I can't see how - since, as I've said, one cannot rely on the path to earth via extraneous-c-ps to facilitate satisfactory ADS. Did you have something else in mind?Can it depend upon supply type?
Kind Regards, John
I can't see how - since, as I've said, one cannot rely on the path to earth via extraneous-c-ps to facilitate satisfactory ADS. Did you have something else in mind?Can it depend upon supply type?
If you are relying on ADS wrt your new CU then you have to have adequate protective equipotential bonding.Slightly re-arranging the clause order, the regulation says that the earthing and bonding must be 'adequate' IF [that is] necessary for the protective measure applied for the safety of the addition or alteration". I still struggle to see how that IF clause would ever be satisfied in relation to bonding (earthing is a different matter).
It was, but ....It was Risteard who mentioned ADS ...
It is , indeed, all I am now considering, but that is because, no, I cannot think of any other 'safety measures' (relating to 'the addition or modification') which 'need to be thought about'. Can you think of any (say, in the case we were considering, when the 'addition or modification' is the replacement of a CU)?....and that is all you are now considering. ADS is not mentioned in 132.16. Are there not other safety measures to be thought about?
It would, but that would obviously be a false premise. I need not tell you that earthing and main bonding exist for two totally different purposes. Earthing is, indeed, crucial to 'safety measures' (particularly ADS) but, as BAS wrote, the purpose (and, I believe, the sole purpose) of main bonding is to minimise possible PDs between exp[osed- and extraneous-c-ps - something which is very rarely (if ever) going to have anything to do with (or will influence in any way) 'safety measures' associated with the 'additions or modification' one is proposing to do?if you consider "the earthing and bonding arrangements" as one item then it sort of makes sense.
I'm not sure I understand what you are asking. If (as I believe), bonding is never going to be relevant to the safety measures associated with the work to be done, then I don't think the word should appear in that sentence - if that is the case, it surely should only mention earthing?What is the alternative of the sentence beginning with 'Furthermore'? Ignore the first sentence?
What is the title of 411?411.3.1.2 merely says that all extraneous-c-ps must have main bonding - which we all know. It says nothing about such bonding being required to facilitate ADS, and I still cannot think of any reason why it should be required for that purpose.
Well, if the bonding and earthing were found to be inadequate, would that not count?It is , indeed, all I am now considering, but that is because, no, I cannot think of any other 'safety measures' (relating to 'the addition or modification') which 'need to be thought about'. Can you think of any (say, in the case we were considering, when the 'addition or modification' is the replacement of a CU)?
Is that not a safety measure until ADS happens?the purpose (and, I believe, the sole purpose) of main bonding is to minimise possible PDs between exp[osed- and extraneous-c-ps - something which is very rarely (if ever) going to have anything to do with (or will influence in any way) 'safety measures' associated with the 'additions or modification' one is proposing to do?
Perhaps it means one should not consider only earthing but "bonding and earthing" together.I'm not sure I understand what you are asking. If (as I believe), bonding is never going to be relevant to the safety measures associated with the work to be done, then I don't think the word should appear in that sentence - if that is the case, it surely should only mention earthing?
Fair enough - but if you think it should be made adequate, how would you convey that to poeople?To get this back into context, remember that the last thing I'm suggesting is that absent/inadequate main bonding should not be addressed if it is detected at the time of (or immediately before) a CU change. It was you who pointed out that you believed it was the only 'other thing' which the regs required to be dealt with before work such as a CU change (and I'm now questioning whether even that belief is correct).
If earthing was inadequate, then that would certainly count - but, as I keep saying, I don't understand what bonding has got to do with 'safety measures' (relating to 'the addition or modification').Well, if the bonding and earthing were found to be inadequate, would that not count?
Are you including the 'additional protection' of an RCD as being "ADS". If not, then absence/inadequacy of bonding is never going to cause (OPD-mediated) ADS, expect in the extrordinarily situation of an L-CPC fault in the installation happens at the same time as a path of negigle impedance somehow appears between exposed- and extraneous-c-ps.Is that not a safety measure until ADS happens?
That's what it appears to be saying but, as I keep saying, I don't understand. Maybe it is not meant to make sense?Perhaps it means one should not consider only earthing but "bonding and earthing" together.
I think you need to answer that one. My belief is that any/every potentially dangerous fault/problem in an installation should be remedied before new work is done - it is you who appears to thing that it should only apply to earthing and bonding.Fair enough - but if you think it should be made adequate, how would you convey that to poeople? Perhaps by writing "bonding and earthing shall be adequate".
Why do we bother with it, then.If earthing was inadequate, then that would certainly count - but, as I keep saying, I don't understand what bonding has got to do with 'safety measures' (relating to 'the addition or modification').
Is equalising potential until ADS happens because of a fault not a safety feature?Are you including the 'additional protection' of an RCD as being "ADS". If not, then absence/inadequacy of bonding is never going to cause (OPD-mediated) ADS, expect in the extrordinarily situation of an L-CPC fault in the installation happens at the same time as a path of negigle impedance somehow appears between exposed- and extraneous-c-ps.
Therefore your view includes making the bonding adequate.I think you need to answer that one. My belief is that any/every potentially dangerous fault/problem in an installation should be remedied before new work is done - it is you who appears to thing that it should only apply to earthing and bonding.
In general, do you mean? If so, you know the answer to that as well as I do - to minimise the risk of electric shock if simultaneous with a fault that raises the potential of exposed-c-ps to a dangerous level above true earth someone simultaneously touches an exposed- and an extraneous-c-p - an incredibly unlikley, but not impossible, scenario.Why do we bother with it, then.
Yes, in an extremely unlikely set of circumstances. However, as I keep saying, we are not (the reg is not) just talking about 'safety features' in general - and I don't really see that it counts as a safety feature "applied for the safety of the addition or modification" (i.e., in the case we've been discussing, for the safety of the new CU).Is equalising potential until ADS happens because of a fault not a safety feature?
As I have said many times, my view is that any potentially dangerous defects should be remedied before major new work is undertaken. You are the one who is saying that it is only necessary (at least, per regs) to deal with deficiencies of 'earthing and bonding'.Therefore your view includes making the bonding adequate.
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