NICEIC Certification Scheme Niceic

[Simon Hall]

Hi I'm doing my nic eic domestic installer, I've done my big job of rewire all done and tested. Now I've got to do a small job I've fitted a new socket which is RCD protected but the main tails from meter to the CU are only 16mm does this mean I will have to change them for 25mm as you do when doing a board change and the earth bonding only looks like 6mm will I need to change that for 10mm as well thanks for your help

 

[Octopus]

Why would you need to change the meter tails? what size is the DNO fuse? As for the equipotential bonding, best you read the regs again.

 

[Geoffsd]

I will have to change them for 25mm as you do when doing a board change

NOT TRUE.

Table 4D1A.

 

[D Skelton]

Another wire by numbers spark trained well in the use of the OSG! :mad2:

It is BS7671 we work to, do please remember that. I honestly believe that these fast track training centres have absolutely no idea of the application of such a document! It seems everyone who passes through one of these training centres has never even picked one up!

 

[cmac70]

Glad I went to collage and not a training centre. We were told from day 1 if you don't get bs7671 you stay me **** list till you do.

 

[NMc]

Why would you need to change the meter tails? what size is the DNO fuse? As for the equipotential bonding, best you read the regs again.

Regulation 544.1.1

 

[D Skelton]

Regulation 544.1.1

Best you read the regs again also!

 

[NMc]

Best you read the regs again also!

and why's that?

 

[D Skelton]

and why's that?

Because a 6mm bonding conductor is going to be perfectly adequate on any domestic TN-S or TT system.

 

[Simon Hall]

It's on a TN-C-S

 

[D Skelton]

First of all, are you sure it's PME and not split concentric TN-S at the service head. You'd be surprised at the number of people who miss this!

Secondly, if you are sure, then yes, the bond needs to be 10mm. You didn't make this clear in your OP though did you?

 

[NMc]

Because a 6mm bonding conductor is going to be perfectly adequate on any domestic TN-S or TT system.

That's correct and what reg 544.1.1 says

TNC-S needs 10mm and always has done

Chances are that if the original bonding was 6mm then it may not be a TNC-S supply but still needs to be confirmed

 

[Simon Hall]

Thanks I'll need to check again heading back over tomorrow

 

[Simon Hall]

.......

 

[D Skelton]

That's correct and what reg 544.1.1 says

TNC-S needs 10mm and always has done

Chances are that if the original bonding was 6mm then it may not be a TNC-S supply but still needs to be confirmed

Oh I'm sorry, I thought you were questioning Murdoch, not confirming what he was saying with the reg number. My apologies.

 

[MDJ]

TNC-S needs 10mm and always has done

Aye I have never liked that reg

 

[Buzz-light-bulb]

Electrical safety council.
When carrying out electrical work on an installation forming part of a TN-C-S system, is it necessary to upgrade existing 6 mm² protective equipotential bonding to 10 mm²?
Not necessarily. If the existing 6 mm² bonding connects all the extraneous-conductive-parts to the main earthing terminal, has been in place for a significant time and shows no signs of thermal damage, then it may not require to be upgraded.

Regulation number(s) 132.16 544.1.1

 

[Engineer54]

That's typical BS7671 for you, it's full of contradictions!!

 

[D Skelton]

The very reason it will never become a statutory document until it can be assured that everyone involved in writing it actually knows what they're talking about!

50% of it is good, 40% of it is far too open to interpretation, 10% of it is just fundamentally flawed.

 

[SPARTYKUS]

...and of course it's nothing to do with the fact that physics laws changed and it became safe to use the neutral as the earth.

but just in case make sure theres a whopping great fat thick bond to the pipes that go in the ground. Just in case. Because it is safe really. Honest. Just kidding. Maybe.