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Ring Main Joint Box

PG
A kitchen worktop twin S,O, is to be relocated horizontally by about 60cm. 

The ring final cct (RFC) is cabled in buried T&E and the galv' steel back-box is flushed into the plaster/brick wall.

The RFC T&E extension cabling will be buried under plaster, covered in plastic capping along the horizontal  prescribed zone. Visually, it would be reasonable for an electrician to be aware that the route may contain cable(s).

The circuit is RCD protected.

The intent is touse insulated crimp and double insulating tape the jointed cables within the existing box to achieve a maintenance free connection, A 2mm thick (fabricated) plate was to be used to cover the back box and provide additional mechanical protection. The box would then be plastered over.


The questions are:-

1. How many would consider the steel plate back box cover a desirable feature or would a simple plastic cover suffice?

2. Should the original back box be left  unearthed?


Thanks in advance.
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    An accessory, or blanking plate, fitted directly above the hidden box at high level would define a zone below it. Ideally with the plaster cut away to expose the cables, to ensure exact location and avoid screwing into them.

    As for earthing the old box, depends on your method of maintenance-free connection, the screw terminal for earth connection in the box would not be maintenance-free. I might not bother tbh, it would be a random bit of metal behind tiles, unless there is earthed metal conduit in the drop which acts as a cpc.


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    PG:

    Thanks - I have never earthed steel capping and was thinking that it may be as well not to introduce earth potential in the box.




    Rewire - some cable drops in mini-conduit; some under plastic capping; some under steel capping. The last gives one the opportunity to demonstrate to the children the magic walls with mini-magnets. ? The implication of the steel capping is that one needs to be careful, very careful, when pulling in the new cables.


    Capping does not satisfy the requirements of 522.6.204. It does not have to be earthed, but the circuit should have additional protection by RCD. I suggest that a steel back box should be treated in a similar way. No need to earth, but even if it was, it would not be a substitute for additional protection.

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    Bye heck! This is like drawing hens teeth.


    From the new box the cable will run 600 mm horizontally, then it will join the original drop from the ceiling.


    If someone decides to put a shelf up above the sink how will they know where the original drop comes down the wall with the original socket location having been concealed?


    It doesn’t comply with the regulations.


    Andy Betteridge
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    Please see Chris Pearson's advice above
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    Thanks - I think that I may switch to the silicon seal of a blank plate proposal.


    Earthing of the box?


    Regards

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    Yes but if you remove a socket and leave the cables there after it has all been replastered how is anyone going  to know were the original drop is? If you remove the original socket then the existing drop will no longer be in a zone.
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    There will not be any indication where the existing drop to the box that is going to be concealed is.


    Andy Betteridge  

     




    There's the usual line of sockets above the work top. They could be fed from a vertical or horizontal position (as 7.3.2 of OSG) unless I've misunderstood. I don't see a reg' that says you can't swap from vertical to horizontal?

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    In a reception room (public room for the Scots) the sockets would usually be supplied from below, but with solid floors could be from above.


    Kitchens are rather different - the sockets are, more or less, half way up or down. I see absolutely no reason why there should not be a drop, or rise, to one socket and then the cable horizontally to the others.


    So with good reason, the OSG makes the zones up-down, left-right. I agree that if an old socket is buried, the zones might be obscured. Horizontal may be maintained, but vertical will not be.


    ETA: I think that we are all in agreement - I was typing as others were posting.
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    Typiod:

    As Andy has said the drop to the original socket will not be in a zone, so would not comply with the regs.




    As Typoid has said the drop to the original socket will not be in a zone, so would not comply with the regs.


    Andy Betteridge 

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    Sparkingchip:

    What’s wrong with lifting the floor up in the room above the kitchen and moving the cables so they drop straight into the new socket?


     Andy Betteridge 




    Nothing wrong with your alternative. The horizontal link is easier, I can do it before the kitchen fitter removes all the existing units on the wall.

    Do you think that there is something incorrect with the proposed method Andy?

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