Moving Consumer unit, extending ring circuits

[Coatesie74]

I need to move the house consumer unit into the electrics cubby (big white box in house wall) luckily (I thought) toward the feed cable, which requires me to extend the lights and mains circuits. I have a bunch of screw terminal through connectors to extend each Tw/E cable that's currently presented at the old CU but I want to sink the din rail, with all the screw terminations on, into the wall where the old CU is.
The arrangement fits lovely in two double pattresses side by side, however, the terminal blocks are such that the container would need to be 70mm deep.
I assume I will have to leave some kind of removable cover on the surface, be that a door or a blanking plate, for maintenance (that's as much a question as a statement!)
I have searched and cannot find a suitable product. There are plenty of wall mounted boxes but not ones to chop into a wall. Does anyone know of a suitable product?

 

[securespark]

The DNO will not take kindly to your consumer unit being re-sited in their cabinet, which is intended for their equipment only.

If you must, you will need another cabinet for your equipment.

But external consumer units are not a good idea as they are open to tampering and to my mind, not suitable for that location.

Is there nowhere suitable inside?

 

[Coatesie74]

Yes, the cabinet is on the outside wall but inside the conservatory, with nothing in it as the DNO meter etc. is in the garage and the house is a fed from the DB out there. (I know, never seen anything like it before). So all cables and kit are well after any external jurisdiction. It was more about an adaptable box for installing into a wall for the screw terms on the DIN rail as having them in a surface mounted box would result in the same (Head-banging) problem as having the CU there.

Or, do I need to make the terminations accessible at all? does that change if I use Through Terminals or if I crimp and sheath the connections?

 

[bhm1712]

Sounds a bit Heath Robinson - the junction boxes and terminations will need to be maintenance free if buried in the wall and it sounds like you want to use normal terminal (din rail mounted) blocks in a normal electrical junction box.

 

[Coatesie74]

Thanks fella,
Quite the opposite of Heath Robinson I'm trying to keep the task as simple as possible. What would be the maintenance free solution you refer to, I would love to bury the connections in the wall then plaster over the lot. I didn't think I'd be allowed?

 

[OwainDIYer]

You can get CUs which flush fit into a wall. There will still be a slight protrusion for the lid though.

 

[JohnD]

You will have to cut out enough of a leaf of bricks though to make a big enough hole. It is not too difficult in a cavity wall of lightweight blocks, but will cause cold and condensation.

 

[bhm1712]

Thanks fella,
Quite the opposite of Heath Robinson I'm trying to keep the task as simple as possible. What would be the maintenance free solution you refer to, I would love to bury the connections in the wall then plaster over the lot. I didn't think I'd be allowed?

Sorry, as I understood it, you were already planning to bury them in the wall. If not then surface mount boxes with Din rail terminals will be ok.

If you did want to bury them in the wall it's perfectly acceptable if you use "maintenance free" junction boxes.



http://www.superlecdirect.com/p-j80...junction-box?gclid=CP-N4oj0qcwCFUmeGwod2ZUCUg

 

[bernardgreen]

I would love to bury the connections in the wall then plaster over the lot.

If you did want to bury them in the wall it's perfectly acceptable if you use "maintenance free" junction boxes.

How would you ensure that wet plaster did not get into the junction box if the box when buryng the box in plaster. While it may dry out and become non conductive it could reamin in contact with terminals. If at some later date the wall became damp then a conductive path from live terminals to the surface of the wall could be created through the damp plaster.

 

[bhm1712]

Very unlikely but not impossible I agree. However, how else are we supposed to join cables for example if a cable has been drilled through and it's not practical to replace the entire cable?

If installed correctly and the cables are the correct size for the entry and grip then it would be very difficult to get the plaster to go inside the box and make its way into the centre where the terminations are.

 

[Coatesie74]

Thanks, I like the look of those jointing boxes. However, that has only created more questions. (sorry)
There are 2 mains rings and 2 lighting circuits, 6 Tw/E cables. The lighting circuits are straight-forward enough, but, would it be acceptable to have the feed and return from each ring main to go through a single Joint if I had two extender cables coming out to the new CU, as below;

or does that contravene regulations by creating a pinch point and some potential problems with earth currents or some such?

 

[Coatesie74]

The physical installation issues will sort themselves out depending on what solution is employed, I will be putting the joints in the recess left by the old,old fuse board and wiring and could pile the joint boxes in the hole and plasterboard and plaster over them. How would you mark the place where they are, or would you not bother as the connections are maintenance free?
I could sink an adaptable box into the wall and make the connections in there(see original post) I was looking for a steer on a jointing box (as per 'bhm1712') or an adaptable box big enough to house the connections but small enough to sink into the wall.

 

[securespark]

There has to be a safe zone, created by the cables being in line with an electrical box, either horizontally or vertically.

Extend the ring final tails with a junction box for each one.

 

[ban-all-sheds]

would it be acceptable to have the feed and return from each ring main to go through a single Joint if I had two extender cables coming out to the new CU, as below;View attachment 97924

Why use 2 cables for the extension? //www.diynot.com/diy/search/5250483/?q=lollipop&o=date&c[node]=8

or does that contravene regulations by creating a pinch point and some potential problems with earth currents or some such?

I have to say that those notions do not betoken anywhere near enough basic knowledge for you to be doing this work.

How would you mark the place where they are, or would you not bother as the connections are maintenance free?

Maintenance free or not, somehow it doesn't seem right to have joints buried like that. As bhm said, sometimes there is no choice, but here there is, unless you are unable to accept any visible sign of there being something there, e.g. a removable panel painted the same as the walls.

Whatever you do, you must take account of the rules for concealed cables - even a visible access panel does not create a zone for concealed cables.

Lastly, all the extended circuits will requiretesting (info a little out of date, but still mostly good).

 

[Coatesie74]

I assume I will have to leave some kind of removable cover on the surface, be that a door or a blanking plate, for maintenance

That's where I was going with this. I want the finished solution to be either accessible blanking plate or at least have a visual clue by way of a access door. the cables pop out of the wall to go to the CU at the moment and then chase down the corner to disappear into the (currently empty) electricity cabinet, so creating a safe zone/danger zone by using specifically a blanking plate(accessory, installation is not necessary.

"Sheds",

The extender tails will run for about 2m-2.5m as described above, I can't make the lollipop search link work but are you suggesting that I use only 1 tail from each closed ring to the CU?-? (I'm inferring from the term lollipop)

And you might be right, I may lack a little knowledge but then I'm not 17th edition qualified. There is a difference between what will work and what will be considered to be an acceptable installation. I certainly have the skills though, and the information and knowledge is gained through such conversations as these.