On 21 May 2005 18:24:52 GMT, (Andrew
Gabriel) wrote:

I would strongly suggest crimping unless you are already expert at
electrical soldering (in which case you wouldn't have posted this
question). Crimping is much easier to get right and reliable (in
spite of the unjustified scare storey floating around here) starting
from an untrained position on either side and it is standard electrical
practice, whereas soldering isn't. Use insulated crimps and a proper
ratchet crimper, and do some practice runs.
I didn't notice the PVC becoming damaged, either expanding or melting. It
seemed to me to be as good as before. I'm just a little worried that it
might have melted and become compromised above/below the joint, where I
can't see. On the other hand, I've tested the sockets with devices that draw
large currents - if anything had gone wrong, I'd know about it, wouldn't I?

If you're asking someone here to tell you it's OK, no one can,
because no one saw you making the connection or inspected the
quality of it afterwards. If you are unsure, get an electrician
in to inspect it and possibly redo it and test the integrity of
the ring circuit.

While agreeing with all of Andrew's caveats, I'd add that you can adapt
a trick from electronics and use a pair of thin-nosed pliers on the wire
to act as a heat sink. In this case you're going to end up with two
pairs of pliers and the iron and the solder all to go in, so unless you
are an octopus you are going to need a friend, or some haemostatic
forceps.
--
On-line canal route planner: http://www.canalplan.org.uk

(Waterways World site of the month, April 2001)

I'm really, really sorry if I come across as labouring this point, but I
need some definitive advice on the best way of connecting two pieces of
ring-main T&E together.

Regular readers will know that I started off doing this with terminal blocks
but because these would have to be hidden behind plasterboard, either
soldering or crimping was the only way forward.

I chose soldering. I understand there are a couple of gotchs when doing
this:

- each join must be soldered ASAP because the PCV coating on the T&E will
start to melt; this can be a problem if there is a bend in the wire near the
soldering because the copper can "push through" the softened PVC so it
touches its neighbour

- bind the cables together to form a strong mechanical joint before
soldering; keep the solder light to merely enforce the joint.

With that in mind, this is what I did:

- twisted the cables together using pliers
- tinned the soldering iron
- heated the joint and flowed solder onto it

I used a gas-powered soldering iron because, obviously, the power was turned
off.

The joints I made seemed strong but didn't occur in just a few seconds - in
some cases I had to heat the joint maybe 30 seconds or more before it became
hot enough for the solder to melt onto it.

I didn't notice the PVC becoming damaged, either expanding or melting. It
seemed to me to be as good as before. I'm just a little worried that it
might have melted and become compromised above/below the joint, where I
can't see. On the other hand, I've tested the sockets with devices that draw
large currents - if anything had gone wrong, I'd know about it, wouldn't I?

Secondly, I wrapped the joints in electrical tape because I just couldn't
source heat shrink in time. Each joint was wrapped 3 or 4 times, and then
the whole thing was wrapped in more tape.

I *think* I've done this well enough. One final thing I might do is put the
joints inside fireproof boxes so that in the unlikely event of something
going wrong, they won't set the house on fire.

In article ,
"Brian" writes:
I'm really, really sorry if I come across as labouring this point, but I
need some definitive advice on the best way of connecting two pieces of
ring-main T&E together.

Regular readers will know that I started off doing this with terminal blocks
but because these would have to be hidden behind plasterboard, either
soldering or crimping was the only way forward.

I chose soldering. I understand there are a couple of gotchs when doing
this:

I would strongly suggest crimping unless you are already expert at
electrical soldering (in which case you wouldn't have posted this
question). Crimping is much easier to get right and reliable (in
spite of the unjustified scare storey floating around here) starting
from an untrained position on either side and it is standard electrical
practice, whereas soldering isn't. Use insulated crimps and a proper
ratchet crimper, and do some practice runs.

- each join must be soldered ASAP because the PCV coating on the T&E will
start to melt; this can be a problem if there is a bend in the wire near the
soldering because the copper can "push through" the softened PVC so it
touches its neighbour

- bind the cables together to form a strong mechanical joint before
soldering; keep the solder light to merely enforce the joint.

