How do I wire a double socket?

Hi all
I have searched on the site and I cannot find the answer to such a basic question.
I am going to put a ring main into my garage and then get an electrician to check out my work and connect to the consumer unit. My problem is that the double sockets I have bought do not have the same number of connectors as the existing sockets in the house.
The double sockets are in the Screwfix metal clad range. Looking at the back of the double socket the connectors are as follows: -
Earth/Live on the left hand side Neutral/Earth on the right Earth on the backing plate?
"Earth/Live on the left hand side" I assume this is the incoming earth and both live cables?
"Neutral/Earth on the right" I assume this is both neutral cables and the outgoing earth?
"Earth on the backing plate?" What goes here?
Thanks, in advance, for your assistance.
Cheers Neil
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Hi Neil,
This page should talk you through things :
http://www.diydata.com/planning/ring_main/ring_main.htm
If you're using metal clad boxes and front plates, then you will need some green/yellow 2.5 mm insulated cable and some green/yellow over sleeve to slip over the bare copper cores in the PVC's. The 2.5 mm green/yellow cable lets you connect to the socket plate from the back box. This makes the installation of the boxes and sockets a little easier for you to do.
After you've fixed your boxes and run the cables between them, you can then wrap the two bare copper cores together and slip some green/yellow sleeve on to them and insert both into the earthing terminal of the back box (don't tighten them up yet). Next you'll need to cut a length of the 2.5 mm green/yellow cable so you can connect from the back box to the socket plate itself. This method of connecting them all together makes sure that even if you have to remove a socket plate, you'll always have an earth connecting core to keep you a bit safer.
I would also recommend that if you're using any tools in the garage, make sure you've connected them into and RCD device, just to make sure that if a fault occurs in the flex or on the body of the tool, you'll have a local point to break the circuit as quickly as possible.
Good luck with it and take your time. Please don't take any chances with electricity.
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Hi Big Wallop
Thank you for replying. Sorry, but I still have my concern about the two earth connectors on the face plate.

Yes, happy with this.

Yes, happy with this.

This is what I don't understand. I have TWO earth connectors on the face plate, let's call them left and right. Do I need to run a length of the 2.5 mm green/yellow cable from the back box to the left earth on the socket plate and then run another length of the 2.5 mm green/yellow cable from the back box to the right earth on the socket plate?

Thanks, I searched on Screwfix.com and saw this IP66 RCD DP 2X13A SKT+ 40A 30MA http://www.screwfix.com/app/sfd/cat/pro.jsp?tsI189&id 090 Is this what I want?

Thanks again for your advice and don't worry, I won't take any chances.
Cheers Neil
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you
If you are using metalclad sockets they should be earthed to the back box. You can use 1.5mm cable and it should be earth sleeved. There will be a ready supply of this cable using the earth cable of the 2.5 T&E cable the ring main is laid in. You can put all three earth wires into one earth terminal if it is convenient.
Adam
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These twin earth terminals needn't concern you in a garage installation - use either or both, whichever is more convenient. Personally, I'd use one for the feed cables, and the other for the link to the backing box.
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Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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Yes. The two earth terminals are provided so that you may comply with the high integrity earthing requirements. This requires the earth loop in a ring main to never use the same terminals at the sockets or consumer unit. This means that if an earthing terminal comes free, the earth loop is never broken. It is a good idea to do it for all circuits when initially wiring. It is much harder to achieve for radial circuits and spurs, as you always need two routes back to the consumer unit, which is particularly difficult if the radial is wired as a heavily branched tree. With a spur, you need to run the main cable, and an additional separate earth cable to a suitable point. I wouldn't bother in this case.
Christian.
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