Looking at a nearly completed extension the other day, I noticed that
there were two separate cables awaiting connection in each light switch
patress, one being a live feed and the other going to the light
fitting.
I know how lighting is wired in the style where one cable carries a
live feed through the switch back to the junction box then to the lamp,
but how is this style wired up?
Thinking about it, there seems to be one connection point short using a
conventional light switch.

wrote:

Looking at a nearly completed extension the other day, I noticed that
there were two separate cables awaiting connection in each light switch
patress, one being a live feed and the other going to the light
fitting.
I know how lighting is wired in the style where one cable carries a
live feed through the switch back to the junction box then to the lamp,
but how is this style wired up?
Thinking about it, there seems to be one connection point short using a
conventional light switch.


There is.

Common the neutrals using a connector block, and maybe the earths as
well, but take a 'tail' from that to earth to the switch metal, and use
L1 and common for the two reds (or whatever colour they are these days)

The Natural Philosopher wrote:
wrote:

Looking at a nearly completed extension the other day, I noticed
that
there were two separate cables awaiting connection in each light
switch
patress, one being a live feed and the other going to the light
fitting.
I know how lighting is wired in the style where one cable carries a
live feed through the switch back to the junction box then to the
lamp,
but how is this style wired up?
Thinking about it, there seems to be one connection point short
using a
conventional light switch.


There is.

Common the neutrals using a connector block, and maybe the earths as
well, but take a 'tail' from that to earth to the switch metal, and
use
L1 and common for the two reds (or whatever colour they are these
days)

Thanks. So one has to put a connector block in the back box?
How is this better than using junction boxes in the ceiling void, or am
I missing something?

Thanks. So one has to put a connector block in the back box?
How is this better than using junction boxes in the ceiling void, or am
I missing something?

Because the joint is accesible much more easily than under floorboards.

Dave

wrote:
The Natural Philosopher wrote:

wrote: There is.

Common the neutrals using a connector block, and maybe the earths
as well, but take a 'tail' from that to earth to the switch metal,
and use L1 and common for the two reds (or whatever colour they are
these days)

Thanks. So one has to put a connector block in the back box? How is
this better than using junction boxes in the ceiling void, or am I
missing something?

I think just when specific circumstances dictate; eg I'm shortly going
to be fitting an outside light; the switch will be almost directly on
the other side of the wall from the light's location, and it will be
under the stairs which will make it a sod to get cables to. Using
junction boxes above the ceiling I'd need to run two cables (would be
about 4-5m long); one running to the switch, the other to the light
fitting. Far easier to have a single cable running down to the switch,
and then another short one through the wall to the light fitting,
handling the switching wiring using a connector block behind the light
switch.

David

OK, I see. Thanks, all.

wrote:

The Natural Philosopher wrote:

wrote:


Looking at a nearly completed extension the other day, I noticed

that

there were two separate cables awaiting connection in each light

switch

patress, one being a live feed and the other going to the light
fitting.
I know how lighting is wired in the style where one cable carries a
live feed through the switch back to the junction box then to the

lamp,

but how is this style wired up?
Thinking about it, there seems to be one connection point short

using a

conventional light switch.


There is.

Common the neutrals using a connector block, and maybe the earths as
well, but take a 'tail' from that to earth to the switch metal, and

use

L1 and common for the two reds (or whatever colour they are these

days)

Thanks. So one has to put a connector block in the back box?
How is this better than using junction boxes in the ceiling void, or am
I missing something?

Easier to get at when they fall to pieces?