16mm or 6mm

[Buzz-light-bulb]

Hi all

Im currently on with a condition report and it's a tn-s earthing arrangement with a 6mm coming off the sheath into an earthing block then a 16mm from there to the cu, now would you put 6mm as main earthing conductor as this is worse case or 16mm as it goes into the board. Or shall I put my tin hat on

 

[ChrisElectrical88]

16mm and i will join you in putting my tin hat on.

 

[Hawkmoon]

6mm - behave yourselves :53:

 

[Octopus]

Whats the Ze? I'd say 16mm too. Tin hat firmly on. So if you put 6mm then code it C2 how are you going to upgrade it?

 

[Hawkmoon]

Whats the Ze? I'd say 16mm too. Tin hat firmly on. So if you put 6mm then code it C2 how are you going to upgrade it?

You are reporting on cable size these are surely irrelevant? If you report the main earth as 16mm then that implies all is good...is it?

 

[Octopus]

You are reporting on cable size these are surely irrelevant? If you report the main earth as 16mm then that implies all is good...is it?

So, he's doing an EICR, so theses are not irrelevant. TIf the Ze is within tolerance and the 16mm is from the CU. I wouldn't code it as its OK. IMH

 

[AndyL]

The earthing conductor is what connects your MET to the means of earthing so in this case it is 6mm. You are reporting on what is there.

 

[telectrix]

the main protective conductor connects the installation to the supplier's facility. if the suppliers facility includes a bit of 6mm sweated or otherwise permanently connected to the cable sheath, then that 6mm is part of the supplier's facility and so your answer is 16mm.

 

[Hawkmoon]

What if you remove the 16mm, move the CU closer to the incomer and connect the 6mm directly? This is no different (Ze etc) to what you are saying is ok

IMO if you are questioned later you can justify the 6mm in the report - not so the 16mm

 

[foresite123]

I have had this discussion with a BC inspector before I was able to self notify and he assured me that if the DNOs earth is sweated on then it is the suppliers responsibility.

I had the case of what looked like a 4mm bare piece of cable sweated on .

I kept this as short as possible and connected into an earth bar and then ran my new 16mm up to the consumer unit/.

As long as the Ze reading is good then you have nothing to worry about.

Record 16mm as your earthing

 

[Amp David]

What if you remove the 16mm, move the CU closer to the incomer and connect the 6mm directly? This is no different (Ze etc) to what you are saying is ok

IMO if you are questioned later you can justify the 6mm in the report - not so the 16mm

But anyone with any brains wouldn't do this.

The 6mm is the suppliers side, 16mm the installation side

I wouldn't coding it as if you play by the rules, the 6mm shouldn't be touched unless your the DNO:-(

If it worries you that much then just make a comment.

Makes me wonder what size the supply tails are to the meter here?

 

[Buzz-light-bulb]

Ze - 0.09
Pfc - 3.0 ka

I will leave comment about the 6mm and put 16mm as main earth. Meter tails are 25mm thanks for your advice all much appreciated

 

[ChrisElectrical88]

As above for me, The 6mm into the earth block is suppliers side and not anything to do with our install, it should be 16mm like i said in my first post as this is the first earth on the consumer side.If your going down the route of defecting the DNO's earth every PME you would have to defect a N-E short.

 

[Hawkmoon]

The 6mm is a cable and forms part of the main earthing conductor, the fact that it is 'sweated on' by whoever, makes no difference - it is the smallest cable so imo should be recorded in the form.

Ze values etc have nothing to do with just recording the physical size of a cable - I agree you can write what you want on the form regarding whether it is an issue or not.

 

[Zebra Stripe]

[QUOTE=Hawkmoon;888321]The 6mm is a cable and forms part of the main earthing conductor, the fact that it is 'sweated on' by whoever, makes no difference - it is the smallest cable so imo should be recorded in the form.

Ze values etc have nothing to do with just recording the physical size of a cable - I agree you can write what you want on the form regarding whether it is an issue or not.[/QUOTE]

Hey I agree with the bit in bold, the earthing conductor would be from the MET to either the sheath of incoming supply cable or solid link in neutral block for TN systems. If MET was in CU it would be from CU to sheath and so therefore in Ops case I would put 6mm all day as this is the earthing conductor csa.