When I solder connections, I use a regular junction box in the
normal way to provide the enclosure and mechanical support just it
would normally be used, and then solder the terminal connections and
conductors together additionally afterwards. However, this can't be
said to be standard practice, because as I said before, soldering
isn't standard practice (although it is permitted) -- electricians
are not taught how to do it.

With that in mind, this is what I did:

- twisted the cables together using pliers
- tinned the soldering iron
- heated the joint and flowed solder onto it

I used a gas-powered soldering iron because, obviously, the power was turned
off.

The joints I made seemed strong but didn't occur in just a few seconds - in
some cases I had to heat the joint maybe 30 seconds or more before it became
hot enough for the solder to melt onto it.

I didn't notice the PVC becoming damaged, either expanding or melting. It
seemed to me to be as good as before. I'm just a little worried that it
might have melted and become compromised above/below the joint, where I
can't see. On the other hand, I've tested the sockets with devices that draw
large currents - if anything had gone wrong, I'd know about it, wouldn't I?

If you're asking someone here to tell you it's OK, no one can,
because no one saw you making the connection or inspected the
quality of it afterwards. If you are unsure, get an electrician
in to inspect it and possibly redo it and test the integrity of
the ring circuit.

--
Andrew Gabriel

quality of it afterwards. If you are unsure, get an electrician
in to inspect it and possibly redo it and test the integrity of
the ring circuit.

How would he/she go about testing the integrity of the circuit? Do you mean
continuity?

"Brian" wrote in message
...
I'm really, really sorry if I come across as labouring this point, but I
need some definitive advice on the best way of connecting two pieces of
ring-main T&E together.

Regular readers will know that I started off doing this with terminal
blocks
but because these would have to be hidden behind plasterboard, either
soldering or crimping was the only way forward.



I used a gas-powered soldering iron because, obviously, the power was
turned
off.

The joints I made seemed strong but didn't occur in just a few seconds -
in
some cases I had to heat the joint maybe 30 seconds or more before it
became
hot enough for the solder to melt onto it.


Just how big (or small) is this gas iron. Having done electical soldering
many years ago, if it didn't work in a couple of seconds and run the solder
over the joint, I would have given up.
For 13A cable a 50W electric iron with a fairly heavy 1cm diam bit minimum
is needed, preferably 1.5 cm. A 15W electronic iron would be far too small
and its small heat capacity would mean the wires cooled the bit to below
solder melting point, which is what seems to be happening.

rusty

snip

I would strongly suggest crimping unless you are already expert at
electrical soldering (in which case you wouldn't have posted this
question). Crimping is much easier to get right and reliable (in
spite of the unjustified scare storey floating around here) starting
from an untrained position on either side and it is standard electrical
practice, whereas soldering isn't. Use insulated crimps and a proper
ratchet crimper, and do some practice runs.

I would second that - much easier and reliable

Mike

In article ,
"Brian" writes:
quality of it afterwards. If you are unsure, get an electrician
in to inspect it and possibly redo it and test the integrity of
the ring circuit.

How would he/she go about testing the integrity of the circuit? Do you mean
continuity?

There's a standard way to test the integrity of a ring circuit
(a google search of this newsgroup will turn it up, or you can
find it in the On-Site Guide or the Inspection and Testing notes
book to supplement the Wiring Regs). Basically, the resistance of
the live and neutral loops are checked to be the same, and the
CPC to be as expected, and a check for cross-connected ring is
performed. The resistance is ideally measured using a high
current low voltage source, to tease out bad connections (which
a bog standard multimeter can easily miss).

--
Andrew Gabriel

In article , Brian
writes

With that in mind, this is what I did:

- twisted the cables together using pliers
- tinned the soldering iron
- heated the joint and flowed solder onto it
Sounds good.

I used a gas-powered soldering iron because, obviously, the power was turned
off.
Do you only have one ring?, handy to have 2 for just such an occasion as
this, also this would be on of the few acceptable situations to use an
electric iron wired up to a lighting circuit adaptor.

The joints I made seemed strong but didn't occur in just a few seconds - in
some cases I had to heat the joint maybe 30 seconds or more before it became
hot enough for the solder to melt onto it.
Ok, 30s is way too long, if you haven't made the joint in 5s then your iron
isn't powerful enough and you risk overcooking the joint/insulation. The
irons I would use for something like this are 60 or 45w temperature
controlled irons fitted with a large tip but I could probably make the joint
adequately with as standard (cheapie) 25W item. As wire is cheap you
can practice making these joints all day until you've got it right, then move
over and do it on the critical joint.

