Simple enough job, usually.

We have a pair of 2ft florescent tubes under kitchen wall cupboards,
daisy chained and controlled by a switch within one of the cupboards.
The switch is standard wall mounting, with back box. The switch started
to play up, not always supplying power, so yesterday, I replaced it.

The incoming power is standard grey sheathed T&E, and I rather suspect
comes as a spur from a nearby 13 amp socket. Live and return are red
and black. Power from switch to lights is ordinary flex, as you would
use with a table lamp, or similar, with modern colours - blue, brown
etc. The switch itself was a monstrous thing, obviously designed for
far more than a light. Possibly a cooker. Twin pole, plus substantial
earth connections.

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch. Switch itself is plastic, as is the back box. Have
I done anything slightly naughty, inadvisable or dangerous?

--
Graeme

On 23/03/2017 07:50, Graeme wrote:
Simple enough job, usually.

We have a pair of 2ft florescent tubes under kitchen wall cupboards,
daisy chained and controlled by a switch within one of the cupboards.
The switch is standard wall mounting, with back box. The switch started
to play up, not always supplying power, so yesterday, I replaced it.

The incoming power is standard grey sheathed T&E, and I rather suspect
comes as a spur from a nearby 13 amp socket. Live and return are red
and black. Power from switch to lights is ordinary flex, as you would
use with a table lamp, or similar, with modern colours - blue, brown
etc. The switch itself was a monstrous thing, obviously designed for
far more than a light. Possibly a cooker. Twin pole, plus substantial
earth connections.

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch. Switch itself is plastic, as is the back box. Have
I done anything slightly naughty, inadvisable or dangerous?



Doesn't sound good.

The 'spur' is worrying if nothing else. The ring main will be 'fused' at
30A, you've got lighting flex protected by the same 'fuse' (or breaker)
by the sounds of things.



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Graeme wrote:

The incoming power is standard grey sheathed T&E, and I rather suspect
comes as a spur from a nearby 13 amp socket.

What size is the T&E cable? can you trace it to where it comes from?

If it's a spur from a ring circuit, but isn't a *fused* spur, you likely
have a 32 amp MCB (or 30A fuse if older) protecting the thin flex to the
lights ... if it's actually a re-purposed cooker point instead of a spur
from the ring, it could be worse on a 40A or higher MCB.

In message , Brian Reay writes
On 23/03/2017 07:50, Graeme wrote:

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch.

The 'spur' is worrying if nothing else. The ring main will be 'fused'
at 30A, you've got lighting flex protected by the same 'fuse' (or
breaker) by the sounds of things.

Hmm. Yes, I had not thought about that. I was thinking only of my
switch substitution. I'll have to do some experimenting, and see which
fuse controls those lights. I changed the switch live.
--
Graeme

Graeme wrote:

I'll have to do some experimenting, and see which
fuse controls those lights. I changed the switch live.

Yet you still need to ask:

Have done anything slightly naughty, inadvisable or dangerous?

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On 23/03/2017 07:50, Graeme wrote:
Simple enough job, usually.

We have a pair of 2ft florescent tubes under kitchen wall cupboards,
daisy chained and controlled by a switch within one of the cupboards.
The switch is standard wall mounting, with back box. The switch started
to play up, not always supplying power, so yesterday, I replaced it.

The incoming power is standard grey sheathed T&E, and I rather suspect
comes as a spur from a nearby 13 amp socket. Live and return are red
and black. Power from switch to lights is ordinary flex, as you would
use with a table lamp, or similar, with modern colours - blue, brown
etc. The switch itself was a monstrous thing, obviously designed for
far more than a light. Possibly a cooker. Twin pole, plus substantial
earth connections.

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch. Switch itself is plastic, as is the back box. Have
I done anything slightly naughty, inadvisable or dangerous?

That doesn't sound as if you have done anything dodgy. But the original
installer...

Mike

On 23/03/2017 07:50, Graeme wrote:

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch. Switch itself is plastic, as is the back box. Have
I done anything slightly naughty, inadvisable or dangerous?


