Ring main extension from redundant spur

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martinw1UK

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Hi,

I would like some advice. I have built a small extension at home for a home office which I would like to put 5 double sockets in just for phone charging and a laptop and printer. Bever more than that on at the same time. To run back to the board is a bit of a pain.

The other side of the wall is the kitchen and the ring main. There is on the ring manin a redundant fused spur that was for an extractor fan we no longer have. I am no talking about using the spur. What I am talking about doing is the ring main comes in and out of the fuse spur switch. So where it comes in to the box can I put some suitable connector blocks (60 amp rated on a 32 amp circuit) go out into the extension and run around in and out of my 5 new sockets then back into the box and connect to the ring main out.  Then close it with a blanking plate. Effectively extending the ring main into my extension.

Firstly is this safe and secondly will it work it would save me a massive amount of work.

 
Unsure from your description if you are intending to just try and stuff 3x four cables (L, N & E of old ring & extended ring) all together into a single 3 terminal 60a connector block?

In which case it would be dangerous and unsafe as you would have created a figure of 8 rather than extending the ring...

As to extend the ring correctly you need to do 1x existing LNE connect to 1x new LNE...  

then second new LNE connected to second existing LNE....

Both sets of LNE must be kept independent of each other.

If you are trying to use 'overkill' 60a terminal blocks..

Then I reckon you could have a bit of a fight getting 4x 2.5mm cables and 2x 3way 60a terminal blocks in a single socket box..

Until you have tested the existing circuit to confirm the fused spur you intend extending off is actually part of a ring...

(measure continuity around each leg L, N & E),  then it could also still be dangerous and unsafe.

I have attended loads of jobs and found ring to be broken somewhere around the circuit...

Which the customer is unaware of, as "it still works"

(Kitchen fitters are notorious for messing up kitchen socket wiring by just extending and spurring off existing accessories..)

If you want to know if it is safe then... 

You also need the ability to verify the continuity of the new extended ring..

And the operation of the RCD..

and/or install an RCD if one not already on the circuit..

And to verify the earth loop impedance is within wiring regs tolerances..

If the load you describe is accurate for your new extension...

It sounds to me a bit daft & overkill to extend the ring in & out..

Probably easier to just leave spur in place and extend your new sockets as a 13A radial off the spur..

i.e.  you could have plugged all those items into a multi outlet extension lead supplied via a 13A plug without too many issues.

:coffee

 
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