Correct isolation for sub main circuits

[jjnr78]

Now, go easy its been a long tough month and I may be over-engineering my thoughts on this:

I was looking at an installation today which has the following arrangement:
main 3 phase service head in 1 location (assume TNS)
25sqmm 4 core swa to a 3 phase DB which then has single phase 63A cbs for 3 submain circuits (16sqmm 3-core swa) to 3 individual consumer units (for 3 shops)
Should the isolation at the DB be double pole rather than single for each consumer unit?

Thanks

 

[gaz76]

cant see any reason why it would need to be double pole, have always used the method you have explained

 

[jjnr78]

I think I'm over-thinking the double pole issue for 'maintenance purposes', but just wanted to be absolutely sure. there are lots of non compliant issues with the work, so it has me questionning everything about the last contractor's design and install techniques!

 

[gaz76]

I see where your coming from on the maintenance purposes but am pretty sure the area in the regs regarding that is for moving parts machinery.