extending a sub main

[tbs1983]

hi guys, I have a job in a flat where a wall is being removed to make it open plan, the wall contains a 10mm T&E sub main that feeds the DB for the flat.
In order to re-route the sub main, I will have to extend it very slightly (2m max), I'm unable to run a whole new sub main due to routes/logistics just not possible.

What is the best way to extend the cable bearing in mind it may be carrying 50A or more.
I have seen large coffin junction boxes but am not overly keen on the idea of using a JB for this purpose bearing in mind the load it may have to carry.
Any better suggestions? thanks in advance

 

[Guitarist]

I thought that under the floorboards was deemed as not accessible??

GLENNSPARK your post 16 says "if...and i say if you are going to joint the cable under the floorboard then at least create a proper access hatch for it...
and make its wereabouts known on the dis-board schedule..."

This is still classed as not accessible, isnt it? I thought that all connections done under floorboards had to be maintenance free. Or have I just read the post wrong ... again...

If there was a proper hatch which was documented, then a joint can be made without being MF. Unfortunately, in the real world, it would likely end up with laminate over the top at some stage, and the paperwork lost.
Due to the other issues the op has, swa is really the only option in this case anyway.

 

[Spoon]

If there was a proper hatch which was documented, then a joint can be made without being MF. Unfortunately, in the real world, it would likely end up with laminate over the top at some stage, and the paperwork lost.

Thanks Guitarist, I always like to learn new things.

 

[telectrix]

a possible way round the problem might be to move the sub-main closer to the main DB without altering it's feed cable - lose a bit of slack in the void. then it could be argued that the feed to the sub had not been altered and so could stay as is. then extend the sub-main circuits to the sub -main, making sure that the alterations complied with current regs.

 

[GLENNSPARK]

Thanks Guitarist, I always like to learn new things.

read #2..

then you learn new things...

 

[D Skelton]

If SWA really wasn't an option then I would be through crimping and feeding up through wall in 25mm galv conduit. It's the only way short of the better option of re-feeding with armoured cable.

 

[Spoon]

read #2..

then you learn new things...

Thanks Glenn. I did read you post 2 and agree with it. No arguments there.
Where I have learned something is that I was under the assumption that anything under the floorboards was classes as 'not accessible' (even if it had an access hatch) and needed MF connections.

 

[Octopus]

thanks for replies guys, joint would be under a floorboard therefore deemed accessible, sub main will be RCD protected. just looking for advice on the best possible way i can carry out this joint as new sub is out of the question (we have explored the idea thouroughly!!!)

Thats inaccessible unless you are going to mark the floor.

 

[UNG]

Have to agree with Guitarist once the laminate floor goes down then it's inaccessible even if the occupier isn't fitting laminate floor now once a year or two passes it may happen

As an aside why is it customers expect you to do the impossible and install or repair something without disturbing the laminate floor or even worse the ceramic tiled bathroom floor