Meter Tails 16mm 0r 25mm

[High Tower]

Talking with Tony Cable from the NICEIC the other day at the ELEX show in coventry.

There is talk of a pilot scheme to start where registered Sparks would be given the authority to remove main cut outs for isolation purposes, also in this capacity the sparks would have the facility to re-seal the cut out.

I can only assume that from the suppliers point of veiw, this saves the resources of their area engineers coming to re seal a installation after major works where a certificate has been issued.

In light of this position i can only assume that the sparks will be able to acsess the meter to insert CU tails and also reseal this as such.

As for mater- cut out tails??? well im guessing that it will be within the sparks re-mit to change but it will probably contine to be a gray area.

How do i personally get around this. Well i have previously changed a CU with the tails to the unit live using insulated pliers and a clean pair of boxers.

Would i ever do it this way again???? Not bloody likely!!!!

So i use a pair of these to grip the fuse :

http://www.hyperclaw.com/pic/products/vde_water_pump_L.jpg

I dont grip to hard so i break the carrier but it stops me getting a ****er!

I shield my face as i pull it

The experienced guys probably think its over kill but i have heard to many horror stories, i think the most importaint part is to pull the fuse in one smooth action to avoid arc-ing

 

[Spudnik]

The fuse should not arc at all if the load is isolated.

There are some DNO's that permit registered sparks to pull the cut outs and give seals as a temp until they get round to fitting the correct ones.

Even if the do eventually give permission for us to pull the cut outs, they WILL NOT give us permission to change any tails from the meter.

IMO.

 

[High Tower]

The fuse should not arc at all if the load is isolated.

There are some DNO's that permit registered sparks to pull the cut outs and give seals as a temp until they get round to fitting the correct ones.

Even if the do eventually give permission for us to pull the cut outs, they WILL NOT give us permission to change any tails from the meter.

IMO.

Yeah it shouldnt arc and its probably me being paranoid.

Your opinion as far as what the DNO's will and wont allow is probably better than mine

 

[ronturner]

Can we re-cap.

To replace existing 16mm tails from the meter to the CU.

Break seal and pull the fuse - meter now dead

Break meter seal and replace old tails with new 25mm.

Replace fuse and meter cover plate.

That's two seals cut. Or you could (not so safe) just cut seal at the meter remove old tails and replace.

Point I'm making is that cutting the fuse seal only is not enough if you wan't to replace the tails from the meter to the CU. Another (compromise) is to pull the fuse and then put the exisitng 16mm tails from the meter into a Henley Block and then go out from there with correctly sized 25mm tails - then request the board to remove Henley block and put new tails into the meter at their leisure.

The present state of affairs is a nightmare for practising conscientious electricians. Anyone attempting to ring EDF or similar and hanging on the end of a phone listening to music and then being pused onto another department etc etc will know. It is time that either we as registered qualified Electricians are given the green light to cut seals or the suppliers allocate enough funds to have a team of technicians on stand by to remove and replace seals.

My solution is very simple. Electricians cut whatever seals are required to carry out the required work safely and then they fill in a form which they send to the supplier to inform them that the seals have been cut and require replacing.

 

[ezzzekiel]

this old dog argument is always brought up, but main points to note are:

you should NOT pull a service fuse if a seal is present or not

you should NOT alter any cables at service head no matter what size or condition they are

there is no excuse, if you are caught you can be prosecuted.

Do most people just do it - yes
Do I do it - yes
but everytime its done you must understand that you are breaking the law and if Dno decided to prosecute (which would most likely be under extreme circumstances) then you would lose.

Ive always stated that any partp registered electrician, upon joining a scheme should get as part of there joining fees a PTO cert and set of sealing pliers issued!

 

[Gravid]

I agree with getting a re-sealiing kit when you join a scheme.

I always have a nagging doubt about leaving stuff un-sealed after i've worked. I spotted these a while ago whilst looking for a meter, the flag ferrules or the square lead ones on this site look really similar. Thinking about getting a kit, what do you reckon ? Security seals and pliers

 

[EWebster]

I agree with getting a re-sealiing kit when you join a scheme.

