They were never popular here for mains wiring (at least, when
compared with US). I have a few UK wiring books going back to
about 1930, and they aren't used during that period for mains.
There is something which looks similar but actually contains a
blind brass terminal with a grub screw in the side, and that
seems to have been popular in that era. There's also something
else today which looks similar and made me do a double-take on
a couple of occasions, and that's a blind (one-sided) crimp.
They were popular for things like aerial, bell, speaker, etc
connections, and you can still buy them for that sort of use.
Of course, you will sometimes find someone has put one on
mains wiring. I moved into a house in 1986. It had been
professionally rewired in 1974 to a good standard, but then
less professionally modified in a couple of places, probably
in 1984. After about a year, a socket in the kitchen stopped
working. When I came to strip out the kitchen, I found that
the neutral was connected to where the socket had been before
moving it with a wirenut, which had burned out. So that was
installed in about 1984, and looked new, but didn't conform.
You will undoubtedly find such cases going all the way back
to their invention, probably more so when regs were less
strict, but they don't seem to have been in use for mains
back to at least 1930.
[email address is not usable -- followup in the newsgroup]
I'm not aware of any connection boxes explicitly designed for
soldering. Very few electricians are competent to solder, so
there would be no market for them.
17th edition doesn't tell you how to solder, crimp, or braze
connections. It's covered by requirement for good workmanship.
I will however comment on the special inaccessible connection
terminals which have sprung up. They seem to me to be to be completely
unsuitable for the job, indeed much worse than using screw terminals.
It's as though the designer didn't understand _why_ inaccessible
connections are specified to be handled differently, but just
designed something which doesn't use screw terminals because he
knew they aren't allowed. I've only seen pictures though, not had
one in my hands.
[email address is not usable -- followup in the newsgroup]
Only problems I've ever seen with screw terminals on a domestic
installation is where others have done them up - or rather not. I've never
had any come loose or give problems so personally would be perfectly happy
having an ordinary JB in a totally inaccessible place.
*Always remember you\'re unique, just like everyone else.
Dave Plowman firstname.lastname@example.org London SW
dangerous advice. Soldering works fine, but has one weakness that
catches people out: the solder is very soft and weak, and cant
tolerate movement. It is therefore essential that the wires to be
soldered are completely immobilised. You cant achieve that by wrapping
them with fusewire, twisting is the logical thing - BUT - twist them
twice as long as looks solid, else they're liable to fail.
TBH if you need instructions on soldering, dont do it. Its a fine
method if done right, but its so easy to screw up and leave a
dangerous joint behind. I've seen so many failures, thankfully at low
After serious thinking email@example.com wrote :
I agree that solder cannot tolerate movement, which was why I suggested
binding them with wire rather than twisting.
Trying to twist a single solid core would harden the copper making the
joint weaker, plus produces extra stress where the joint ends - than
leaving the cores straight and over binding plus soldering. There was
nothing dangerous in the advice, I have done it successfully many times
and it is a standard method used for many decades.
In the 1960's there was an IEE regulation taught method of solder
jointing the then used 7/.029 cable. It involved binding the two ends
then tinning at two points along the length of the joint, rather than
tinning the entire length. It was fairly similar to a splice in a rope.
The point being to provide a joint which was not only sound, but had
some built in flexibility.
On Mon, 11 May 2009 23:47:14 +0100, Dave Plowman (News) wrote:
Can't say I've been aware of plain twisted wires. Solder tag blocks, block
terminals with screws, IDC, gel filled IDC "nuts".
Wire wrapping I guess but that didn't seem to last long or become
widespread, I wonder why? B-)
On Tue, 12 May 2009 10:10:16 +0100 (BST), "Dave Liquorice"
Twisted joints were in use by the GPO for _many_ years in underground
cables - no doubt millions of such joints are still extant.
Indeed, long before that, twisted joints in various forms (Britannia
and copper-sleeve) were in use for overhead open wire spans.
Considerably more skill (and time) is needed to perform a twisted
joint than crimps and other 'modern' types.
Thanks John, this is exactly the way I would have tackled it, being an
electronics engineer. However what concerned me is that the heatshrink
sleeving is normally very thin, certainly much thinner than the cable
sheath. I'm concerned that this would fail an electrical inspection.
Heatshrink IME is a little thinner - but also a bit tougher. It
certainly withstands 500V testing with an insulation resistance tester.
If you are particularly concerned there is nothing to stop you using two
layers. The main thing is to ensure the joint itself does not have any
sharp protrusions like wisps of solder or wire ends poking out.
Presumably if you are soldering, then it is in a place where it can't be
inspected in future anyway!
I always use 60/40 tin/lead solder. Something with a flux core, and a
eutectic melting profile. I usually get a fairly fine solder for
electronics work (say 22 swg) and hence would use that - however if I
were buying it for the purpose, then would go for a heavier gauge.
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