com/photos/4905729...in/photostream

The crossed out line is what don't have and want to replace with the
dashed
line.
Being as the switch controller is drawing such a low current will
this make
any difference to the outcome? Will they now be in series rather than
parallel and would this matter?

Thank you

David

Uk light switches have a permanent live in and a switched live out -
no neutral. You will need to run new cabling to the switch for this
job.

d

Sorry, my terminology was wrong. Yes I really need one more cable as
shown crossed out in the diagram but why wouldn't it work anyway?
(Excuse my ignorance)
As far as I can see, in the off position it would be the same as having
a 0.25A fuse in line with the controller (which should make no odds) and
in the on position the switch and bulb would be in series.
Would this not work?


In the on position there would be no voltage for the "switch controller"
in your diagram so it would turn itself off.

You could mount the sensors on the ceiling near the light,
where you can access a switched live and a neutral.
Or you could try to feed another wire up the duct from the light switch
to the light to pick up a neutral. For the ground floor you would probably
have to lift the floorboards upstairs. For the bedrooms, loft access
will do.

--
Eiron.