EICR and Supplementary Bonding.

[Silly Sausage]

... diagonally opposed to each other ...

I think you mean diametrically. :shades_smile:

 

[Badged01]

Definately not in this case, we are applying it to supplementary bonding and there needs to be a physical connection

 

[Chr!s]

DSkelton

Just because there is no visual sign of supplementary bonding doesn't mean it isn't there. There is no requirement for the terminations to be accessible or visible, therefore an assumption can be made that supplementary bonding is present and adequate if R≤50V/Ia. The lack of RCD makes for a C3 only.

Incorrect Regulation 543.2

A supplementary bonding conductor is not a protective bonding conductor.

Incorrect Page 157 BGB

It is not there to equalise the potential between exposed and extraneous conductive parts in the event of a fault, it is there to supplement the main protective bonding in its duty of equalising the potential between parts.

It's there to reestablish the equipotential zone, hence why its referred to in 701.415.2 as LOCAL SUPPLEMENTARY BONDING!

Example, Ze 0.02,Circuit to bathroom, 4mm twin earth, cpc 2.5, 25 meters long, Exposed conductive part and extraneous conductive part with the bathroom, whats the touch voltage?

BS7671 doesn't define a supplementary bonding conductor as protective, because it isn't! Lol

I think this is where the flaws in your understanding of its purpose stems from.

Again, strange that, i assume you will be utilising 543.2

The application of a supplementary bonding conductor is to add to the protection given by a main bonding conductor, a supplementary bonding conductor on it's own has no application whatsoever.

Completely wrong, take the bathroom example above, upon fault a voltage will appear on the exposed conductive part, if this is supplementary bonded to the extraneous part then the touch voltage will be dramatically reduced.

And that my friend is the crux of the matter really isn't it!

Hard to see why others seem to struggle with this concept!

Read 700 General BGB, page 197
The special locations in part 7 supplement or modify the general requirements

So we meet 415.2 as required and then we modify and supplement with the requirements of 701


If you don't know the answer to the touch voltage, its 135 volts, but that's okay it meets 50/Ia.

That's why we apply LOCAL SUPPLEMENTARY BONDING!!

There are a host of other issues, i'm not going into anymore, i suggest you speak to the IET because what you are suggesting may put lives at risk!!!


Chris

 

[D Skelton]

DSkelton


Incorrect Regulation 543.2

I disagree

Incorrect Page 157 BGB

I disagree

It's there to reestablish the equipotential zone, hence why its referred to in 701.415.2 as LOCAL SUPPLEMENTARY BONDING!

I disagree, the equipotential zone should already be there, it is there to supplement it

Example, Ze 0.02,Circuit to bathroom, 4mm twin earth, cpc 2.5, 25 meters long, Exposed conductive part and extraneous conductive part with the bathroom, whats the touch voltage?

50V?

Again, strange that, i assume you will be utilising 543.2

No, I'll be utilising the oxford english dictionary definition of supplementary

Completely wrong, take the bathroom example above, upon fault a voltage will appear on the exposed conductive part, if this is supplementary bonded to the extraneous part then the touch voltage will be dramatically reduced.

I disagree

Read 700 General BGB, page 197
The special locations in part 7 supplement or modify the general requirements

So we meet 415.2 as required and then we modify and supplement with the requirements of 701

And your point is?

If you don't know the answer to the touch voltage, its 135 volts, but that's okay it meets 50/Ia.

Huh, maximum touch voltage is 50V??? It is the maximum allowed fault voltage that could appear on exposed metal work if their were a earth fault on that circuit before the protective device operates.

That's why we apply LOCAL SUPPLEMENTARY BONDING!!

No, we apply it to SUPPLEMENT the existing main protective bonding.

There are a host of other issues, i'm not going into anymore, i suggest you speak to the IET because what you are suggesting may put lives at risk!!!

Haha, will it? Really? Funny that, because the IET seems to agree with me on this subject?!

