bonding gas and water how do you work out when to go up from 10mm to 16mm and so on

[chopper]

were currently doing a job in massive old pub whats going to be a libary, my gaffer says put 10mm bonding to gas and water but how do you actually work out what size is required

 

[IQ Electrical]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

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and that's a new one on me. is the 0.05 only applicable to TN-S then, IQ?

No, it's only applicable between extraneous-conductive parts as in supplementary bonding, the figure does not apply to main protective bonding.

We had a good thread here around a year ago on this very thing.

Have a look at BS7671:2008 and Guidance Note 3 and you can see where the confusion comes from-the key word is between.

 

[malcolmsanford]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

If you look on the forms EIC and PIR forms the sections Main Protective Conductors just ask for a "verified connection" and not for a value. As our learned friend posts it is the terminology once again of our beloved regs that throws us.

 

[ezzzekiel]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

new one on me any links to original thread?
my understanding was bonding should have a resistance upto 0.05ohms (10mm good for about 27metres)

just dug this up from quick search:
bonding serves the purpose of ensuring that no dangerous potential differences can occur. The resistance of such a bonding conductor must be low enough to ensure that its volt drop when carrying the operating current of the protective device never exceeds 50 V

which brings me back to what iq is saying as the above description fits the r<50/ia formula for supp bonding ?

 

[GLENNSPARK]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

That is a totally inane post.

The lad is learning and asking questions on here after completing his training, and by posting that drivel as taught him absolutely nothing, except perhaps the merit of your help.

I have to assume you know everything by now and deem this lads question beneath you, if that is the case, perhaps you will refrain from posting such in-depth replies to subjects that are obviously beneath you.

As you have posted just 15 times in 3 years perhaps your best off as lurker status, and leave replies to peoples questions to those on here that wish to help them

NO...NO...NO...keep him posting please....as i have much to learn too (which is why i keep coming in here)...but i am sure his wisdom will soon baffle us all..............

 

[topquark]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

That is a totally inane post.

The lad is learning and asking questions on here after completing his training, and by posting that drivel as taught him absolutely nothing, except perhaps the merit of your help.

I have to assume you know everything by now and deem this lads question beneath you, if that is the case, perhaps you will refrain from posting such in-depth replies to subjects that are obviously beneath you.

As you have posted just 15 times in 3 years perhaps your best off as lurker status, and leave replies to peoples questions to those on here that wish to help them

He's the first person to successfully make it onto my ignore list!

 

[Deleted member 26818]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

He's the first person to successfully make it onto my ignore list!

Damn, just not applying myself.

 

[malcolmsanford]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

He's the first person to successfully make it onto my ignore list!

Oh don't ignore me TQ .........................please

 

[topquark]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

Oh don't ignore me TQ .........................please

Never, unfortunately for you Malc

 

[SPARTYKUS]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

HelloPage 74, GN3, 3.10.3 "detailed periodic inspecting". 4th para down :"When testing the effectiveness of main equipotential bonding conductors, the resistance value between a service pipe or other extraneous-conductive-part and the main earthing terminal should be of the order of 0.05 Ohms or less"Can't see the confusion there...? Am I missing something. Seems clear to me....

 

[IQ Electrical]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

HelloPage 74, GN3, 3.10.3 "detailed periodic inspecting". 4th para down :"When testing the effectiveness of main equipotential bonding conductors, the resistance value between a service pipe or other extraneous-conductive-part and the main earthing terminal should be of the order of 0.05 Ohms or less"Can't see the confusion there...? Am I missing something. Seems clear to me....

Spartykus, I know what you are referring to here but read it again carefully, where does it say that the resistance of the bonding conductors should be defined?

The measurement is taken between the extraneous-conductive part and the main earthing terminal, you will not find any reference to a resistance limit of the bonding conductors in BS7671 or any of the Guidance Notes.

 

[telectrix]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

however, the extraneous part ( say water pipe) is connected to the MET by means of it's bonding conductor, so by inference, that bonding conductor must have a resistance of 0.05ohms or less.

 

[IQ Electrical]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

however, the extraneous part ( say water pipe) is connected to the MET by means of it's bonding conductor, so by inference, that bonding conductor must have a resistance of 0.05ohms or less.

But that's not allowing anything for a parallel path on the extraneous-conductive part....

 

[IQ Electrical]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

It's a poorly written piece-I've got a meeting with Darrell Locke at the IET on 1st November for the Guidance Note 3 amendment-if he hasn't covered it already, I will certainly be drawing attention to it.

 

[brucelee]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

HI mate get them told wish someone would then there would be less confusion as far as I was aware its below 0.05 as this is what i was taught on 2391 last year and read but now you have said i will have another read properly lol for the umpteenth time

 

[SPARTYKUS]

Re: bonding gas and water how do you work out when to go up from 10mm to 16mm and so

:smile5:Morning:smile5:

IQ - Thanks for your patience. I hope you're not too jaded covering something you've clearly been over before, so thanks for bearing with me. I just wanted to understand why you said what you said, as, has been pointed out by several other (learned) members, and time served sparks I know, they all believe it to be so (the 0.05 Ohms or less for the main bond...etc etc). And also, recently, as BruceLee points out, on 2391 courses (was taught this on mine a few years ago too, and it was in all the text books I fervently acquired ....)

HOWEVER! I have stuck with it, re read it, re re read it, and I agree with you!

It is a very poorly written piece of English. Its a tricky language sometimes and to get to the bottom of it (what is written) requires a clear head and a freshly woken up mind.

I have it now. The text does as you say require 0.05 or less between the MET and the bonding conductor. Or other examples. It does not say (As I believed and have been led to believe by lecturers, text books, etc like Christopher Kitchers) that the, for example, disconnected (with a safely isolated installation of course) 88 metre run of 10mm2 main bond from one end to tuther has to be 0.05 or less. At last. I am with you!

You move in higher circles than me btw. I suspect you are a learned fellow. Again, thank you for your patience :mad2: