Rationalizing two boards into one

[Dave Jenkins]

Hi
I've agreed to do a job for a mate. He needs a consumer unit moving from one side of a garage side door to the other (door connects to the house). At the same time, he wants to combine a second CCU with the wiring from the first one.
Modern-ish house and no load issues so combining the two should be OK. I've already done the EICR and it all looks good.
However, the first board has all of the wiring emerging from the rear so I'll need to extend all the cables 1.5, and 2.5 only. 6mm circuit is on the other board.
What is the best way to extend all the cables - crimp/heatshrink sleeving (my preferred method), various junction boxes (won't be enough room to JB everything) or perhaps a combination?

 

[Midwest]

First question is why have two CU's?

Extending cables can be resolved in a number of ways. Bespoke connectors inside new CU, if its just a few. Rewire short circuit legs. Use joint boxes above ceiling void, again if its only a couple of circuits (may need to be MF). Or use an enclosure with a din rail inside with connectors to extend circuits to new CU.

Edit; just re read your post, your are combining the two, say excuse my first line

 

[Dave Jenkins]

My fault....there are two existing CCUs. He wants them combining to make room for other stuff in his garage - I think it's a 'man-cave' he's creating, although thought it best not to ask....

 

[Midwest]

Connexbox do this plastic enclosure with din rail connectors;

New DRE-5 v2 DIN Rail Enclosure - https://www.connexbox.com/shop/wagobox-and-din-rail-enclosures/dre-5-din-rail-enclosure.html
for use with their 'Topjob' connectors. Last time I priced it mind, the enclosure with connectors for standard size fuse board, was pretty much the price of a new CU.

Edit; you could just use a standard metal enclosure, with your vanilla flavoured din connectors from your local wholesalers. I've got one milling around in my garage, with loads of din rail connectors