Chris

........

 

[Jay Sparks]

Definition of supplementary in English:


supplementary

Line breaks: sup|ple¦men|taryPronunciation: /ˌsʌplɪˈmɛnt(ə)ri
/
ADJECTIVE

• Completing or enhancing something:the programme offers supplementary information about the newsthe development of databases supplementary to existing ones
• SYNONYMS
• additional, extra, supplemental, increased, further, more; add-on, complementary, subsidiary,accessory, auxiliary, ancillary, supportive, reserveView synonyms
  appended, attached, added, extra, accompanying, annexed, adjunctView synonyms
  
  
  

 

[Silly Sausage]

Just because there is no visual sign of supplementary bonding doesn't mean it isn't there. There is no requirement for the terminations to be accessible or visible, therefore an assumption can be made that supplementary bonding is present and adequate if R≤50V/Ia. The lack of RCD makes for a C3 only.

Taking 526.3 & 543.3.2 into account, and BS951 clamps are of a non MF nature; if SB wasn't visible on a decent install, I would say it is fair enough to assume that there isn't any.

 

[spark 68]

Taking 526.3 & 543.3.2 into account, and BS951 clamps are of a non MF nature; if SB wasn't visible on a decent install, I would say it is fair enough to assume that there isn't any.

Interesting point Re-accessibility Archy 526.3,

The 15th ed 526 refers to non-flexible cables, or a joint between a non-flexible and a flexible cable, that edition also specifically excludes protective conductors in 527 (more about containment and enclosure in building fabric etc.)

In the 16th amd 2 526-03 refers to specifically to live and PEN conductors, and connections in an enclosure, 526-04 is about general accessibility of connections in that edition, so that is similar to the 17th. in that respect. 527 is mainly about fire propagation in that edition.

So while inaccessible sup bonding my not comply with the 17th, it may do with an earlier edition, the 16th underwent several re-writes too

We have all come across bonding clamps under the floor boards and behind sink units, under baths etc. at one time or another.

If a decent install complied to an earlier edition and tested out ok between ECPs I would assume it was fitted, after all we are often told on here that before the advent of the Electrical Trainee the sparks of the time were superior in every way. lol

 

[Guest55]

fantastic technical debate , chapeau to all contributing parties.

but like most epically long threads , the original question is lost , so im going back to read it again.


yep , its still clear.

an inspection carried out at a private dwelling highlighted multi non rcd protected bathroom circuits.
no local supp. bonding was visually evident at any accessory or any exposed metalwork.
its a C2 all day long.

unless someones trying to suggest , in the complete absence of any official guidance whatsoever , is that once supp. bonding cant be visually confirmed , that the inspectors next step is to start randomly carrying continuity tests between bits of metal in the bathroom , in the hope that good readings can now justify a defect reduction to C3 ??

get real.
;-)

 

[rattlehead85]

Yep C2 is what i have always attributed to a situation like this but when i was cross examined by somebody who claimed it was only a c3 coz the readings i obtained where acceptable i started to question my own judgement to the point where i thought i had it wrong!!
Good debate this which gave some interesting points of view.

 

[spark 68]

fantastic technical debate , chapeau to all contributing parties.

but like most epically long threads , the original question is lost , so im going back to read it again.


yep , its still clear.

an inspection carried out at a private dwelling highlighted multi non rcd protected bathroom circuits.
no local supp. bonding was visually evident at any accessory or any exposed metalwork.
its a C2 all day long.

unless someones trying to suggest , in the complete absence of any official guidance whatsoever , is that once supp. bonding cant be visually confirmed , that the inspectors next step is to start randomly carrying continuity tests between bits of metal in the bathroom , in the hope that good readings can now justify a defect reduction to C3 ??

get real.
;-)

Biff may I point you to this part (high-lighted in the text), which was the guidance issued by the ESC, albeit not in the BGB.
This was in the older version of the BP guides, I will have a look and see if it is in a newer version.

