EICR and Supplementary Bonding.

[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!