I didn't notice the PVC becoming damaged, either expanding or melting. It
seemed to me to be as good as before. I'm just a little worried that it
might have melted and become compromised above/below the joint, where I
can't see. On the other hand, I've tested the sockets with devices that draw
large currents - if anything had gone wrong, I'd know about it, wouldn't I?
The problem with overcooking the work is less likely to be in the current
carrying capacity of the joint but in the integrity of the insulation which may
break down after a few years of ageing, not something you would want to
have buried in the wall.

Secondly, I wrapped the joints in electrical tape because I just couldn't
source heat shrink in time. Each joint was wrapped 3 or 4 times, and then
the whole thing was wrapped in more tape.
Not really a good plan as insulation tape ages, its adhesive fails and the
wrap loosens, not the best for the long term. That said, many hundreds of
thousands of houses in the uk have hidden chocolate block joints
(sometimes) wrapped in insulation tape which have not caused problems.
It just seems a shame to start doing the best possible job you can, then
skimp on the details. Personally I use adhesive lined heatshrink on all my
joints, that way it stays where it is put and offers additional strain relief.

I *think* I've done this well enough. One final thing I might do is put the
joints inside fireproof boxes so that in the unlikely event of something
going wrong, they won't set the house on fire.
Nope, if you aren't confident in the job, use a 'pro', HA! there's a laugh, 4/5
would probably twist the wires, wrap it in insulation tape & bury it ;-)

As other have said, no-one can say authoritatively that your joint is good
so it may be worthwhile remaking it after a bit of soldering practice and
using the right sort of insulation.

Btw, my preference is still for soldering over crimping, I've seen too many
badly made joints caused by operator error in choice of crimp and/or tool
setting just waiting for long term failure but that's just my experience.

I'm sure this sounds like a lecture, its not meant to, good luck :-)
--
fred

Two risks on the critical path...
o Connection
---- failure can cause local-heating or MCB/RCD trip
---- failure on a ring is 1) not obvious & 2) can result in 2.5T&E carrying 32A
o Insulation
---- failure can cause local-heating or MCB/RCD trip
---- failure can cause a N to E link, triping RCD & non-isolatable by MCB

Soldering involves both soldering & insulating tape risk.
o Tape seems to unwind -- not convinced about decadal cold-flow
o Soldering requires speed -- PVC insulation *continuous* rating of 60oC

Crimping involves single ratchet tool risk (insulating crimps proven).
o Crimping practice -- pull-apart test & inspect insulation

Surprised there isn't a simple kit...
o Simple barrel crimps tightly matched to solid core o.d. intervals
o Micro LNE-divided housing + bit of pourable epoxy, velcro for the cat

You can get heatshrink-insulating-crimps re extra mechanical strength.
Do not consider using cheap-n-cheesy stamped-bar crimp tools.
--
Dorothy Bradbury

Nick Atty wrote:


While agreeing with all of Andrew's caveats, I'd add that you can adapt
a trick from electronics and use a pair of thin-nosed pliers on the wire
to act as a heat sink.

I originally heard this back when I was in short trousers and dropping
solder on my legs in the late 60's and had my doubts it did any good
as designs using fragile germanium devices were soldered ok.

Progressing onto circuit design, development, and repair of industrial
control and communications equipment from the late 70's to the mid
90's I, along with all my colleagues, never saw ANY advantage in using
a heat shunt - fast and quick with, if necessary post transition rapid
cooling is the way to go - a heat shunt always, without exception,
slows down the process and increases the heat input from the iron that
is required to get the joint and solder up to flow temperature. Apply
it after the solder has flowed and there may be some slight advantage
but a slight wait for the transition followed by freezer spray does
just a good if not a better job and can be applied much quicker than a
heat shunt.

We regularly soldered the smallest leaded components with temperature
controlled 50W soldering irons, even a tiny 2.5mm x 1 mm detector
diode in a spectrum analyser costing 350 quid was soldered like this
(albeit with a nervous hand). Later on surface mount components were
done this way until we got our infra red rework unit and hot air
reflow guns. Our repairs were tracked for many years (certainly to my
knowledge until post 2002) and failure rates post repair were
extremely low.


