EICR and Supplementary Bonding.

[Badged01]

And we go round in circles! OK, I have my view and you have your view and there is enough information in the thread for a 3rd party to draw there own conclusions.

Stumps drawn, Im taking my bat & ball home .........

 

[Des 56]

Has this thread discussion concluded so soon ?

For anyone who wants to read IET guidance and history, in order to wade in to this subject
Its from past editions and gives the timeline of change and requirements


Click on the item in issue 27 summer 2008
Wiring Matters - 2008 issues - IET Electrical

413-7 is interesting regarding some of the views posted in this thread

 

[rattlehead85]

I didn’t want to end up with a lengthy and boring to and fro thread but feel you are completely off course in your interpretation/understanding of the application and need for supplementary equipotential bonding. Nowhere can I find anything that states supp bonding is not required if the impedances are low enough to limit meet the touch voltage requirement.

Section 701 states additional protection in the form of supp bonding SHALL be established connecting protective conductors to accessible extraneous-conductive parts in the location. My interpretation is there has to be a physical connection to achieve this in the location and this is supported by the advice/pictures/drawings in GN8 and the ESC publications.

Change the word “insulation” for “bonding” in the definition of Supplementary in the BGB. This I believe gives a further intent as to application of supplementary. That is supp bonding is applied in addition to main bonding for fault protection. (“applied” I interpret as meaning a physical connection as with main bonding.)

If main bonding is fitted you will always get a reading in the bathroom to showing continuity and 90% of the time it will meet touch voltages (assuming continuity of metalwork). Hence a reading alone will not prove supplementary bonding is physically present. You need to see it to confirm its presence.

Once you can see supp bonding, if you have any doubt as to the “effectiveness” of that supp bonding then you can test as per 415.2 using said touch voltage equation. No where in the regulations can I see anything that suggests this test alone is a substitute for confirming sup bonding is present, just “effective”. Its application is purely as a test if not sure that the supp bonding is “effective” in providing additional protection. (i.e. you’ve seen it and now want to test to confirm compliance.)

Even to apply this equation in practice, for me you have to be able to physically disconnect an end of the sup bonding and test, because if you have any bonding elsewhere in the premises your results will be effected by parallel paths. So if sup bonding isn’t there in the first place you cant prove its effectiveness just by using the equation?

At the end of the day sup bonding is there as an additional fault protection method and if you cant confirm its presence (not effectiveness) by the good old mark one eye-ball then no testing to an equation will convince me it is, just hidden somewhere. Lack of sup bonding can have serious implications in a fault situation should for example main bonding be lost, hence why the ESC consider lack of its presence being a C2 without an RCD fitted??

If there is anything in the regulations that Ive missed or goes against anything Ive stated then please advise and correct me. I am always learning and seeking new knowledge and understanding.

This is a very good opinion offered and makes good sense.

 

[Geoffsd]

Unfortunately it is fundamentally flawed and

contradicts your original question which, without option 1, was entirely correct.

 

[rattlehead85]

Flawed.... it's his interpretation and i can see his point. I still see a valid argument for both sides but to be honest the regs and GN both clearly define Supp bonding as being required in a room containing a bath or shower...not as required only if a test to confirm r<50v/Ia is not met which indicates that the test to verify r<50v/Ia is only used to confirm if the bonding required is effective.

 

[rattlehead85]

So....interpreting the regs in this way the scenario i originally put forward would clearly warrant a code 2 departure as there is no RCD, no required bonding in the location as stated by 7671 section 7 and therefore the test i applied cannot be classed as valid because there was no evident supplementary bonding in place to apply the test to.

 

[Guest55]

So....interpreting the regs in this way the scenario i originally put forward would clearly warrant a code 2 departure as there is no RCD, no required bonding in the location as stated by 7671 section 7 and therefore the test i applied cannot be classed as valid because there was no evident supplementary bonding in place to apply the test to.

yep pretty much what i said in my first post many pages ago , but some folk just wanna talk & argue in circles for the sheer sake of it.

 

[telectrix]

still better than discussing fans on showers and RCDs in series.

 

[Geoffsd]

Alright, last post - but just make sure it IS extraneous before applying unnecessary bonding.

So....interpreting the regs in this way the scenario i originally put forward would clearly warrant a code 2 departure as there is no RCD, no required bonding in the location as stated by 7671 section 7 and therefore the test i applied cannot be classed as valid because there was no evident supplementary bonding in place to apply the test to.

