Dear me .. nothing's ever simple! All I wanted to do was take a fused spur
from the ring mains where the switch for my boiler was so that I could power
a light ....

I opened the "junction box" there and found it was a chocolate box strip of
6 blocks, with loads of what looks like 1mm cabling (I say looks like
because I only tend to use 1.5 or 2.5mm). Really flexible stranded stuff
rather then solid core. There are 5 of these T&E cables coming in.

I'm slightly confused however as to just what I'm looking at. All of the
neutrals are connected in one block, but the earths and lives are in a
varied configuration that's hard to follow (access beside the boiler is
difficult and there's not a lot of slack in the wires). When I turn the
switch for the boiler off, none of the cables are live any more. When I
turn it on, two of the blocks are. Does this mean that the entire thing is
just a switched spur? A cable also comes out of this junction to the
heating controller unit, which accounts for two (along with the boiler
switch).

Out of the other 3 cables, two come up from under the floor together and the
other disappears into the wall behind. Don't have access to find out any
more about their onward journeys!


What can I do here? My intention was (assuming this was a normal junction
box), to add in a 2.5mm T&E spur to the junction to my fused box, then run
1.5mm T&E from that to the light switch.



a

"al" wrote in message
k...
Dear me .. nothing's ever simple! All I wanted to do was take a fused
spur from the ring mains where the switch for my boiler was so that I
could power a light ....

I opened the "junction box" there and found it was a chocolate box strip
of 6 blocks, with loads of what looks like 1mm cabling (I say looks like
because I only tend to use 1.5 or 2.5mm). Really flexible stranded stuff
rather then solid core. There are 5 of these T&E cables coming in.

I'm slightly confused however as to just what I'm looking at.

Put the cover back and find a different connection point.

The power feed is unlikely to have to have much capacity as it should be off
a fused unit somewhere and is probably fused at 3A or so.

The cables will have connections that include:

boiler on (input)
HW on (output)
Heating on (output)
pump (output)
mains (input)


They should be labelled (mine aren't either).

al wrote:
Dear me .. nothing's ever simple! All I wanted to do was take a
fused spur
from the ring mains where the switch for my boiler was so that I
could power
a light ....

I opened the "junction box" there and found it was a chocolate box
strip of
6 blocks, with loads of what looks like 1mm cabling (I say looks like

because I only tend to use 1.5 or 2.5mm). Really flexible stranded
stuff
rather then solid core. There are 5 of these T&E cables coming in.

I'm slightly confused however as to just what I'm looking at. All of
the
neutrals are connected in one block, but the earths and lives are in
a
varied configuration that's hard to follow (access beside the boiler
is
difficult and there's not a lot of slack in the wires). When I turn
the
switch for the boiler off, none of the cables are live any more.
When I
turn it on, two of the blocks are. Does this mean that the entire
thing is
just a switched spur? A cable also comes out of this junction to the

heating controller unit, which accounts for two (along with the
boiler
switch).

Out of the other 3 cables, two come up from under the floor together
and the
other disappears into the wall behind. Don't have access to find out
any
more about their onward journeys!


What can I do here? My intention was (assuming this was a normal
junction
box), to add in a 2.5mm T&E spur to the junction to my fused box,
then run
1.5mm T&E from that to the light switch.



a



Very carefully put the cover back on the junction box and hope you have
not disturbed any cables in it.

What you have found is the wiring centre for your heating system, with
wires going off to the room stst, tank stat, motorised valves, time
clock, pump, boiler and any thing else that might control your heating
system.

As you noticed the neturals and earths are joined in there resptive
connectors all the other cables will be LIVE at some point in the
heating cycle what ever colour the cable may be.

One crossed wire or one broken wire = no heating or hot water and a
possible high bill to sort the problem.

I would strongly recamend you take your spur from some other point on
your ring.

David.

"d." wrote in message
Very carefully put the cover back on the junction box and hope you have
not disturbed any cables in it.

What you have found is the wiring centre for your heating system, with
wires going off to the room stst, tank stat, motorised valves, time
clock, pump, boiler and any thing else that might control your heating
system.

As you noticed the neturals and earths are joined in there resptive
connectors all the other cables will be LIVE at some point in the
heating cycle what ever colour the cable may be.

One crossed wire or one broken wire = no heating or hot water and a
possible high bill to sort the problem.