--

In message ,
andrew@a17 (Andrew Gabriel) wrote:

In article ,
"Brian" writes:
quality of it afterwards. If you are unsure, get an electrician
in to inspect it and possibly redo it and test the integrity of
the ring circuit.

How would he/she go about testing the integrity of the circuit? Do you mean
continuity?

There's a standard way to test the integrity of a ring circuit
(a google search of this newsgroup will turn it up, or you can
find it in the On-Site Guide or the Inspection and Testing notes
book to supplement the Wiring Regs). Basically, the resistance of
the live and neutral loops are checked to be the same, and the
CPC to be as expected, and a check for cross-connected ring is
performed. The resistance is ideally measured using a high
current low voltage source, to tease out bad connections (which
a bog standard multimeter can easily miss).


Not forgetting an insulation resistance test (high voltage) which might
be more illuminating in this case as the OP is worried he might have
damaged the insulation, or that his tape-wrapped joints are not good
enough.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... He's got a magnet!!! Everybody BACKUP!!!!!!!!

On Sat, 21 May 2005 21:50:16 GMT, "Dorothy Bradbury"
wrote:

snip of understood pros/cons

o Micro LNE-divided housing + bit of pourable epoxy, velcro for the cat

Ok - you lost me on the last claws - ???

Geo

Do you only have one ring?, handy to have 2 for just such an occasion as
this, also this would be on of the few acceptable situations to use an
electric iron wired up to a lighting circuit adaptor.

No, just one ring. I don't have friendly neighbours. A 50W iron would
(according to my calcs) require an extension cable of handling around 5
amps. I don't have one of these.

Ok, 30s is way too long, if you haven't made the joint in 5s then your
iron
isn't powerful enough and you risk overcooking the joint/insulation. The

Well, it's done and, if what you say is true, I'm well and truly f***ed. The
joints have been made and if the insulation has been damaged then it's
damaged forever. It's hard to describe the situation but the solder joints
were made just after the T&E comes out of a concrete-cladded wall. In other
words, I can't cut back and start further up.

The problem with overcooking the work is less likely to be in the current
carrying capacity of the joint but in the integrity of the insulation
which may
break down after a few years of ageing, not something you would want to
have buried in the wall.

Tell me truthfully - is this something that *really* happens in real life?
I'm not being trite - I really want to know. Does anybody have any actual
experience of it happening?

As other have said, no-one can say authoritatively that your joint is good
so it may be worthwhile remaking it after a bit of soldering practice and
using the right sort of insulation.

I've got some small experience of soldering and consulted a pal, and I'm
sure that the joints are good enough, both mechanically and in terms of
soldering. The ring main is almost certainly functioning correctly.

However, the problem is whether I've left a serious problem for future
owners of this house by

a) using electrical tape to cover the joints (answer: yes)
b) degrading the insulation to the extent where it will catastrophically
fail in a few years' time.

I think my only real solution is to put these joints into blank socket boxes
accessible to anybody, so at least a future electrician can open them up and
discover what's been done. This will look ugly (the joints are at head
height), but I guess I can strategically hang some pictures over the boxes
when it comes to sell the house.

I'm sure this sounds like a lecture, its not meant to, good luck :-)

Lectures are sometimes needed for those of us with more enthusiasm than
experience, and your help is received with thanks.

On Sun, 22 May 2005 09:23:04 +0000 (UTC), Brian wrote:

No, just one ring. I don't have friendly neighbours. A 50W iron
would (according to my calcs) require an extension cable of handling
around 5 amps. I don't have one of these.

eh? P = VI so the power from 5A is 230 * 5 = 1150W.

Rearranging the above formula gives P/V = I or 0.2 and a bit amps for
50W. I think you did V/P. B-)

--
Cheers
Dave. pam is missing e-mail

o Micro LNE-divided housing + bit of pourable epoxy, velcro for the cat

Ok - you lost me on the last claws - ???