You have said 'required' so what if it is not required?

Flawed....

Yes.

it's his interpretation and i can see his point. I still see a valid argument for both sides but to be honest the regs and GN both clearly define Supp bonding as being required in a room containing a bath or shower...not as required only if a test to confirm r<50v/Ia is not met which indicates that the test to verify r<50v/Ia is only used to confirm if the bonding required is effective.

But that is the same thing.

415.2.2 states Where doubt exists regarding the effectiveness of supplementary bonding, it shall be confirmed that the resistance R between simultaneously exposed-conductive-parts and extraneous-conductive-parts fulfils the following condition: R ≤ 50/Ia (or I∆n)

Presumably if visible, doubt does not exist,

So, ≤ 50/Ia means the SB is effective where doubt exists.

Therefore, if the parts themselves give a reading of ≤ 50/Ia then do you not still agree, as you stated in your first post, that supplementary bonding is not required.




It's the same as applying another CPC to a circuit because you cannot see where the conduit goes even though the Zs is satisfactory.

 

[Chr!s]

Its simple, no RCD, then Supplementary bonding required between exposed and extraneous.

Chris

 

[D Skelton]

Its simple, no RCD, then Supplementary bonding required between exposed and extraneous.

Chris

Correct. And if you can't see whether or not it is present then you test and apply the R<50V/Ia rule to see if it is there but hidden or as good as being there.

 

[Chr!s]

Correct. And if you can't see whether or not it is present then you test and apply the R<50V/Ia rule to see if it is there but hidden or as good as being there.

I can see your point, but i have to disagree there, not sure why upon an inspection SB wouldn't be evident, saying that if its not established then the assumption must be that there isn't any.

Chris

 

[Chr!s]

I think yourself and geoffsd need to look at the requirements a little closer, the point you are both making would be none compliant.

Chris

 

[Gavin A]

IET agrees with Geoff and D Skelton.

DISCONNECTION TIMES Regulation 411.3.2.6 states that where automatic disconnection cannot be achieved in the required time, supplementary equipotential bonding shall be provided

Do bear in mind that supplementary equipotential bonding need not be physically carried out by the installation of single core green and yellow conductors in every instance.

There may be a situation where for example, two simultaneously accessible metallic parts are in reliable contact and the resistance between the two parts is sufficiently low.

IET - wiring matters

Stands to reason really, if supplementary bonding exists in order to bring the potential difference down to below 50V, then if the potential difference is measured at being below 50V then that requirement is already met.

 

[Chr!s]

IET agrees with Geoff and D Skelton.


IET - wiring matters

Stands to reason really, if supplementary bonding exists in order to bring the potential difference down to below 50V, then if the potential difference is measured at being below 50V then that requirement is already met.

No its not the IET's interpretation, its your misinterpretation

Chris

 

[Geoffsd]

As you have resurrected the thread I will say that it's not a misinterpretation and I'm afraid it is you, Chris, who doesn't understand.

I don't know how else to persuade you especially as Gavin's post sums it up perfectly.



May I ask you, if SB must be applied regardless, and so reducing the impedance between parts to virtually negligible, then what do you think is the reason for even mentioning 50/Ia in the regulations?



Just please don't apply SB to any isolated parts.

 

[Badged01]

Now the thread is going at a tanget to the original question ref supp bonding in a bathroom viz section 701 so Ive brought my bat and ball out for one last play!

Gavin A is absolutely correct that if disconnection times cant be met under the protective measure of ADS then 411.3.2.6 applies and supp bonding can be used IAW 415.2 and the 'equation' applies. Supp bonding can now be anywhere in the installation and there is no requirement for specific location of bonding.

But is the original question raised by the thread about the bathroom not meeting disconnection times or the requiremnt in a special location? In a special location supp bonding as applied to bathrooms under 701 and has a totally different application to meeting disconnection times. 701 is specific to physical connections within the bathroom (or close by) with supporting interpretation within GN8 making this fairly clear.

Had my innings, bat and ball going home again .......

 

[Chr!s]

As you have resurrected the thread I will say that it's not a misinterpretation and I'm afraid it is you, Chris, who doesn't understand.

I don't know how else to persuade you especially as Gavin's post sums it up perfectly.