I would strongly recamend you take your spur from some other point on
your ring.


Damn, damn, damn and quadruple damn! Too late to move my spur now, will
have to plaster it in and paper over. Going to have to try and take up the
floor underneath and extend down there.

As an aside - is it normal to use such low rated wire for all of these
c.heating elements? Seems like the type you'd find inside a hairdryer!



a

"dennis@home" wrote in message
news:wkZje.37053
The power feed is unlikely to have to have much capacity as it should be
off a fused unit somewhere and is probably fused at 3A or so.

There is a fused box beside it, quite possibly 3A (intelligently placed
where it's next to bloody possible to get the fuse out, so I ain't gonna
play with it now just to find out its rating!).

Shouldn't the spur feeding it all be in 2.5mm cable though ... ie. before
the fuse?





a

As an aside - is it normal to use such low rated wire for all of these
c.heating elements? Seems like the type you'd find inside a hairdryer!

Yes, CH takes very little current, its usually done in 1mm T&E.

Dave

"dave stanton" wrote in message
news

As an aside - is it normal to use such low rated wire for all of these
c.heating elements? Seems like the type you'd find inside a hairdryer!

Yes, CH takes very little current, its usually done in 1mm T&E.


*dreams of a world where he could knock his house down and start from
scratch* ......




... sigh


a

On Sun, 22 May 2005 15:53:25 +0000, al wrote:

"dave stanton" wrote in message
news

As an aside - is it normal to use such low rated wire for all of these
c.heating elements? Seems like the type you'd find inside a hairdryer!

Yes, CH takes very little current, its usually done in 1mm T&E.


*dreams of a world where he could knock his house down and start from
scratch* ......

And no Part P either......

Dave

"al" wrote in message
k...
"dennis@home" wrote in message
news:wkZje.37053
The power feed is unlikely to have to have much capacity as it should be
off a fused unit somewhere and is probably fused at 3A or so.

There is a fused box beside it, quite possibly 3A (intelligently placed
where it's next to bloody possible to get the fuse out, so I ain't gonna
play with it now just to find out its rating!).

Shouldn't the spur feeding it all be in 2.5mm cable though ... ie. before
the fuse?


Normally yes.
(But it doesn't have to be if an appropriate breaker is fitted in the
circuit (e.g. in the consumer unit)).

It may be an appropriate place to take another feed from.

"dennis@home" wrote in message
news:cA2ke.37245
Shouldn't the spur feeding it all be in 2.5mm cable though ... ie. before
the fuse?

Normally yes.
(But it doesn't have to be if an appropriate breaker is fitted in the
circuit (e.g. in the consumer unit)).

It may be an appropriate place to take another feed from.

Where? The 1mm T&E that comes up to the fuse for the C.H.? Seems a little
dodgy? Or do you mean look under the floor below it and see if it's a spur
from the ring main? Consumer unit's nowhere near the kitchen if you meant
to take a feed from there ..



a

As an aside - is it normal to use such low rated wire for all of these
c.heating elements? Seems like the type you'd find inside a hairdryer!

Yes. 1mm cable is good for many times the 3A the central heating will be
fused at, although it is probably 0.75mm or thicker flex, which will also be
fine for those currents.

Christian.

"dennis@home" wrote in message
news:cA2ke.37245
Shouldn't the spur feeding it all be in 2.5mm cable though ... ie. before
the fuse?

Normally yes.
(But it doesn't have to be if an appropriate breaker is fitted in the
circuit (e.g. in the consumer unit)).

It may be an appropriate place to take another feed from.

Aha ... damn hidden cables! Took the cover off the fuse unit (by the
boiler, not the CU) and found a 2.5mm T&E feeding it. Real pig to get to -
had to reach about 50cm down the side of the boiler (the gap to the wall
beside it being about the length of a normal electrical screwdriver!).

I did not enjoy that little piece of wiring. It was a hot enough day
already and the boiler had just been on, so really sweating buckets leaning
over it and reaching down along it! SERIOUSLY awkward getting the new 2.5mm
T&E spur cabled up to the feed. That stuff can be pretty damned inflexible
when it wants to!

Anyway, as originally intended, that new spur now comes into a 3A fuse box,
with 1.5mm T&E running up to the light switch and again the rest of the way
to the light fitting. Let there be light ......!

Thanks for all the help from everyone.




a