my my what a long tail you have grandma

[shocked]

Hi all
Went to a block of flats (new) to look at a job and just looked at the meter cupboard (as you do ) the top flat tails must be 8/10 m in length with no isolator just into main credit meter. 25mm on 100A supply.
My question is is there a max length for a run of tails ??
thanks john

 

[Spazz]

Cant see anything in regs at all.
I take that they are installed in walls more than 50mm from surface or ontop of the surface of the wall. therefore not requiring a RCD.
In regards to the isolator again noting in regs.

 

[telectrix]

the tails from the DNO fuse to the meter don't concern you . it's a DNO/Supplier issue, if any.

 

[Mr.Ian]

Isn't there a 3mtr max from meter to C/U without isolator? as from cut out to meter it's DNO isn't it?

 

[Spazz]

Either way its down to the DNO any questions should be put to them.
We are only guessing plus if something went wrong their head is on the block not yours

 

[telectrix]

yep.tails from meter to CU are your responsibility and if over 3m should be fused down to protect the DNO fuse in case mr. numpty nails the tails.

 

[Spazz]

but aint it down to the DNO to put an isolator in as we cant do that safely - not counting removing the fuse!

 

[telectrix]

what DNO should do and what DNO do do does not generally have any more relationship than a meerkat to an insurance broker.

 

[Spazz]

Just thinking as most of us may come across this situation - if we call the DNO do they have to put an isolator in (even if we supply it) free of charge as they are the only ones who can do this?

Ofcourse we can remove and replace the main fuse but the DNO dont like us doing this

 

[GLENNSPARK]

i was talking to a meter guy the early last week....and he noticed the seals were gone on the service head.....then we got talking about working safely....now, he said if you NEED to...pull the bullit....if they see theres been recent work done (C/U change etc)...they will just replace the seal on the next visit....however, if theres no evidence of recent work having been carried out.....he said this could spark an investigation......then he had to go as he had a call through about power pinchers....third time that morning....i could hear em going on about how the police were on their way on the other end of the phone....

 

[oldtimer]

Said it before why not let the spark apply for a coded plastic seal and tell the DNO when the CU change will be changed the DNO posts it out just before the install date job done plus DNO are aware of it plus you can only replace the seal on the main fuse ie not the meter so they will not worry .

What a great idea only thing is the schemies get involved and it all turns to .........................

 

[shocked]

Hi all
Thanks for the replies but still unsure if there is a max length or not ?
these tails were from the supply meter on the ground floor to the various flats c/u no iso just tailed from meter to c/u. dont know how they were installed
bye the way i can guess what DNO is but what does it stand for
Thanks john

 

[Silly Sausage]

See post 6.

DNO... National Grid: Distribution Network Operator (DNO) Companies

 

[shocked]

Thanks A S
read post 6 , but is that a reg
John

 

[Richard Burns]

If you read 433.2, 433.3, 434.2 and 434.3 these specify the positioning/omission of fault and overload protection devices.

If we are installing items then we need to comply with the "no longer than 3m without fusing down" requirement, although there are a few situations where this may not be required.

As you can see from the regs if the distributor agrees that their fuse provides suitable protection from the origin of the installation then they can be a length agreed with the DNO (which is up to them) but the cables must be protected so that they are not at high risk of causing problems.

In general if they are there already and you are not changing anything to do with them leave them, if you need to change anything then fuse it down if over 3m.