Main Earthing Conductor

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w/e. i will be the first person to put my hands up if i am wrong....

why dont u draw us a pic to explain why u think u r right.....

 
chris, dont take this the wrong way but r u a spark or plumber?

Cheers Lee

See, theres no pressure on me im just a plumber:^O

But those Senior Member Sparks:Blushing:

Regards chris

 
I`m here.......

I`ve read through the thread to date; not I`m going to go and read up a bit before I wade in....

However. If this has all come about due to the connection to the undersized EC at the HED, then its nonsense.

Just because you fit a TEMPORARY through connection beside the HED, as you cannot access the earth termainal within the HED, doesn`t make that an MET!

 
if you think getting a 10m cable to a stop tap is hard, try getting 2 x 15mm pipes to a radiator in a fully tiled bathroom or kitchen or 6 pipes out of a cylinder cupboard and down a hall to each room . :) you sparkies dowt know the meaning of difficult lol.....

(awaiting abuse)........!!!!!

see below. :)
X( :yellow card no on second thoughts Wet Fish headbang :red cardbad day explodebad day explode:innocent you forgot this :coat :^O :^O

 
A TNCS earth will usually go to a block with screws... sometimes it comes directly out of the head and then to the CU, if that is the case then I'd probably cut it so that there is only a few inches left and put that in an earth block and then take your 16mm earth from there!
10mm could be acceptable Noz, if Tails are less than 25mm

 
Don't forget though that if you put a new Earth connecting block before the CU then the Earth Block in the CU is no longer the MET...Correct and the new one becomes the MET Correct ....so all bonding needs to go back to that.
Incorrecta1 spark

 
A bit more info on the subject under discussion...extract

3. Main Earthing Terminal (MET) and Building Earth Marshalling Terminals (BEMTs)

An installation has only one MET, even where the installation serves more than one building. This is the terminal or bar connecting the protective conductors of the installation to the means of earthing (see Topics M13-5 and E45-25), and is normally located at the origin of the installation (the position where electrical energy is delivered to the installation).

In a building other than that containing the MET, a Building Earth Marshalling Terminal (BEMT) is often provided, to marshal together the main bonding conductors connecting to extraneous-conductive-parts, if any, and circuit protective conductors (cpcs) at the building.

A BEMT has to be connected to the MET by a cpc and, where there are extraneous-conductive-parts at the building containing the BEMT, by a main bonding conductor. It is often the case in practice that the cpc is also used to perform the function of the main bonding conductor. The requirements for the csa of such a dual-function conductor are discussed in item 4.1.

a1Spark

 
In reference to M4ttys original question, I would say that as the Earthing Conductor terminates in the DNO cut out ,then he should not tamper with it. He can either contact the DNO for advice on a possible upgrade or he can note the size on his Cert.

a1Spark.

 
Incorrecta1 spark
If you can not be bothered to comply with the regs that's one thing but to post saying that complying is wrong is just stupid. You have failed to comply with 542.4 if bonding does not go back to MET.

 
If you can not be bothered to comply with the regs that's one thing but to post saying that complying is wrong is just stupid. You have failed to comply with 542.4 if bonding does not go back to MET.
Ian. Bonding is going back to the MET via the Earth Marshalling Terminal in the C.U and via the combined cpc/Bonding conductor ,as already stated....I am bothered [as you eloquently put it],about complying with BS 7671 ,and the advice given does in fact do just that .............and furthermore is not ,as you put it, Stupid.. .Extract above is taken from The Electrical Safety Councils Essential Guide to The Wiring Regulations .

a1Spark

 
Plumber is correct - that's my tuppence worth, so let's go ha ha ; \

 
Sorry to cut in on your discussion but if the 6mm main earthing conductor runs from cutout (in porche) to cu in cupboard under stairs would it be possible to cut it in the cupboard rather than cut it at front of house, put the met in there and run 16mm from there to cu. Will that comply? I know the other option cut it near cutout would be better but possibly means the house will have to be ripped apart badly.

Also if the tails are 16mm (assuming main fuse is a 60a) can the main earth be 10mm as someone stated above. Will that comply?

Thanks for any pointers and sorry for butting in on your debate?

Cheers all

 
matty your thoroughly nice bloke. its your thread lol

matty you can change the earth if you can change it in such a manner as to not mechanically or electrically infringe its connection as made by the dno.

as its tncs i'm presuming its fairly new and has a means of earthing connection block anyway thats readily accessible and not sealed in a manner to prevent access

 
Regarding A1`s quote (from, if i`m not mistaken, the ESC`s "technical manual CD") ;

The quote refers to another BUILDING; not an earth marshalling terminal within the same building; therefore I`m unsure of the relevance to the thread?

I generally notify DNO that EC is undersized, and inaccessible within the HED. I`ll terminate my 16mm (or whatever) as close as practicable, with enough slack to reach the PME terminal when DNO come out.

I`m still not finished reading up on this; so I`m not getting into the rest of it yet.......

 
debate a side and an attempt to actually help you progress with this work.

its a judgement call matty.

and what we'd call scraping the bottom of the barrel.

if you "need" the work,the client "wants" a new fuseboard but does not want any other work doing regardless of what will/wont comply afterwards, as long as the installation isn't left in any less of a compliant way as it was before then your good to change the CU. you will of course have advised the client of the by the letter route which his is refusing/unwilling to go with.

so i would make a report with this fact and get him to sign a copy you both keep aswel as brief mention on the cert.

now the EIC will say you shouldn't be doing the change but hey they are being feed and paying there mortgage and so you need to.

as a laymans view you will be making the installation massively safer with purely rcd protection of every circuit versus the previous 3036's

dam you would even be justified to put a recommended inspection of 6-12 mths in the hope the client see's light or/and he has redecoration plans or the property has changed hands to someone more willing

 
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