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?
Kind Regards, John
Best option going forward. Install cert.
- Thread starter ThrottleHappy
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Kind Regards, John
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Just wondering whether the absence of PEBs on a TN-C-S suppy came into it.
If you are relying on ADS wrt your new CU then you have to have adequate protective equipotential bonding.
I still don't really understand. If one is 'relying on ADS', then that ADS must be effective without any 'help' from bonded extraneous-c-ps. As I thought had been (correctly) asserted, the (and I think only) purpose of main bonding is to minimise the possible pd between exposed and extraneous-c-ps, and that has nothing to do with the effectiveness of ADS. Bonded extraneous-c-ps may reduce EFLI and therefore 'aid' ADS but, as I said, one must not rely on that.
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411.3.1.2
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.
It was Risteard who mentioned ADS 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?
I have long thought that main bonding was one thing that did not fall under "not retrospective" regulations. Perhaps I was mistaken.
I agree it is another example of poorly written regulations, but
if you consider "the earthing and bonding arrangements" as one item then it sort of makes sense.
You cannot argue that because the bonding is not contributing to ADS that it can be ignored when reading the first sentence of 132.16.
ADS being not the only safety measure.
Also "safety of the addition or alteration" does not, I think, mean the actual parts being added or altered (CU in this case) but obviously the installation as a whole and the users.
What is the alternative of the sentence beginning with 'Furthermore'? Ignore the first sentence?
It's possibly like the recent thread which you did not accept; just an unnecessary addition.
ADS is not mentioned in 132.16. Are there not other safety measures to be thought about?
I have long thought that main bonding was one thing that did not fall under "not retrospective" regulations. Perhaps I was mistaken.
I agree it is another example of poorly written regulations, but
if you consider "the earthing and bonding arrangements" as one item then it sort of makes sense.
You cannot argue that because the bonding is not contributing to ADS that it can be ignored when reading the first sentence of 132.16.
ADS being not the only safety measure.
Also "safety of the addition or alteration" does not, I think, mean the actual parts being added or altered (CU in this case) but obviously the installation as a whole and the users.
What is the alternative of the sentence beginning with 'Furthermore'? Ignore the first sentence?
It's possibly like the recent thread which you did not accept; just an unnecessary addition.
It was, but ....
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)?
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?
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?
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).
Kind Regards, John
What is the title of 411?
I know what the title of 411 is, but I'm still waiting for someone to explain to me what main protective bonding has got to do with ADS. I'm very willing to learn.
Well, if the bonding and earthing were found to be inadequate, would that not count?
Is that not a safety measure until ADS happens?
Perhaps it means one should not consider only earthing but "bonding and earthing" together.
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".
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').
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.
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?
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.
Kind Regards, John
Why do we bother with it, then.
Is equalising potential until ADS happens because of a fault not a safety feature?
Therefore your view includes making the bonding adequate.
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.
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 it perhaps just that (again) we are talking about a very badly worded regulation?
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'.
Kind Regards, John
No, I didn't say it was the only one necessary.
I said I thought it was a regulation that it should be brought up to date; i.e. not 'not retrospective'.
I have said I may have been mistaken - but I don't know if I was.
If you interpret a badly written regulation different than I, then, as you often say, you will have to ask them.
I said I thought it was a regulation that it should be brought up to date; i.e. not 'not retrospective'.
I have said I may have been mistaken - but I don't know if I was.
If you interpret a badly written regulation different than I, then, as you often say, you will have to ask them.
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