70's wiring in new sockets

[sxturbo]

Further to a thread that someone was asking whether to extend the ring or adding a spur on a 70's house and it was mentioned to add a 4mm cable into the back of the sockets.

Today I was converting some single sockets to doubles, one of the switches had a spur done at some point in the past, I believe to the boiler in the garage which is below the bedroom.

Anyway, the old 2.5mm twisted wire was a nightmare to get into the sockets with the spur.

The neutrals for some reason were more difficult on both sockets for some reason.

I couldn't imagine trying to squeeze a 4mm cable in the back aswell.

The old sockets removed were relatively easy to wire in, even with the spur.

I've added a photo of old and new sockets.

 

[conny]

If you had enough length you may have found it easier to trim the old bare wire ends off, recut the insulation, and then reconnect both sets.

 

[sparkwright]

Do you mean twisted or stranded?

 

[sparkwright]

If the wires (stranded or solid) are actually twisted together, it can help to untwist them, re-strip if necessary, and place in the terminals individually.

 

[sxturbo]

Do you mean twisted or stranded?

Stranded, sorry,

 

[sxturbo]

If the wires (stranded or solid) are actually twisted together, it can help to untwist them, re-strip if necessary, and place in the terminals individually.

All individual, the stranded cable I twisted to make it "thinner" to enable fitment. Was a pain in the bum still though.

New sockets are designed for the solid core and thus the terminals are marginally smaller, but small enough to make a difference.

Point of the post is that when someone suggests putting 4mm cable plus the 2x cables of the ring circuit they just won't fit in a lot of modern sockets.

In my possession of modern sockets is lap, click, and bg and they are all the same, I'm slowly as I decorate each room changing all sockets to click sockets, except for 1 which is a bg usb socket. I have the lap socket as my "decorating" socket so I can have power and continue to paint with the socket just off the wall.

Obviously I can't talk for everything that's on the market, is their sockets out there that still have large terminals?

 

[flameport]

the stranded cable I twisted to make it "thinner"

Twisting stranded wires increases the diameter and reduces the length.

 

[sparkwright]

It can be a struggle getting multiple stranded wires in modern terminals.

Twisting stranded individual wires will increase the diameter as F says, but it may just solid the wire up enough and give a bit of strength to go it nicely, if room to do so.

 

[JohnW2]

Twisting stranded wires increases the diameter and reduces the length.

So does twisting solid ones (in fact, probably more dramatically)

Kind Regards, John

 

[sxturbo]

So does twisting solid ones (in fact, probably more dramatically)

Kind Regards, John

I never twist the cables together, I find the wires look messy and it's more awkward to fit them

 

[JohnW2]

I never twist the cables together, I find the wires look messy and it's more awkward to fit them

That's good, since it can also damage the conductors!

Kind Regards, John

 

[ericmark]

I seem to remember years ago we used 2.9 mm² instead of 2.5 mm² size was reduced when we went metric, also Ian Smith caused a lack of copper at one point and we got aluminium cable for a time, the MK sockets claimed to have larger terminal holes. Cable sizes were given as 7/0.036 rather than 2.9 mm² and it was the diameter of cable not cross section area.

I remember finding in dad's house where socket feed socket etc, the 2.9 mm² into socket looked fine, but the 2.5 mm² to next socket seemed to have melted slightly so it did seem the old cable could take 30 amp where the new cable could not, although since fuse wire never sure it was 30 amp.

Although seen where ring fed lollipop fashion, to take power from the ring at centre using 4 mm² would be OK, but near the source it could cause an overload, so one would need to use an impedance meter to work out how close to centre of ring, in the same way as a double socket unfused spur is allowed but two single sockets are not, even when clearly same load, I would say taking a 4 mm² from a ring as a radial is also a bad idea, as in domestic it is rare to have a plan showing order of sockets, so it is guess work as to how close to centre unless loop impedance meter is used, and these are rather expensive and it is unlikely many DIY people have one.

In the main we use the appendix 15 plan (BS 7671:2008 regulation 433.1) to see what is permitted, and the lollipop is not show, nor is taking a supply from it with 4 mm² the regulation says

433.1.5 Accessories to BS 1363 may be supplied through a ring final circuit. With or without unfused spurs, protected by a 30 A or 32 A protective device complying with BS 88-2.2. BS 88-6. BS 1361. BS 3036, BS EN 60898, BS EN 60947-2 or BS EN 61009-1 (RCBO). The circuit shall be wired with copper conductors having line
and neutral conductors with a minimum cross-sectional area of 2.5 mm² except for two-core mineral insulated cables complying with BS EN 60702-1, for which the minimum cross-sectional area is 1.5 mm². Such circuits are deemed to meet the requirements of Regulation 433.1.1 if the current-carrying, capacity (Iz) of the cable is not less than 20 A and if. under the intended conditions of use, the load current in any part of the circuit is unlikely to exceed for long periods the current-carrying capacity (Iz) of the cable.

I see no problem with supplying a ring final with lollipop method, using a cooker connection unit for example, but not taking a supply from the ring final as you can't ensure power sharing on the two legs of the ring.

 

[crystal ball]

Ian Smith?

 

[wundaboy]

Obviously I can't talk for everything that's on the market, is their sockets out there that still have large terminals?

Hager is pretty good in that respect. The one I've had problems with in this sort of situation is Crabtree.

 

[EddieM]

Ian Smith?

Zimbabwe, maybe?