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