I have light on the hallway and another on the upstairs landing.
They are controlled by two identical double switches, one upstais
one downstairs. The upstairs switch seems fine, however the
downstairs hallway double light switch looks like this..

http://www.duab.co.uk/switch/

That's how it has been wired for 10 years until the lower red
wire came loose recently and the upstairs landing light stopped
working. I refitted it and now the light works again, however,
the back-box and fixing screws now show as "live" with my
test-screwdriver. I noticed this as I was refitting the screws
and the driver showed as live.

As can be seen here www.duab.co.uk/switch/DSC01167.jpg the two
earth wires are not fixed to the back-box.

Can anyone tell if this is wired correctly from the photo's?

Thanks,
Mike.

On Fri, 10 Dec 2004 18:39:46 +0000, Mike strung
together this:

Can anyone tell if this is wired correctly from the photo's?

It looks untidy and I wouldn't be happy if it were one of mine. There
should be red sleeving on the blues and yellows and the earths should
be connected to the back box.
--

SJW
Please reply to group or use 'usenet' in email subject

"Mike" wrote in message
...
I refitted it and now the light works again, however,
the back-box and fixing screws now show as "live" with my
test-screwdriver. I noticed this as I was refitting the screws
and the driver showed as live.

The muppets who wired my place failed to connect the earth for the entire
upstairs circuit back to the earth bar on the CU with the result that the
back-boxes and fixing screws would give you a light shock if touched. The
capacitive coupling of the live wire on the earth conductor induced an AC
voltage of 240v
on all the interconnected backboxes etc. Shocking, but not very dangerous,
as the jolts were never high current.

The reason I mention this, is that is *possible* that the "live" measurement
you get with the test screwdriver is due to the same effect. However, unless
you **know** that the voltage on the metalwork is not due to it being
connected to directly to the live conductor it could be dangerous to just
assume it is. (i.e and connect the earth). You really need to test the
phase-metalwork impedance to ensure it is not a short.

As for the wiring, without seeing the way the pendants are wired, I wouldn't
like to comment. But from what I can make out in the photos, I couldn't see
a clear error. But I wouldn't be very confident as I am not sure which wires
go where.

YMMV
E&OE

On Fri, 10 Dec 2004 18:39:46 +0000, Mike strung
together this:

the back-box and fixing screws now show as "live" with my
test-screwdriver. I noticed this as I was refitting the screws
and the driver showed as live.

The other thing, neon screwdrivers aren't really any use for accurate
testing, they show live when they feel like it and don't when they
don't, not to be relied upon as an accurate indication, more of a
rough guide as to the liveness of a particular thing.
--

SJW
Please reply to group or use 'usenet' in email subject

In article ,
Mike wrote:
Can anyone tell if this is wired correctly from the photo's?

The normal way to wire a two-way switch circuit using triple and earth
where the switch pair is at one switch is to wire Com to Com, L1 to L1 and
L2 to L2 using the triple and earth, and then the switch pair across
L1 & L2.

Thus:-


L1 L1
0===========0 0===========0============= Line
| \ / |
C 0================================O C
\ / \ /
0===========0 0===========0============= Switch return
L2 Optional L2
Intermediate

--
*Why do the two "sanction"s (noun and verb) mean opposites?*

Dave Plowman London SW
To e-mail, change noise into sound.