S
Silly Sausage
I think you mean diametrically. :shades_smile:
I think you mean diametrically. :shades_smile:
B
Badged01
Definately not in this case, we are applying it to supplementary bonding and there needs to be a physical connection 
DSkelton
Incorrect Regulation 543.2
Incorrect Page 157 BGB
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?
Again, strange that, i assume you will be utilising 543.2
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.
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
Incorrect Regulation 543.2
Incorrect Page 157 BGB
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?
Again, strange that, i assume you will be utilising 543.2
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.
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
........
Definition of supplementary in English:
supplementary
Line breaks: sup|ple¦men|taryPronunciation: /ˌsʌplɪˈmɛnt(ə)ri
/
ADJECTIVE
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
S
Silly Sausage
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
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G
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.
;-)
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.
;-)
R
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.
Good debate this which gave some interesting points of view.
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.
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B
Badged01
Good, you've not gone over to the 'dark' side then!
(Comment passed whilst sat on the boundary watching the match with a beer)
R
rattlehead85
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.
G
Geoffsd
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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.
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.
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.
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.
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Still in the BGB mate.
G
Guest55
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
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.
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.
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.
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if that makes sense ( the moretti has been flowing :8
B
Badged01
And round in circles we go .......
S
Silly Sausage
R
rattlehead85
Seeing as i started the debate i would like to close it by saying that i have to agree wholeheartedly with Chris, badged01 and biff on the subject. I'm not saying or suggesting that what Geoff or DSkelton offer up is wrong merely that there interpretation seems to miss the point that section 7 of BS7671 asks for SB to be applied if the 3 conditions are not met. The points put forward by badged01 define very clearly what section 7 asks for. Regardless of any satisfactory results gained during tests proving that the resistance is low enough, the crux of the matter is that SB is REQUIRED in a room containing a bath or shower.
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B
Badged01
Im happy to accept the views of anybody if this damn thread is closed and put to bed ...... its turned out to be like opening a whole can of worms!
R
rattlehead85
The End.....
G
Geoffsd
Nooooooooooooooooooooooooooooooo. You cannot end it on such a flawed statement.
This is not an interpretation; that is what it says.
All RCBOs are RCDs but not all RCDs are RCBOs.
You must apply 415.2 unless the three conditions are met.
This is not an interpretation; that is what it says.
All RCBOs are RCDs but not all RCDs are RCBOs.
Geoff you are clearly very opinionated. Its pretty simple, 701 require SB to 415.2, it then modifys and supplements it with further requirement's.
1) it asks for Local, this isn't mentioned in 415.2, its supplementary.
2)it asks for the SB to be connected to the terminals of the protective conductors of equipment in the location and to be connected to extraneous parts either in the location or at entry.
Its pretty explicit and clear.
Now your touch voltage concept id flawed, it obeys ohms law, end of, there no debate to be had.
The original IEC uses Ut= If(max fault current) x Rbw(resistance of cable), its been adjusted to 50/Ia by BS7671 based on certain assumptions. Now using your method Ut(touch voltage) will be a product of (If), it may result in Ut be greater than 100 volts, even 150 volts
Now install a SB and we have a Current divider, assume little current flow in the SB in relation to R2 and we have a very low Ut(touch voltage).
Little knowledge can be dangerous, don't play with touch voltages unless you fully understand them, and to advise people SB is not required, well what can i say.
Chris
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Makes u wonder. If us qualified experienced electricians have different views. How does a Electrical Trainee think :-(
They don't, the OSG gives them the wire-by-numbers diagrams that they need
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