You could change the switch for a switched fused spur unit and put a 2A
fuse in it.

Bill

In message , Bill Wright
writes

You could change the switch for a switched fused spur unit and put a 2A
fuse in it.

That sounds like a perfect solution. Thanks.
--
Graeme

In message , Chris J Dixon
writes
Graeme wrote:

I changed the switch live.

Yet you still need to ask:

Have done anything slightly naughty, inadvisable or dangerous?

Well, yes, although I was really referring to the wiring, rather than
how I achieved it. Having said that, I was very careful, firstly
disconnecting the returns, one at a time, and joining via a chocolate
block, then same for the two earths.

Next, I removed the unpowered live return, and connected that to the new
switch, then finally the live feed, having used a meter to establish
that the switch was off. I used well insulated screwdriver and needle
nose pliers, carefully and slowly.
--
Graeme

On 23/03/17 10:16, Graeme wrote:
In message , Chris J Dixon
writes
Graeme wrote:

I changed the switch live.

Yet you still need to ask:

Have done anything slightly naughty, inadvisable or dangerous?

Well, yes, although I was really referring to the wiring, rather than
how I achieved it. Having said that, I was very careful, firstly
disconnecting the returns, one at a time, and joining via a chocolate
block, then same for the two earths.

Next, I removed the unpowered live return, and connected that to the new
switch, then finally the live feed, having used a meter to establish
that the switch was off. I used well insulated screwdriver and needle
nose pliers, carefully and slowly.

But you no doubt assumed the wiring was correct in the first place.
There's no guarantee of that, particularly as an obviously unsuitable
switch had been used in the first place, and you suspected connection
from a 13 amp spur. Why didn't you switch off or pull the fuse at the
box before working on it?

Just out of interest, did you know there if was a consumer unit with a
working rcd/elcb before you did any live work?

--

Jeff

In message , Jeff Layman
writes

But you no doubt assumed the wiring was correct in the first place.

I checked that the red was indeed live before starting.

Just out of interest, did you know there if was a consumer unit with a
working rcd/elcb before you did any live work?

Fuses only here.
--
Graeme

On 23/03/2017 07:50, Graeme wrote:
Simple enough job, usually.

We have a pair of 2ft florescent tubes under kitchen wall cupboards,
daisy chained and controlled by a switch within one of the cupboards.
The switch is standard wall mounting, with back box. The switch started
to play up, not always supplying power, so yesterday, I replaced it.

The incoming power is standard grey sheathed T&E, and I rather suspect
comes as a spur from a nearby 13 amp socket. Live and return are red
and black. Power from switch to lights is ordinary flex, as you would
use with a table lamp, or similar, with modern colours - blue, brown
etc. The switch itself was a monstrous thing, obviously designed for
far more than a light. Possibly a cooker. Twin pole, plus substantial
earth connections.

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch. Switch itself is plastic, as is the back box. Have
I done anything slightly naughty, inadvisable or dangerous?

Nope, what you have done is fine...

What was done before you got to it might be a problem - but that is not
your fault. If the source of the supply is a socket circuit, then it
should come from a fused connection unit somewhere. Otherwise the flex
to the lamps is unlikely to have adequate fault protection.

(note this is not huge danger since the chances of the flex getting
damaged in that installation scanrio is presumably vanishingly small,
and there are not many likely failure modes of the lamps that will
result in a hard short circuit)


--
Cheers,

John.

/================================================== ===============\
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|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 23/03/2017 10:10, Graeme wrote:
In message , Bill Wright
writes

You could change the switch for a switched fused spur unit and put a
2A fuse in it.

That sounds like a perfect solution. Thanks.

Only thing to check is that the T&E coming into it is of adequate size.

Chances are it is, however if you found for example that the circuit was
protected by a 30A BS3036 rewireable fuse, and the extension had been
done in 1mm^2 T&E, then that bit of T&E may not have fault protection
without the fuse at its origin rather than its end[1].

