Cable routing in new Consumer Unit

[jgp21]

Hi,

I'm replacing an old CU and have a cable length issue. The incoming circuits to the current board have the live terminals entering the bottom of the old MCBs. Most boards have top entry for supply side, and the lives will not reach (Neutral and earth is no problem) if routing in a bundle to the side of the DIN rail.

I could use crimps inside the CU, but that is something I'd want to avoid if possible. There is no space for a connector strip, or JBs outside the CU, as the wiring comes through the wall only an inch or so from the CU.

My question is: is there any reason why I shouldn't route the lives behind the din-rail, as there is plenty of space to do so (and then they will reach the top of the MCB easily enough), or must they be bunched to one side when using a bottom-entry point on the CU.

Thanks

 

[PrenticeBoyofDerry]

You can install to the cables from bottom, side, top or from the back.
Providing the sheath of cable enters the enclosure by at least 10mm, no stress on conductors and the IP ratings of entry points are compliant.
Is there a problem reposition your unit and going in from the back?

 

[jgp21]

Afraid so - the cables come through the underside of an alcove, so it's bottom entry or nothing. . . any lower, and the board would overhand the alcove.

The entry would be fine - the CU is rated for bottom entry, and sheathing is well inside - it's the insulated live core that would pass behind the DIN Neutrals and Earth cores would take the normal route around the side.

 

[PrenticeBoyofDerry]

Providing your phase tail conductor is insulated and sheathed there should be no problems. I assume this is a new CU not an old replacement?
And even though the MI states suitable for bottom entry, the entry knock outs still needs to be compliant to IP2X.
If you can upload and post some pictures of what you have and cable positions, there maybe alternatives or better advise to be offered.

 

[jgp21]

Yep - brand new twin RCD BG Electric CU. Entries should certainly be IP2 compliant.


First image the existing setup . . .not ideal. . .
Second two are the new board. BusBar goes to the bottom of the MCBs, supply side is to the top. As you can see - loads of room to the sides and behind dim rail.

View media item 50355 View media item 50358 View media item 50357

 

[securespark]

Is that a 2.5 on the 32A breaker on the far right?

What does this feed?

Who installed it like that?

It's a fairly new install on harmonised cable...

 

[jgp21]

It is a 2.5, feeding some underfloor heating. I've disconnected since this picture was taken . . . Think it was wired to a 32, as no available 16. Another reason why the board is being replaced. Can't get replacement MCBs.

Any view on passing the insulated core behind the DIM - basically in a straight line from the entrance point to the CU?

 

[EFLImpudence]

Any view on passing the insulated core behind the DIM - basically in a straight line from the entrance point to the CU?

It's better than lots of crimps.

Why do you think it unacceptable?

 

[Iggifer]

could of course replace with another Square D / Schneider board

 

[jgp21]

Just not seen it done that way before and wanted to be sure

 

[PrenticeBoyofDerry]

No problems with runnig the cables behind the din rail!
Gets done a lot!

 

[333rocky333]

it's the insulated live core that would pass behind the DIN Neutrals and Earth cores would take the normal route around the side.

May be neater to take all 3 cores up behind the dinrail, thats one of the reasons it is spaced off the back plate.

Ensure the bare earths are well sleeved so as too prevent accidental contact with any exposed liveparts [busbar] though

 

[333rocky333]

. Another reason why the board is being replaced. Can't get replacement MCBs.

QOE mcbs are proberly easier to get than those new BG ones

 

[jgp21]

Thanks all!

 

[RF Lighting]

. Another reason why the board is being replaced. Can't get replacement MCBs.

QOE mcbs are proberly easier to get than those new BG ones

http://www.screwfix.com/c/electrical-lighting/bg-mcbs/cat1230020

Also at most B&Qs open till 8pm!

I bet they're about 90% cheaper than QOE breakers too!