 

[Badged01]

Yep C2 is what i have always attributed to a situation like this.....

Good, you've not gone over to the 'dark' side then!

(Comment passed whilst sat on the boundary watching the match with a beer)

 

[rattlehead85]

Biff may I point you to this part (high-lighted in the text), which was the guidance issued by the ESC, albeit not in the BGB.
This was in the older version of the BP guides, I will have a look and see if it is in a newer version.

That is referring to between extraneous pipework not between circuitry and extraneous within the location. As has been repeated so many times..'if there is no SB in place the continuity test to prove its effectiveness ( r<_50v/Ia) cannot be applied.

 

[spark 68]

Where in that document/text does it say between pipe work ?

 

[Geoffsd]

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[Gavin A]

My spark's nicked my BGB to study for a course, but in the BRB it's crystal clear what the situation is as far as I can see.

415.2.2
Where doubt exists regarding the effectiveness of supplementary equipotential bonding, it shall be confirmed that the resistance R between simultaneously accessible exposed-conductive parts and extraneous conductive parts fulfils the following criteria:

R< or = to 50V/Ia in AC systems

Where Ia is the operating current in amperes of the protective device - for over current devices the current causing the automatic operation in 5s.

And yes this does apply for the special location because at the start of 701.415.2 it specifically references Regulation 415.2.

Unless this has actually been removed from the BGB, I'm a bit puzzled as to how this thread has ended up as 8 pages of arguing.

 

[Gavin A]

unless someones trying to suggest , in the complete absence of any official guidance whatsoever , is that once supp. bonding cant be visually confirmed , that the inspectors next step is to start randomly carrying continuity tests between bits of metal in the bathroom , in the hope that good readings can now justify a defect reduction to C3 ??

get real.
;-)

see above, that's exactly what BS7671:2008 states, if this has changed in the update then fair enough, but I'm not aware of that change... sure someone who hasn't had the BGB nicked by their spark will confirm it one way or the other.

eta - at least that's how I'm reading it, I'm sure someone will be along shortly to tell me I'm wrong, in which case I hope they'll actually supply the refences that clearly show why.

 

[spark 68]

see above, that's exactly what BS7671:2008 states, if this has changed in the update then fair enough, but I'm not aware of that change... sure someone who hasn't had the BGB nicked by their spark will confirm it one way or the other.

Still in the BGB mate.

 

[Guest55]

Biff may I point you to this part (high-lighted in the text)

Note: where the presence of supplementarybonding cannot be confirmed by inspection, it
may be verified by a continuity test ** (< 0.05 ohm) **

fair enough , but in post #1..........

Between pipework and metal light carcass **0.44ohms

Between pipework and downflow heater circuit cpc** ​0.26ohms.

so im still giving it C2.............

 

[Gavin A]

Still in the BGB mate.

cheers, so what's the chances of this now being settled then?

I'd have a fiver on someone trying to say that this only applies after a visual inspection has confirmed the presence of the green and yellow cable with the correct tags on it, so I'll preempt by pointing at 544.2.4

Supplementary bonding shall be provided by a supplementary conductor, a conductive part of a permanent and reliable nature, or by a combination of these.

Assuming that the pipework isn't ****ing water everywhere, it can reasonable be assumed that the probably soldered or compression joints in the copper pipe are of a permanent and reliable nature, and the conductance has been verified by testing.

I'm sure that's been referenced before on this thread already though.

 

[jamie-spark]

this has been a great thread. Its good to see respected members have different views on supplementary bonding ( its not just us plebs that find the application/wording/definitions not ideal to understand at first)
i too thought/think that supplementary bonds had to be in place ( ie see visual confirmation from extraneous conductive parts to exposed conductive parts)
i have GN5,7 and 8 and will certainly be looking over it in the next few days( may take a week for my wee brain to compute it all ) and will give a better judgement on my fence side then.