can not remember off the top of my head but can remember it well as had an argument over it with local authority and npower backed me up on it. i think it was covered when i did my regs course as someone asked about tails lengths: 434.2.1 BS7671:2008 regulation 433.2.2 says 3m
They are to do with such things as bus bar chambers where the csa of the bus bar changes or when you want to run instrumentation off a very large csa cable carrying a lot of amps, like say, putting a volt meter supplied in .75mm flex on a 25mm supply cable. Some people have also thought they limit the length of say, a fused spur off a ring final. Nowt to do with length of tails.
It's not a BS7671 Regulation. It is a DNO stipulation as to maximum length of tails permitted without customer-owed overcurrent protection. (Different DNOs have different rules.) As it is their supply it is their right to stipulate this.
Nothing to do with cutting it - he wouldn't connect it up in the first place (if that DNO's requirement is for <= 3m - as I said it varies depending on DNO).
So what if the cu was moved and the rec didn't know? Or even if they DID know, what then? Send the Police round?
I knew I read something about this before. So searching my OneNote achieve I found this This an extract from a DCUSA document De-Energisation - Frequently Asked Questions
Loads of B.S. on here I would split tails with a Henley, local cu for garage then SWA switch fuse for main board, will have to calculate for volt drop and as a sub main will not benefit from 5s disconnection as local board will be .4s disconnection but might need a larger cable size depending on final v.d. Get a proper electrician in because there are plently of things to consider. P.S. no you can't use long meter tails for it.
Ok part 5 chapter 52 (except from the meter to the local equipment) It's a bit like saying why can't I use polly pipe for my gas cooker, it would work but it is a substandard of workmanship The regs arn`t law but YOU CAN be prosecuted with them. Why not as its a new build run ALL the circuits into the garage ???
* Its industry recognised by electricians that DNO's stipulate the maximum length of meter tails as they don't want you relying on their fuses when you've created a distribution circuit...Their fuses are only there to protect their equipment...why is that so hard to comprehend?
"SP Networks were OK yesterday with the 6m tails between meter and consumer unit - said I was willing to fit switch fuse due to extended length, told not to worry about it " - My post from September last year on a similar thread. So much of the regulations are open to interpertation why not just phone up your DNO tell them your situation, take their advice and get a good nights sleep
No, I don't think I am. I think I actually have the intelligence to question most things in life when I see things that don't make sense to me based purely on peoples beliefs rather than facts. What industry is this? The IET? BS7671? The Rec? The supplier? Who? If you can't even make your mind up on that then what basis does your argument have? Well where exactly does it say this? Do you have a link? Is it the Law? What happens if a CU is moved without the "industry" being told? Does it get cut off when the meter man goes round? What happens then to their "want"? Ah yes, the magical properties of the suppliers cut out fuse, it only works up to three meters beyond the meter tails and then suddenly stops. Clever that eh? Meh...