meter tails over 10 meters best way to do it

[pablo4321]

Hi just after a bit of advice,we are wiring a new build where the meter is, the tails will be coming from outside into the kitchen they will be coming up the wall to the ceiling along the the middle of the joists to the consumer unit in the wall what is the best way to do this

1) shall i run them in steel conduit and earth the conduit to the earth terminal in the meter.
2) do i need a overcurrent switch fuse in between
3) and is it acceptable to use just normal meter tails to run under the floor in the middle of the joist.


thanks for any advice.

 

[KAS1]

WHO DO YOU THINK YOU ARE >.............................inspirational contributions to the forum continue with limitless technical insight

and havent you heard of zinc plating ?
and ive never seen a roofing bolt rust inside a weatherproof enclosure.

every time you shoot your mouth off i'm gonna be right here to pull your pants down in public.
you just dont learn do you ?

 

[Silly Sausage]

Hahaha...:smilielol5:

 

[KAS1]

There's some bodgers on here, yet they don't even know it, never mind I'll keep pointing it out to any of them..............even if just one put a brass bolt in the better.

 

[Engineer54]

Oh my, unqualified people making comments on a subject unqualified people have no business playing with and people seeming to ignore the regs that require meter tails to be no more than 3m long, after that they become a sub-main and must be wired in an appropriate manner.

Running tails via conduit is a simple none-starter, so your left with SWA and Pyro. Pyro is clearly outside to price range of all but commercial installs these days in special locations so your left with SWA. Meter tails are required to be 25mm² and for the purposes of common sense I would personally and professionally suggest that the sub-main also be 25mm², regardless of the sub-main being fused down to 60A or 80A. There may come a time when they want a larger supply and so this would need to be rewired if in 16mm², not easy in a finished house.

The correct way to do this would be

Head > Meter > DP Isolator > Sub-main > RCD Main switch in CU

That's not strictly correct!! And what of the DNO supply cable becoming undersized in the future?? Professionally you would make an on-site assessment of what's available, what's required and what is reasonably to be expected in the near future.

As for others suggesting using SWA, ...agreed. but remember, if were talking about a new build, then were also probably talking of a PME DNO supply, which means that any SWA being used for the tails, must include a 3rd core earthing conductor. The steel armouring of a 2 core SWA cable, will not have a sufficient CSA to comply with a PME connection...

 

[somersetsparks]

Well, Well, Biff I've snagged more jobs than I care to remember, I'm afraid if my standards are much higher than you are used to, it doesn't make me wrong, YOU HAVE NEVER SEEN a roofing bolt inside an enclosure rust, well well perhaps a visit to specsavers is in order. If I see some of the young lads taking a short cut I'll speak out, so I'm afraid it's time you took note of a few of more experienced members on this forum lol have you never worked on a power station or for the PSA or come to that any major construction site, if you had you would not be using roofing bolts instead of brass I can assure you. (you would not last long)...........

Whilst I agree that a brass bolt is the proper way, roofing bolts are designed for roofs and gutters and as such are suitably rated to withstand the elements, admittedly quality has probably slipped but still a perfectly acceptable method, after all trunking and conduit are made of galv steel are they not?

 

[KAS1]

Is this a serious question lol

thanks rocking it thats looks neat, just another question the bit round the armour where you have earthed it where do you get them from and what they called thanks

 

[KAS1]

Thank God we still make SWA glands out of brass (99% of the time that is) I also use Brass bushes, Brass frying pans lol we could start using galv rod as the norm for earth rods lol

Whilst I agree that a brass bolt is the proper way, roofing bolts are designed for roofs and gutters and as such are suitably rated to withstand the elements, admittedly quality has probably slipped but still a perfectly acceptable method, after all trunking and conduit are made of galv steel are they not?

- - - Updated - - -

Biff ..................take that

 

[driverman]

Out of interest...is that the DNO's OMB? Will they let you install a switchfuse / RCD within the OMB?

 

[Outspoken]

That's not strictly correct!! And what of the DNO supply cable becoming undersized in the future?? Professionally you would make an on-site assessment of what's available, what's required and what is reasonably to be expected in the near future.

As for others suggesting using SWA, ...agreed. but remember, if were talking about a new build, then were also probably talking of a PME DNO supply, which means that any SWA being used for the tails, must include a 3rd core earthing conductor. The steel armouring of a 2 core SWA cable, will not have a sufficient CSA to comply with a PME connection...

Most DNO's insist on 25mm² meter tails, it has been the recommendation in the OSG since at least the last version under the 15th (brown I think) and was a recommendation from 1984 (yellow version of 15th) for all PME service heads. The exception being where the fuse was unable to be uprated to 100A or the terminals were physically too small to accept 25mm², this being a problem on older heads rated at 40A and 60A.

In this situation though we are discussing a sub-main and not standard meter tails and considering, as I said in my earlier post, you have to de-rate the cable to take environment into account

 

[somersetsparks]

Most DNO's insist on 25mm² meter tails, it has been the recommendation in the OSG since at least the last version under the 15th (brown I think) and was a recommendation from 1984 (yellow version of 15th) for all PME service heads. The exception being where the fuse was unable to be uprated to 100A or the terminals were physically too small to accept 25mm², this being a problem on older heads rated at 40A and 60A.

In this situation though we are discussing a sub-main and not standard meter tails and considering, as I said in my earlier post, you have to de-rate the cable to take environment into account

I work for a DNO, and as far as Im aware no DNO insists on 25mm tails but most insist on 16mm earth

 

[somersetsparks]

Out of interest...is that the DNO's OMB? Will they let you install a switchfuse / RCD within the OMB?

Technically not, but most don't mind, in fact most don't give a flying ****, They don't like fuseboards in there though!

 

[driverman]

used to work for a DNO :leaving:

 

[Deleted member 72666]

OK ............ but you'll have to buy me a Jack Daniels - a whole bottle of it - and a spliff first !!! :54::sifone:

Would you 2 love birds pack it in, there's trouble brewing....

 

[tidyboiler]

OK ............ but you'll have to buy me a Jack Daniels - a whole bottle of it - and a spliff first !!! :54::sifone:

Jeez Geordie, you will be having a rainbow tattoo soon, and wearing pink handcuffs!!!!! You've been hanging round too many faggots....... :tongue3:

 

[Outspoken]

I work for a DNO, and as far as Im aware no DNO insists on 25mm tails but most insist on 16mm earth

Can't speak for Somerset area, not sure who the DNO is around there, but in London, Essex, Cambridgeshire, Lincolnshire and the home counties the DNO has always insisted on 25mm², but if they don't elsewhere that is fine, no issues there for me.