Extending Ring Main via 30 amp commecting block?

[marcus]

Hi,

I want to extend the ring main that we have in our dining room to provide extra sockets to the other side of he room. I want to add three extra sockets so I want to extend the ring instead of just adding a spur.

In the past, when I have wanted to extend a ring, I have used a 30amp junction box to do this taking one of the wires from the socket that starts the extension of the ring into the box, run the extension and finsihing in the intial socket to pick up the exiting ring again.

Unfortunately, this time this will be difficult to do as the cables are burried into a solid wall and adding a junction box means that I will have to chisel out the existing cable to add the junction box - thus running the risk of damaging the cable.

My question is: is it acceptable to extend the ring by connecting one of the wires in the exisiting socket to the new wire run using a 30 amp connecting block, running the wire to the new sockets, and back to the existing socket, the far end of the new wire run will connect into the existing socket and then from there the existing run of the ring would continue. I'm not sure if I've made myself clear so to summarise, I want to know if it would be OK to:

1) In the existing socket disconnect one of the two cables from the socket/plug 2) connect that cable to the new wire (witin the confines of the existing socket box) via a 30 amp connecting block 3) run the new wire to the three new sockets 4) come back to that first socket box where the far end of the new wire would be connected into the socket/plug there and then the ring would continue on its original course via the 2nd original wire that was in that socket.

Is this a OK thing to do or do I really need to do this via a junction box?

Sorry for the long message but I found I had a little trouble trying to describe the whole situation!

Thanks in advance for any help

Marcus

[David Hansen]

On 23 Mar 2007 05:23:09 -0700 someone who may be [e-mail] wrote this:-

Yes, provided the workmanship is to an acceptable standard and the continuity of the ring is tested after the alterations.

A few things to note:

1) There is more space to do this in a double box than a single. If you are planning to extend from a single then it can be worthwhile considering converting this to a double.

2) The terminal block can be separated into three terminals to make it easier to get in the box.

3) It is a lot easier to get everything in place with deeper boxes and the shallower type of socket. The old Tenby range was good for this sort of thing, as are the modern single to double or double to triple convertors.

[John Rumm]

yup, this is fine.

I second what David said, and would add:

another way of getting more space in the back box is to use insulated crimps in place of chock block connections.

[marcus]

Hi John,

Thank you to both you and David for your helpful responses.

Just another quick question on your response. I've never used crimps for electrical connections. Would you be able to point me at a web site, book or product that would explain what I need to do this? Is there something I could buy that would have all of the bit & pieces I would need from somewhere like Screwfix etc? Or, given my obvious lack of experience here, would I be better sticking with the block connectors.

I have noticed that you have suggested crimping for other applications such as repairing wires in the past, so I would be interested in learning how to do this.

Thanks again for your help.

Marcus

[The Medway Handyman]

Make sure you buy a good quality ratchet crimper. The non ratchet ones aren't good enough.

[John Rumm]

make a very strong permanent connection. (I usually order mine from CPC - tad cheaper than TLC for these).

[Ian White]

Looking at all the various connectors on that page, exactly where along their sleeves are they *intended* to be crimped? How much difference does a mm or two make, either way? It seems to be one of those things that everybody is supposed to be born knowing.

[John Rumm]

When you look at the connector itself it is a bit more obvious. The first bit of sleeve is just that - sleeve with no metal in it so that you can slide the insulation of the wire into it to provide continuous insulation without risk of a gap. The bulk of the rest of the terminal is not much longer than the width of the business end of the ratchet crimp tools.

[marcus]

Sorry to ask mega obvious questions but....

So in the connector, do I strip a bit of insulation from the wire, insert this into the butt connector "sleeve" up to the insulation on the wire, then crimp? And then do the same at the other end? I know this seems very obvious but I want to make sure that I'm doing this right!

Thanks very much for your help.

Marcus

[Steve Firth]

The metal to metal crimp is made in the centre sectin of the connector. If done properly it should be a cold weld.

I've not used crimps for decades but when I did use them, they were then crimped again (using a different slot in the jaws) to crimp the plastic sheath onto the insulation. This doesn't do much except to provide a limited amount of mechnaical support.

Now it seems that the ratchet crimping tools do the entire job in one operation. I've got a ratchet crimping tool, but haven't used it because the job I got it for is "on hold" for a time.

[marcus]

While I'm at it, another question...

Given that I'm attempting to join two cables that are 2.5mm two core & earth, I presume I should be using blue 2.5mm butt connectors? Is this a correct assumption?

Thanks again for all the help.

Marcus

[Andrew Gabriel]

No. You put both ends in at the same time and crimp once.

Practice on some spare bits of cable first, and try pulling apart.

[Lurch]

On 24 Mar 2007 17:13:16 GMT, [e-mail] (Andrew Gabriel) mused:

No you don't. You do it as he said. Crimps aren't designed for more than one cable per end.

[Andrew Gabriel]

You've misread what I wrote.

[John Rumm]

Yup, strip the insulation from the wire and slide the wire into the terminal until its insulation hits the metal (which will now be a few mm inside the sleeve.

Yup.

[John Rumm]

That does depend a bit on the length of the terminal... the CPC ones I usually use require crimping twice - once at each end. They are also wide enough to just about get 2 x 2.5mm^2 wires in each end at once, so you can leave the ends longer such that the wires fly past each other in the terminal, then one crimp will get both at the same time.

Yup, definitely.

[Lurch]

On 24 Mar 2007 19:18:11 GMT, [e-mail] (Andrew Gabriel) mused:

Ah, see what you mean now. I've never had a butt crimp that can be crimped in one movement, and I've crimped thousands of them!

[8184496]

replying to marcus, 8184496 wrote: That should be fine, provided that you use at least 2.5.sq.mm twin and earth cable, (or 4.0.mm if the old circuit was wired in it), and once the 30amp connector blocks are installed inside the box, you use a standard white blanking plate to cover the former socket / joint box, to tell future owners that there are electrics behind there. DO NOT under any circumstances, try to plaster over or wallpaper over that white blanking plate, as it can cause problems with wires being hidden from future owners.

[tabbypurr]

Does homeownershub really think people want replies regarding what they're about to do 8 years later? Please access this group from a competent interface somewhere else, one that is basically functional. Google groups is free.

[ARW]

2007 was a good year.