I always have a nagging doubt about leaving stuff un-sealed after i've worked. I spotted these a while ago whilst looking for a meter, the flag ferrules or the square lead ones on this site look really similar. Thinking about getting a kit, what do you reckon ? Security seals and pliers

I think it's safer to crimp after replacing the tails. Stops accidental or deliberate removal of the fuse or meter cover by anyone else, including an overzealous DIYer!

 

[High Tower]

Just a point to mention, when i re-wired my own house, i pulled service fuse and broke seal on meter and put pretty new tails in, Juiced the board and went about my merry way.

I thought i had better show willing and placed a call to the DNO to let them know, especially as the tails were 70yrs old and about 4mm2.

I called them in April 2007, guess what i still havent seen sicht or sound of them.

I wouldnt like to be waiting for them on a job to pull a service fuse

Cheers Eon crap as always

 

[NoSparks]

Don't guidelines say when replacing a consumer unit you have to replace tails as well? And as you're doing that, you need to cut the seal to the meter to install the new 25mm tails.

Id be intrested to know the reference?

 

[flukey]

Id be intrested to know the reference?

me too

 

[EWebster]

Id be intrested to know the reference?

The green book (Guide to Building Regs), is where I saw it as far as I remember. I'll look it up and get back to you, but pretty sure that's where it's from.

 

[m25maintenance]

when d 80 a head was fitted 16mm were ok, but now all tails 25mm unless u are sure the maximum demand of the installation wont exceed that

 

[JPAT]

Check out "Essential Guide" on NIC website. 16mm tails are ok if all conditions are met. Use 25mm tails and you will definitely be ok!

 

[jasew]

I found this on the ESC website on the best practise guide

6. Main earthing and bonding and
meter tails​

6.1. The installer must verify, as a minimum, that:
a) the main earthing terminal of the installation is
connected to an adequate means of earthing
via a suitably sized earthing conductor,
b) the main protective bonding is adequate, and
c) the meter tails and the distributor’s equipment
have adequate current-carrying capacity.​

Note. Some electricity distributors have requirements regarding
the earthing conductor, main bonding conductors and meter
tails that exceed the requirements of BS 7671.​

6.2. If any of conditions 6.1 (a), (b) or (c) is not met, the
customer should be informed that upgrading is​

required.

I'm about to change a consumer unit with 16mm tails, if the main fuse is 60 or 80 A then I should be okay, 16mm = 87 A.

 

[malcolmsanford]

IMO if it's a 60 amp DNO protextion fuse then 16mm^ tails are fine. If it's 80amp or 100amp I would be wanting to fit 25mm^ tails. In all honesty the cost of 25mm^ tails not being that much I would try and fit 25mm^

 

[ezzzekiel]

i can never really understand these types of questions, tails are cables and should be rated the same as any other circuit design if 16mm can carry the required current and the service fuse is correctly rated then whats the problem?

the osg basis all its designs on a 100a supply.

 

[Engineer54]

I think it will be very unlikely that a domestic installation will be drawing more than 60A for any length of time. Getting close to that figure, will only be in situations where instant shower units are in use. Even then, the average time a shower is in use is counted in minutes ...not hours.

Going back more years than i really care to remember, when those that had electric ovens, were going full pelt over the Xmas holidays along with electric heaters of various ratings blasting out heat and head fuses were rarely above 40A (as were the ratings of the DNO meters. The on-call Authority electricians rarely, if ever got called out to replace blown head fuses or burnin/melting tails, ...lol!!!.

Now days, all we want to do is increase and increase fuse ratings and tail sizes.... The chances are that the DNOs supply cable is far smaller in size than the tails, especially if it is an older property!! Not only that, anything that much newer, and of anything like 25mm, will probably be in aluminium conductors too!!!...

 

[Dan]

Just bumping some threads in the Electrical Wiring Theories and Regulations forum category here on our Electricians Forums. If this specific topic isn't current, just ignore it, it'll drop off the list in no time. However, if it's something you'd like to contribute to, feel free to reply and bring it back into current discussion.