Back to back consumer units

[herman]

Hi I have come across an unusual situation but my brain is not working..... (I am an electrician btw)

I am putting in a second consumer unit (garage) and it just so happens million to one that the new (second) consumer unit is going on the wall that is 100% perfectly directly the other side of the main CU. In other words they line up - just a double skin wall in between.

As long as I seal the hole for fire can I just not go through one of the back cut outs of one CU and straight into the back of the new one. 16mm singles 10mm CPC. 20 / 25 mm conduit. Fire proof foam / mastic etc.... job done.

That way I don't have to muck with going out of the first in conduit and through the wall and back into the second in conduit.

It looks fine to me but a little voice is saying can't do that......

 

[Rockingit]

I can't instantly think of any technical reason why not - use galv conduit and a bush each end and you don't even have a fire compartment breach. You wouldn't think twice about pushing through a brick wall to back-back an external socket, say, and this is materially no different.