Help!!!! My tt system mains question!

[819_dan]

Hi all, having major problems with the mains on a TT system. Customer requested new position for CU and to get supply moved by electricity supplier. Now customer won't pay for it after getting a quote from them. The new CU position is approx 6 mtrs away from meter and i'm wondering what the best/safest way to do it is? Did my 17th regs recently but can't find an answer in the big red book. The 1st 2 mtrs the cables can be sitting on joists but the next 4 are in joists and i'm a bit duboius about running d/ins tails through them. Might be o.k but i need to be 100%.
Thanks in advance,
Dan

 

[marcusone]

Hi Dan

You'll need to make this a sub main as it is 6mtrs. You'll need an RCD and isolator on the tails ( 100amp 100mA type s ) if you are using double insulated tails.
Or you can use SWA and use a fused isolator.
On top of joists is not good but have seen plenty running through joists as long as the correct depths and diameters of hole are achievable.

Mark

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This is my understanding but I'm happy to be educated.

 

[819_dan]

Thanks marcus, that's helped. The" on top of joists bit" refers to a void where no boards are going to be laid on top, thought that would be better for heat dissipation rather than going through them?
Thanks again.