(still a tiny risk in absolute terms - it probably falls into the
category of stuff I would not do in the first place, but would only
bother fixing if there were other reasons to change stuff)


[1] i.e. this is a variation of the situation that can leave a spur
unprotected on installs with old 2.5mm^2 T&E that only had a 1mm^2 CPC.
(modern 2.5mm^2 T&E has a 1.5mm^2 earth)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Well, it all depends on whether the wires can be trusted on their sources
I'd say, assuming this, I think I'd feel happier if a fused spur was there
rather than a light switch with, say a 3 amp fuse in it.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Graeme" wrote in message
...
Simple enough job, usually.

We have a pair of 2ft florescent tubes under kitchen wall cupboards, daisy
chained and controlled by a switch within one of the cupboards. The switch
is standard wall mounting, with back box. The switch started to play up,
not always supplying power, so yesterday, I replaced it.

The incoming power is standard grey sheathed T&E, and I rather suspect
comes as a spur from a nearby 13 amp socket. Live and return are red and
black. Power from switch to lights is ordinary flex, as you would use
with a table lamp, or similar, with modern colours - blue, brown etc. The
switch itself was a monstrous thing, obviously designed for far more than
a light. Possibly a cooker. Twin pole, plus substantial earth
connections.

The new switch I installed is an ordinary wall light switch, single pole,
so I wired the two lives to that, and directly connected the two returns
and two earths using a chocolate block, tucked in the back box behind the
switch. Switch itself is plastic, as is the back box. Have I done
anything slightly naughty, inadvisable or dangerous?

--
Graeme

Bill Wright wrote in newsb05u9$1lhp$1
@gioia.aioe.org:

On 23/03/2017 07:50, Graeme wrote:

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch. Switch itself is plastic, as is the back box. Have
I done anything slightly naughty, inadvisable or dangerous?


You could change the switch for a switched fused spur unit and put a 2A
fuse in it.

Bill


+++++1

In message , John
Rumm writes
On 23/03/2017 10:10, Graeme wrote:
In message , Bill Wright
writes

You could change the switch for a switched fused spur unit and put a
2A fuse in it.

That sounds like a perfect solution. Thanks.

Only thing to check is that the T&E coming into it is of adequate size.

Thanks John. I'm no electrician (!) but it was the physical size of the
incoming T&E that first made me suspect it to be a spur from the power
rather than lighting ring main. It is what I would associate with a
power circuit rather than a lighting circuit.

Someone mentioned an ex cooker socket. No, not that heavy, and I know
exactly where the ex cooker cable terminates, even though it is no
longer in use.
--
Graeme

In message , John
Rumm writes

(note this is not huge danger since the chances of the flex getting
damaged in that installation scanrio is presumably vanishingly small,
and there are not many likely failure modes of the lamps that will
result in a hard short circuit)

My thoughts exactly. The flex supplying the lamps is there to inspect,
and easily seen, so I am confident that any damage would be noticed.
--
Graeme

On 23/03/2017 15:23, Graeme wrote:
In message , John
Rumm writes

(note this is not huge danger since the chances of the flex getting
damaged in that installation scanrio is presumably vanishingly small,
and there are not many likely failure modes of the lamps that will
result in a hard short circuit)

My thoughts exactly. The flex supplying the lamps is there to inspect,
and easily seen, so I am confident that any damage would be noticed.

As suggested earlier - if you have a large enough T&E coming in (which
by the sounds of it you do), then a switched FCU used as a switch will
do the job nicely.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thu, 23 Mar 2017 12:45:56 GMT, DerbyBorn
wrote:

Bill Wright wrote in newsb05u9$1lhp$1
:

On 23/03/2017 07:50, Graeme wrote:

The new switch I installed is an ordinary wall light switch, single
pole, so I wired the two lives to that, and directly connected the two
returns and two earths using a chocolate block, tucked in the back box
behind the switch. Switch itself is plastic, as is the back box. Have
I done anything slightly naughty, inadvisable or dangerous?


You could change the switch for a switched fused spur unit and put a 2A
fuse in it.

Bill


+++++1

One man - one vote :-)

One man - one vote :-)


Got a bit excited that the right answer eventually came!