In which case, you already have one; no need for a second.
In your installation, they haven't.
Work on TN installations come "the 18th"
- Thread starter JohnW2
- Start date
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Arguing about what "supplement" means, and wondering why they didn't simply write
is all very well, but nowhere near as important an issue as the definition of "adequate" and whether as written the 18th will require an earth rod to be installed before any work is done.
542.1.201 The main earthing terminal shall be connected with Earth by one of the methods described in Regulations 542.1.2.1 to 3, as appropriate to the type of system of which the installation is to form a part and in compliance with Regulations 542.1.3.1 and 542.1.3.2. Additionally there shall be an earth electrode in accordance with one of the requirements of Regulation 542.2.3, to prevent the appearance ofa dangerous touch voltage in the event of the loss of the main connection to Earth.
is all very well, but nowhere near as important an issue as the definition of "adequate" and whether as written the 18th will require an earth rod to be installed before any work is done.
Unless it is being suggested that there should be a requirement for two earth rods in a TT installation, the last clause of that last sentence wouldn't make a lot of sense - since, if there were only one earth rod, that would surely be the 'main connection to earth'.
As for what work could be undertaken without first installing an earth rod (in a TN installation) (and if the draft reg survives unchanged into the "18th"), that would presumably be down to 132.16 (which is unchanged in the DPC) - and so presumably would relate to any 'addition or modification', whatever that might include (I would suspect everything other than replacement of existing wiring/comments with 'similar').
As for what work could be undertaken without first installing an earth rod (in a TN installation) (and if the draft reg survives unchanged into the "18th"), that would presumably be down to 132.16 (which is unchanged in the DPC) - and so presumably would relate to any 'addition or modification', whatever that might include (I would suspect everything other than replacement of existing wiring/comments with 'similar').
Which would be totally unsustainable, especially for people in blocks of flats.
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As I think I said, about the only sensible option I can think of in the case of a block of flats (or similar situations) would probably be to require than a TN earth was connected to an 'additional earth rod' close to the point of entry into the building and that it would be that 'combined earth' which would then be distributed to the flats. However, I am not at all sure (actually, doubt) that that would be compliant with the reg as worded in the DPC.
Who would pay for/carry out that work?
But it wouldn't necessarily be distributed - yes, in all the flats their N would silently have morphed to CNE, but unless it was already a TN-C-S supply the each flat would remain with a TN-S earth.
But it wouldn't necessarily be distributed - yes, in all the flats their N would silently have morphed to CNE, but unless it was already a TN-C-S supply the each flat would remain with a TN-S earth.
If the incoming supply to the building were already TN-C-S, then the 'additional earth rod' (at entry to the building) would merely be an extra, local, "M" to add to the "PME" (which I suspect may well have been the thinking behind the draft reg). If the incoming supply to the building were TN-S, then what would be distributed to the flats would be a 'TN-S earth supplemented by an additional local earth rod' - which appears to be what the draft reg, as written, would be asking for.
So the supply neutral would be connected to earth before the point of entry to the building (I'm assuming the earth rod would be outside), not one single flat would have its local installation earth connected to the N in its cutout, but every one would have it connected to the sheath of the supply.
Hard to see how that counts as distributing the new earth to the flats....
Hard to see how that counts as distributing the new earth to the flats....
I can't work out whether this comment is about TN-C-S or TN-S. The first part of the first sentence sounds like the former, whereas the reference to "connected to the sheath of the supply" at the end of the sentence suggests the latter.
As I said, I imagine that the thinking behind this draft reg was probably to require a ('local') "ME" (as in PME) to be connected to the neutral of a TN-C-S supply, in case of a neutral failure in the supply network.
As I said, I imagine that the thinking behind this draft reg was probably to require a ('local') "ME" (as in PME) to be connected to the neutral of a TN-C-S supply, in case of a neutral failure in the supply network.
So the supply neutral would be connected to earth before the point of entry to the building (I'm assuming the earth rod would be outside), not one single flat would have its local installation earth connected to the N in its cutout, but every one would have it connected to the sheath of the supply.
Hard to see how that counts as distributing the new earth to the flats....
Common sense says that the ESQCR should be amended to require the earth rod to be connected to the supply neutral on the network side.
Fear ye not. It has not come to pass.
You have information? Most of us have to wait until at least Monday
Kind Regards, John
See link in post at - 28 June 2018 11:01 PM
https://www.theiet.org/forums/forum...hreadid=106136&enterthread=y&STARTPAGE=1#last
https://www.theiet.org/forums/forum...hreadid=106136&enterthread=y&STARTPAGE=1#last
Thanks. Very interesting - but that document surely should not be in the public domain, should it? ("Private Circulation - JPEL/64 Information Only" -
Although that is still only a draft, I can but assume (from the date) that it is the 'final draft', such that it should fairly accurately reflect what will be the published version - but I suppose we still have to wait until Monday to be absolutely certain.
I haven't yet looked in detail at this document, but wonder if you have noticed anything else which has changed since the DPC?
Kind Regards, John
That's why I didn't link to it directly. Best not tell anyone.Thanks. Very interesting - but that document surely should not be in the public domain, should it? ("Private Circulation - JPEL/64 Information Only" -
No, it was late when I saw it.
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