May I ask you, if SB must be applied regardless, and so reducing the impedance between parts to virtually negligible, then what do you think is the reason for even mentioning 50/Ia in the regulations?



Just please don't apply SB to any isolated parts.

Okay Geoff shall we deal with section 701 as the start, seeing how this was the op's concern?

So we have an installation which has NO RCD, the bathroom has simultaneous exposed and extraneous conductive parts, but NO supplementary bonding present.

A test was carried out between all conductive parts and it was found that the resistance met that of 50/Ia, therefore no Supplementary Bonding is required.

Is this your and DSkeltons interpretation?

 

[rattlehead85]

Well....the posts on this thread have given me some good guidance to the point where i can say that a C2 should be the code used coz there was no RCD and no bonding present as requested by the BGB for a room containing a bath or shower. As i mentioned before the test used to confirm r<_50v/Ia cannot be considered as there was no bonding present in the first place to apply it to!! the readings i obtained could quite easily be due to a fortuitous connection somewhere within the installation which can in no way be considered as satisfactory or constantly reliable.

 

[Geoffsd]

Chris, you have not answered my question but ok.



As it is a special location 701.415.2 states that -

Local SEB according to 415.2 shall be established...
SEB may be installed outside or inside rooms containing a bath or shower, preferably close to the point of entry of e-c-ps...

Anything else?



Surely 415.2 is the more relevant to what is being discussed and has been (all but) quoted in its entirety.

 

[Chr!s]

Chris, you have not answered my question but ok.



As it is a special location 701.415.2 states that -

Local SEB according to 415.2 shall be established...
SEB may be installed outside or inside rooms containing a bath or shower, preferably close to the point of entry of e-c-ps...

Anything else?



Surely 415.2 is the more relevant to what is being discussed and has been (all but) quoted in its entirety.

Hi Geoff, well just that my assumption of your interpretation is correct, i assume that its is?

 

[rattlehead85]

Can i just add at this point that in no way was i intending to instigate any sort of fall out between members here...it just goes to show though that there should be a more concise and clear understanding of this matter provided by the powers that be so threads like this need not cause such debate and varied opinions in the first place.

 

[Chr!s]

Hi Geoff

So you mention 701.415.2, lets look at what it require's

SB according to 415.2, connecting together the TERMINALS OF THE PROTECTIVE CONDUCTOR of each circuit supplying Class 1,2 equipment to the accessible extraneous conductive parts, within a room containing a Bath or shower.

So the terminal of the protective conductor within the location need connecting to the extraneous within that location.

It goes on to say that the connection to the extraneous parts MAY be made outside the location, preferably close to the entry.


Which Regulation negates the requirement of 701.415.2 in regard to the connection of SB to the protective conductors of the equipment within the location?

Chris

 

[Geoffsd]

So you mention 701.415.2, lets look at what it require's

What else is there?

SB according to 415.2, connecting together the TERMINALS OF THE PROTECTIVE CONDUCTOR of each circuit supplying Class 1,2 equipment to the accessible extraneous conductive parts, within a room containing a Bath or shower.

To limit touch voltage to 50V.

So the terminal of the protective conductor within the location need connecting to the extraneous within that location.

If touch voltage is more than 50V.

It goes on to say that the connection to the extraneous parts MAY be made outside the location, preferably close to the entry.

Yes, not sure of your point.
I thought that was my point to explain the absence IN the room.

Which Regulation negates the requirement of 701.415.2 in regard to the connection of SB to the protective conductors of the equipment within the location?

415.2.2 states that SB is effective if R≤50/Ia and
542.2.1 states that a fixed conductor or an extraneous part may be used as a SB conductor so if the parts already satisfy R≤50/Ia then 415.2.2 is met and no Supplementary(additional) Bonding is required.

This would seem to be the only thing we do disagree about so I will ask again - if this is not so and SB must be applied regardless thus reducing the impedance to negligible why is 50/Ia ever mentioned?

With only a lighting circuit in the room and all parts connected by up to 5m. of 4mm² the touch voltage would only be 30x0.023 = 0.69V.
Even with a 40A shower it would only be 200x0.023 = 4.6V.
So why is the limit set at 50V when this would never occur if everything must be bonded regardless?

 

[Chr!s]

Hi Geoff

I've cut the last section try and keep it easier.

