It can be a bit hit-and-miss  ensuring that both wires are properly clamped in the same hole if you just insert them, doubled or no.  May be OK when installed but give problems later, and of course if one of the connections is not made you wouldn’t necessarily ntice but it would affect the “diversity” of the ring main.  My vote would be to twist them if you can.  The Wago clips sound like a good idea for new sockets.

I agree with John. A quality branded socket with spring clamps (two holes each for live, neutal and earth) removes the skill factor.
Years agow I was taught to twist the two wires. This has fallen out of favor as it takes more time, If it’s a ring with two wires put them straight, single wire fold it in two. This allows the screw to set into the “V” between two wires in each case.

Robert.

On 22 January 2026 at 12:23 Engine Builder Said:

45 years as an electrician, Do not twist. Assuming solid conductors, fold them back to increase the size and fill the terminal.

 

This is what I’ve seen in my last two houses and also online recently. In my earlier properties I saw quite a few twisted cables though.

Edit: Some time ago I fitted a Crabtree cooker socket and it had wire clamps that bore down on the cable rather than direct contact with the screws. This seemed like a better idea to me. Sadly not always very easy to get Crabtree stuff locally.

A sparkie friend gave me a good tip: re-tighten the terminal screws after having wrestled the socket onto/into its box. (Pull it out just enough to access the screws, of course.) The unavoidable tight bending of the conductors as the socket is pushed into position puts enough strain on them to loosen the screws’ grip. Experience confirms.

On 23 January 2026 at 01:14 howardb Said:

Does anybody have any idea why the UK persists with specifying and using square socket back boxes?

Is it a case of “we’ve always done it this way” or some other criteria?

Well as most socket faceplates are rectangular or square it makes sense and gives more room for wiring etc. North america also use square or rectangular. Another question is why do mainland europe use round? Even the twin outlets tend to have rouned ends on the back boxes. The probable answer is its easier to make the hole, you just need a hole saw.

Robert.

On 23 January 2026 at 09:13 Engine Builder Said:

On 23 January 2026 at 00:14 Vic Said:

On 22 January 2026 at 12:23 Engine Builder Said:

45 years as an electrician, Do not twist. Assuming solid conductors, fold them back to increase the size and fill the terminal.

 

This is what I’ve seen in my last two houses and also online recently. In my earlier properties I saw quite a few twisted cables though.

 

Sounds like your installation was done by a qualified electrician, not one following the incorrect advice given by other menbers here.

Solid cores should never be twisted together.

Can you explain what the incorrect advice being given by members is?  People are reporting twisted wires, presumably installed by qualified electricians. I’m not seeing advice other than your “don’t twist”.

Where does “don’t twist” come from?  Is there a reference?  I’m not an past or present trained electrician, but an advantage of twisting is that it ensures continuity of the ring even if the screw terminal comes loose.  When parallel wires are inserted continuity depends on the terminal screw staying tight, and they don’t always.  Could cause a fire…   What does BS 7671 say?

In other fields ferrules are preferred to twisting and pairing!  Are ferrules ever applied to ring main sockets? I don’t know…

Dave

Where does “don’t twist” come from?

I have heard a wire having broken where the screw has come down onto the wire where it passed over the other wire in a twist.

This thread seems to confirm my experience.

https://www.electriciansforums.net/threads/twist-or-no-twist.194905/

There are dozens of pages on twist or not on the electricians forums. That is all just opinion. No formal guidance.
I stand by my earlier comment. Twisting was the old way and still OK. Discontinued mainly because of time taken. Nothing wrong with it.

I will add another reason for it falling out of favour – the introduction of regular testing of installations. Some of the tests require the ring to be broken which is harder with twisted wires.

You should not untwist / retwist wires “just to check”.
Sockets that use cages, leafs or spring clamps are much better as there is no rotating screw contacting the wire and damaging it.

Robert.

On 23 January 2026 at 20:51 Engine Builder Said:

When I started my aprenticeship back in the late 60s cables for socket circuits had stranded cores and were imperial sizes e.g 7/029 was 7 strands of .029″ area copper. Convention was the 7 strands should be twisted to form a solid core.  When cables changed to metric sizes the cables had a single solid condutor and the cable manufactures advice was not to twist. I would suggest any instalation you have where solid core cable have been twisted together have not been done by a compedent electrician.

Hi, yes, in older days the early twin & earth were stranded, and twisting them even on a radial system, made it much easier to get then into the socket holes, as otherwise, very often if you left them strait you would often get one or two strands snag on the edge of the hole and would end up outside of it, and if it was in a tight place, made it even harder, and things were worse on a ring main in getting two straight stranded wires into one hole. Photo below shows a 13A single socket with stranded 3mm sq’ twin & earth, which went through a wall to another 13A socket, to join a radial twin & earth, but I suspect the two sockets were originally the old 15A round pin type. this was a disconnected line which was just left in place during a complete rewire before I live here, and I removed it all, as the twin and earth was fixed to the top of the skirting board, but some of it was hanging adrift so it all had to come off.

Regards Nick.

Solid copper progressively collapses and runs away from the clamp load. Single strand pushed in will work loose over time. Won that argument with a sparky type ages ago by getting him to put a single wire in a spare socket, presumably a decent one as it was left over from a job he done, as a test object telling him we’d look at it in three years.

Passed the pull-out test when done.

Three years later slid out quite easily!

I suspect that after 5 the wire would have been just lying there with no clamp pressure. Which wouldn’t have boded well for a real connection. I’ve pulled a few old faceplates off and left the wire behind when helping folk out on weekend / evening emergencies. Something I avoid as much as possible but sometimes you have to step in. I’ve noticed that the connections in modern sockets don’t grip as well as the old style ones. Contact area on switches can be pretty pathetic too.

I’ve always used the U bend technique which gives much more area for the screw to contact meaning less load and less flow. Never seen one of mine come loose. U bend also gives more contact between a pair of wires. I also arrange enough slack so the faceplate folds out flat making it far easier to wire in. When I had my extension done I was surprised that a very experienced sparky, who’d done work before, hadn’t shown his new guy “apprentice” the fold’n shape technique. Very strange as I’d shown him 20 years before.

Twisting does increase the contact area and reduces the load as the twists come down against each other as the connection is more secure. The risk with twisting is that the wire may be partially work hardened and snap. Either during twist or if the wire is jogged or manipulated after insertion. Had to replace one of those cheap’n nasty plastic box choc-block style joiners hidden in a cupboard when the trailing, tested together, wires had been jogged by accident. OK total bodge by whoever put it in. Wrong type of connector, cable clamps not done up and no wiring clips so it would have come out a New York minute after I’d gotten a proper junction box anyway. But you don’t expect the wire to snap.

Clive