Joining cables

[MarkSmith]

Hi all,

As part of my cellar conversion, my consumer unit is being moved about 2m along a wall. This means extending a number of cables. (Some can be taken back to their nearest port-of-call, but several cannot without much hassle.)

Wall will be plaster-boarded (currently it's mostly brick).

Junction boxes must be accessible, I believe.

My proposal is to put an access panel in the wall roughly where the old consumer unit was...
http://beta.screwfix.com/p/access-panel-250-x-200mm/20924
...and behind that have the required junctions.

Question is: how to make the junctions.

About 10 cables (mostly 2.5mm twin&earth) need to be joined and the 30A JBs needed are much too large to fit 10 of behind a panel like that.

Can anyone recommend a more compact way of doing it? Terminal blocks would fit, but would that be OK, just covered by the access panel?

Thanks!
-Mark

 

[JohnD]

ratchet crimps + heat-shrink sleeving

cut the cables to different lengths so the crimps are not all together, or it will be very bulky.

You must get a proper ratchet crimper, and practice on scrap cable so you can get a faultless joint.

You should not hide cables behind plasterboard as they are prone to damage from drills or nails when a picture or shelf is being put up. If it is in a cellar mini-trunking will be suitable, on the surface of the wall.

The access panel is not such a good idea because one day someone will decorate over it, or put up a bookshelf, and it will never be seen again.

 

[MarkSmith]

Ah, good idea, thanks. Do these need to be accessible like JBs, or can they be hidden behind the plasterboard?

 

[JohnD]

They are a permanent joint so do not need to be accessible for maintenance, but cables should not be hidden behind plasterboard (see above)

It is permissible if they are at least 50mm below the surface but in a cellar surface-mounting is acceptable as well as preferable.

 

[OwainDIYer]

DIN rail terminals in a DIN rail enclosure, shown here adjacent to a CU.

(from Andrew Gabriel on uk.d-i-y newsgroup)

 

[RF Lighting]

I'm not sure I like the ring-radial hybrid circuits there but DIN rail is certainly the best way to move a CU IMO.

 

[ricicle]

I'm not sure I like the ring-radial hybrid circuits there but DIN rail is certainly the best way to move a CU IMO.

Nothing wrong with it electrically, but makes the testing of ring finals only possible from the din-rail box. Makes the form filling a bit awkward.

 

[ban-all-sheds]

As part of my cellar conversion, my consumer unit is being moved about 2m along a wall.

Why doesn't the person you've got to move the CU know how to do his job properly?

 

[MarkSmith]

Thanks all for the replies.

The cellar is being converted into proper living space, like the rest of the house, so it needs to look decent, like the rest of the house. The reason for moving the CU is because when the cellar is converted, the current CU location will be in the middle of a wall. (It already is, but it's a cellar wall so that's fine.)

The DIN rain enclosure looks good but would be almost as big as the CU - so might as well leave the CU there.

Trunking is unfortunately also not ideal - you wouldn't want that up your living room wall.

Why doesn't the person you've got to move the CU know how to do his job properly?

He might do, and he might turn up on the day, and come up with exactly the right solution to give me the neatest possible job without rewiring the house.

Or he might come up with a solution which works and is safe but isn't as neat as I'd like it, and I'm left with a kludge which ruins the look of the cellar conversion. Then a week later I find out about a better way of doing it and have to pay for it all again - possibly involving ripping up nice new walls.

Worth having a bit of an idea before he turns up, I think. Many heads are better than one.

I'm surprised about cables having to be 50mm behind the wall. I can understand it entirely but the entire house has cables under the plaster. Primarily below sockets and above switches but also elsewhere.

 

[ban-all-sheds]

The cellar is being converted into proper living space, like the rest of the house, so it needs to look decent, like the rest of the house.

Could you put up with something like this on the wall?

Or build a cupboard around it?

Trunking is unfortunately also not ideal - you wouldn't want that up your living room wall.

Whatever is done will have to comply with the regulations for concealing cables.

He might do, and he might turn up on the day, and come up with exactly the right solution to give me the neatest possible job without rewiring the house.

Or he might come up with a solution which works and is safe but isn't as neat as I'd like it, and I'm left with a kludge which ruins the look of the cellar conversion.

Then tell him what your requirements are and ask him to describe/demonstrate his solution.

I'm surprised about cables having to be 50mm behind the wall. I can understand it entirely but the entire house has cables under the plaster. Primarily below sockets and above switches but also elsewhere.

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
  
  
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
  
  
• IEE article
  
  
• IEE Article on 17th Edition requirements for concealed cables.

 

[MarkSmith]

Could you put up with something like this on the wall?

Is that a semi-recessed CU? That would be possible, although it'd only be a few cm shallower than a normal CU unless I hack out brick. Also the cables would still run up the wall to it, behind the plasterboard. Would that be acceptable as it's running to the device, or is it still a no-no?

Or build a cupboard around it?

What's the "it"? The CU? It's not really too ugly - just sticks out a bit.

The original plan was to put (some form of) JBs where the original CU was, and put a shallow cupboard over them. Not ideal, and I thought the access panel option would be preferable (almost flush to the wall, but giving access (if necessary) and marking the area as clearly different from the rest of the wall.

Whatever is done will have to comply with the regulations for concealing cables.

Absolutely. Trying to find something which complies, is safe, and looks good. We're circling in on the right solution, I can feel it

Then tell him what your requirements are and ask him to describe/demonstrate his solution.

Exactly what I did. "Cupboard with JBs" was the answer. That's "just about" OK, but I think we can do better.

Thanks for the links. I do believe you, I'm just surprised as that regulation seems to be blatantly disregarded quite a lot. In my experience, at least.