After a paws for thought, just use a quick setting epoxy :-)
--
Dorothy Bradbury

On Sat, 21 May 2005 13:36:14 +0100, Nick Atty
wrote:

On 21 May 2005 18:24:52 GMT, (Andrew
Gabriel) wrote:

I would strongly suggest crimping unless you are already expert at
electrical soldering (in which case you wouldn't have posted this
question). Crimping is much easier to get right and reliable (in
spite of the unjustified scare storey floating around here) starting
from an untrained position on either side and it is standard electrical
practice, whereas soldering isn't. Use insulated crimps and a proper
ratchet crimper, and do some practice runs.
I didn't notice the PVC becoming damaged, either expanding or melting. It
seemed to me to be as good as before. I'm just a little worried that it
might have melted and become compromised above/below the joint, where I
can't see. On the other hand, I've tested the sockets with devices that draw
large currents - if anything had gone wrong, I'd know about it, wouldn't I?

If you're asking someone here to tell you it's OK, no one can,
because no one saw you making the connection or inspected the
quality of it afterwards. If you are unsure, get an electrician
in to inspect it and possibly redo it and test the integrity of
the ring circuit.

While agreeing with all of Andrew's caveats, I'd add that you can adapt
a trick from electronics and use a pair of thin-nosed pliers on the wire
to act as a heat sink. In this case you're going to end up with two
pairs of pliers and the iron and the solder all to go in, so unless you
are an octopus you are going to need a friend, or some haemostatic
forceps.

I think you can also get putty that takes the heat away .
Stuart






Shift THELEVER to reply.

Brian wrote:

With that in mind, this is what I did:

- twisted the cables together using pliers
- tinned the soldering iron
- heated the joint and flowed solder onto it

I used a gas-powered soldering iron because, obviously, the power was turned
off.

The joints I made seemed strong but didn't occur in just a few seconds - in
some cases I had to heat the joint maybe 30 seconds or more before it became
hot enough for the solder to melt onto it.


I would say there is a pretty good chance you have a decent joint - the
fact the wires were twisted together first will probably ensure that (I
have uncovered enough "permanent" joins made like that without solder in
peoples houses in the past!

I *think* I've done this well enough. One final thing I might do is put the
joints inside fireproof boxes so that in the unlikely event of something
going wrong, they won't set the house on fire.

The soldering iron you used sounds like it was too small or needed a
bigger bit on it. An insulation resistance check at high voltage ought
to put your mind at rest however.

(personally I would have used crimps)



--
Cheers,

John.

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

In article , Nick Atty
wrote:

While agreeing with all of Andrew's caveats, I'd add that you can adapt
a trick from electronics and use a pair of thin-nosed pliers on the wire
to act as a heat sink. In this case you're going to end up with two
pairs of pliers and the iron and the solder all to go in, so unless you
are an octopus you are going to need a friend, or some haemostatic
forceps.

Elastic bands holding the pliers shut works for me.

--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

Do NOT solder T&E.

The only soldering an electrician will do is to add bonding in an innaccessible place. This is on single-core wire, so melting of the sheath is not as much of an issue, and it will be soldering/brazing direct to a copper pipe.

Why not extend the ring properly?

If you must add a spur, you are allowed under regulations to take it from the socket.

FAILING THAT - BUY A JUNCTION BOX - IT'S WHAT THEY'RE FOR.

About £2.50 for a 30Amp box.

On Tue, 24 May 2005 16:58:24 UTC, state-it
wrote:

FAILING THAT - BUY A JUNCTION BOX - IT'S WHAT THEY'RE FOR.

As usual, take posts from diybanter with a pinch of salt.

The OP said the joint would be inaccessible - and that is NOT what
junction boxes are for.

If you can't get it right, don't post.

--
Bob Eager
begin a new life...take up Extreme Ironing!

state-it wrote:

Why not extend the ring properly?

If you read from the start of the thread you will see that is exactly
what the OP is doing.

If you must add a spur, you are allowed under regulations to take it
from the socket.

True, but not relevant in this case.

FAILING THAT - BUY A JUNCTION BOX - IT'S WHAT THEY'RE FOR.

No not always. When you need to join a cable that will be inaccessible
later (i.e. plastered over) the regs do not allow the use of screw
terminal joins. You can crimp, solder, braze, or weld.



--
Cheers,

John.

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