415.2.2 states that SB is effective if R≤50/Ia

Agreed

and
542.2.1 states that a fixed conductor or an extraneous part may be used as a SB conductor so if the parts already satisfy R≤50/Ia then 415.2.2 is met and no Supplementary(additional) Bonding is required.

How do you intend to apply that to the requirements of 701? The SB is required to be connected to the Protective Conductor Terminal of the location? And i assume 543.2.1?

This would seem to be the only thing we do disagree about so I will ask again - if this is not so and SB must be applied regardless thus reducing the impedance to negligible why is 50/Ia ever mentioned?

Not too sure what you mean, i think you need to be specific with regard the installation. If we take an agricultural location 705,say a large metal shed, if two conducive parts are effectively connected do we need to SB the two, no, your interpretation in that instance is correct, but not with regard 701.

With only a lighting circuit in the room and all parts connected by up to 5m. of 4mm² the touch voltage would only be 30x0.023 = 0.69V.
Even with a 40A shower it would only be 200x0.023 = 4.6V.

What if a greater current was to flow through the bonding conductor

So why is the limit set at 50V when this would never occur if everything must be bonded regardless?

Belt and Braces, ensuring no fortuitous connections, and as you have stated 50 V is what they regard as safe

Chris

 

[Geoffsd]

415.2.2 states that SB is effective if R≤50/Ia

Agreed

But you don't agree that if the R is already ≤50/Ia no more bonding is required. Why would it be?

______________

and
542.2.1 states that a fixed conductor or an extraneous part may be used as a SB conductor so if the parts already satisfy R≤50/Ia then 415.2.2 is met and no Supplementary(additional) Bonding is required.

How do you intend to apply that to the requirements of 701? The SB is required to be connected to the Protective Conductor Terminal of the location? And i assume 543.2.1?

I'm not sure what you mean by keeping asking about 701. That's what we are discussing.
If not required for the above reason then it does not apply.
543.2.1 merely lists parts which may be used as bonding including an e-c-p (pipe) and fixed conductor (cpc).

________________

This would seem to be the only thing we do disagree about so I will ask again - if this is not so and SB must be applied regardless thus reducing the impedance to negligible why is 50/Ia ever mentioned?

Not too sure what you mean, i think you need to be specific with regard the installation. If we take an agricultural location 705,say a large metal shed, if two conducive parts are effectively connected do we need to SB the two, no, your interpretation in that instance is correct, but not with regard 701.

What I mean is - you are stating that SB must be applied (where I think not) in which case the resistance between the parts will always be near negligible so why did they think up the 50/Ia rule. In your world the bathroom would need to be massive to get anywhere near 50V.

________________

With only a lighting circuit in the room and all parts connected by up to 5m. of 4mm² the touch voltage would only be 30x0.023 = 0.69V.
Even with a 40A shower it would only be 200x0.023 = 4.6V.

What if a greater current was to flow through the bonding conductor

That's not the purpose.
All we have to consider is the greatest Ia of the bathroom circuits.
That is the highest current that may flow from a touchable exposed part before the disconnection of the current - 5x6A for lighting or e.g. 5x40A for shower.
To ensure the voltage drop from this exposed part to another part that may be touched is a maximum of 50V, therefore 50V/If ≥ R

________________

So why is the limit set at 50V when this would never occur if everything must be bonded regardless?

Belt and Braces, ensuring no fortuitous connections, and as you have stated 50 V is what they regard as safe

Then why, if that is already met by the installation, are you insisting on reducing it further with additional supplementary bonding which is not required.
The fortuitous connections to which you refer are the very parts to which you want to connect the extra un-required bonding.

 

[D Skelton]

As it is a special location 701.415.2 states that -

Local SEB ACCORDING TO 415.2 shall be established...

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!

 

[Badged01]

I think the thread is going around and around in circles. Two views diagonally opposed to each other -- other than on agreement that 701 & 415 need to be applied in a special location (bathroom).

Enough information from both viewpoints available in the thread for anyone interested in the requirements for supplementary bonding to make their own informed decision!

Can I suggest the thread has run its course and is closed by the moderators??

 

[telectrix]

mods are too busy measuring resistances in their bathrooms.

 

[Badged01]

Excellent, hopefully the mods will then be able to give their own independent assessment based on their field investigations/findings!

 

[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]

.
.
.
.
.

 

[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.