Work on TN installations come "the 18th" - separate issue

[ban-all-sheds]

Ignoring any and all considerations of what would trigger, or when, the addition of a local earth rod, assuming that it was to be done because the requirement in the DPC makes it into the 18th, how would it be done, practically, for someone N floors up in a block of flats?

 

[JohnW2]

Indeed. That's an issue we've discussed before, and no-one seems to have a clue as to how one is meant to handle such a situation. ... The nearest to a sensible solution I can think of would be that the requirement would be to connect an earth rod just to the incoming supply to the building, before it was distributed to the various dwellings within the building - but what it said in the DPC gave no hint about that.

 

[flameport]

Earth rod(s) for the supply to the building, and make the equipotential zone the building as a whole, rather than having each individual flat as it's own EPZ.

 

[JohnW2]

Earth rod(s) for the supply to the building, and make the equipotential zone the building as a whole, rather than having each individual flat as it's own EPZ.

As I said, that's the nearest to a sensible solution/approach I can think of - but the draft regulation, as it appeared in the DPC, appears to require each 'installation' to have an earth rod, and I would imagine that each flat would count as a separate installation. If that is the case, the regulation (whenever it appears) (or the defininition of an 'installation') would presumably have to be tweaked if it were to allow an arrangement such as we have both suggested.

Kind Regards, John

 

[ban-all-sheds]

Widening the scope of an installation to encompass all the flats in a block would have an impractical impact on many other regulations.

If the provision in the DPC makes it into the regs, then even if there are guidelines or clarifications to deal with the have-to-add-an-earth-rod-to-change-a-light-switch problem, sooner or later there will come a case, e.g. complete rewire, where there is no doubt that a supplementary rod is needed. That has to be connected to the flat's MET, on the Nth floor.

 

[davelx]

Widening the scope of an installation to encompass all the flats in a block would have an impractical impact on many other regulations.

If the provision in the DPC makes it into the regs, then even if there are guidelines or clarifications to deal with the have-to-add-an-earth-rod-to-change-a-light-switch problem, sooner or later there will come a case, e.g. complete rewire, where there is no doubt that a supplementary rod is needed. That has to be connected to the flat's MET, on the Nth floor.

My mind's eye sees a buried mesh earthing system for the building, and a BFO busbar up the building's vertical service ducts to which each flat's MET is connected.

Would that comply, I wonder? It's similar to what is used in multi-storey offices etc.

 

[ban-all-sheds]

It would.

So you are the occupier of a flat on the Nth floor, and the first one in the block to be having work done which triggers the requirement for a supplementary earth.

Who is going to install the system you describe, and who is going to pay for it?

 

[davelx]

It would.

So you are the occupier of a flat on the Nth floor, and the first one in the block to be having work done which triggers the requirement for a supplementary earth.

Who is going to install the system you describe, and who is going to pay for it?

The freeholder, as it's part of the building infrastructure that they will likely need to provide to sustain the possibility of future sales of the flats?

Or the leaseholders if they want to be able to sell their flats?

Or a compromise - freeholders provide the buried mesh and vertical busbars, leaseholder pay for their flat to be connected to it as and when they want to have work done that requires it.

If the regs as proposed are implemented (let's hope they are not), someone is going to have to negotiate a solution at some point.

It will make for some interesting meetings between lessees and the management company/freeholders.

 

[ban-all-sheds]

"Interesting" as in "you want your flat rewired/new cooker fitted/CU changed/whatever, you pay for it" conversations, I expect.

 

[JohnW2]

I suspect that if/when this proposal actually gets into the regs (maybe next week, maybe later, maybe never), there will probably have to be some tweaking to cover this situation which, at first sight (per DPC), probably wasn't given enough consideration at DPC stage. If my suspicion is correct, that their primary concern was to have a requirement a 'local' connection to a 'local' earth from a TN-C-S neutral (supplementing what other "M"s the PME had - which I think is a requirement in many/most other countries), then maybe they would decide that it was acceptable for this to be done on a 'per building' basis.

Unless (as has been suggested) ESQCR were amended to require DNOs to provide this for multi-dwelling buildings (which, even if they would 'accept' it, would probably take a long time to achieve), there would still be the problem of what would happen (who would pay) when the first of the occupants of the dwellings needed work done which required the earth rod to be installed - but maybe that burden could be forced upon landlords/freeholders.

 

[skenk]

Am I right in thinking that at the moment (under the 17th) it is prohibited to connect a local earth rod to the PME installation earth?

 

[ban-all-sheds]

Unless (as has been suggested) ESQCR were amended to require DNOs to provide this for multi-dwelling buildings

No, all dwellings/buildings.

The point about the ESQCR is that it would make the DNOs responsible for providing what they should have been providing in the first place.

(which, even if they would 'accept' it, would probably take a long time to achieve)

My view of legislation is that they have no choice but to accept it.

there would still be the problem of what would happen (who would pay) when the first of the occupants of the dwellings needed work done which required the earth rod to be installed

The DNO.

 

[ban-all-sheds]

Am I right in thinking that at the moment (under the 17th) it is prohibited to connect a local earth rod to the PME installation earth?

No.

 

[aesmith]

Earth rod(s) for the supply to the building, and make the equipotential zone the building as a whole, rather than having each individual flat as it's own EPZ.

If the block was on a PME/TNCS supply, then where does the network PEN split off into N and E for the customer, is there a central point within the building with N and E distributed to each flat, or does each flat have their own cut out?

 

[JohnW2]

I agree that everyone, even DNOs, have no choice but to 'accept' (and hopefully comply with) legislation once it is enacted. However, some interested parties (LFB?) seem to have extraordinarily powerful 'lobbying abilities', and thereby can strongly influence what legislation, or otehr regulations, does (or does not) get enacted - that's why I aid that amending ESQCR in the manner suggested might prove to be a very protracted purpose.