Farm earthing arrangements.

I've seen that DNOs can have rather poor detail about parts of their network, and I realise that they've inherited the network, moved to computers, etc.  But I'd have thought there'd be occasional inspection (10yr?) to check the basics at LV transformers, e.g. soundness of main electrode, wire to it, pole, etc., which would be the opportunity to check that there's a record and that it fits the fact.  Do they have a chosen policy or obligation of checking through the system, or is it only a reactive service after complaints?


Regarding PNB vs PME vs etc:  one could go on forever ... so I won't get into several of the aspects that tempt me - e.g. about mutual exclusivity or not, of PNB/PME. But I will just observe (not relevant to the WPD system in the OP, but to mapj1's point)  that I find it a strange idea to consider a system with a combined N+E downstream of the nearest-to-source earth electrode to be other than PME, even if it's deemed PNB by virtue of some distance from the source to that earth.  Even if the supplier has only the one electrode, then as soon as they've provided an "earthing terminal" to this combined N+E at an intake,  that customer could then or later end up bonding it to things that in effect are good electrodes. The broken-conductor shock-danger aspect of this multiple earthing of an active conductor is what mapj1 mentioned. And even without a break, farm animals outside a very well bonded area may be upset by small voltages.  I'd want complete separation of N+E for all points downstream of the first earthing, in order not to consider PME 'issues' to be relevant. (When did they stop having to get the home secretary's or suchlike's permission for more than one earth on a neutral? Some countries have been very fussy about this: for Germany I've heard the power companies felt very unfortunate for having come after the telephone/telegraph ones, which then complained about any earth currents. I think that was the main concern with getting permissions in the early days of PME.)

I've seen that DNOs can have rather poor detail about parts of their network, and I realise that they've inherited the network, moved to computers, etc.  But I'd have thought there'd be occasional inspection (10yr?) to check the basics at LV transformers, e.g. soundness of main electrode, wire to it, pole, etc., which would be the opportunity to check that there's a record and that it fits the fact.  Do they have a chosen policy or obligation of checking through the system, or is it only a reactive service after complaints?


Regarding PNB vs PME vs etc:  one could go on forever ... so I won't get into several of the aspects that tempt me - e.g. about mutual exclusivity or not, of PNB/PME. But I will just observe (not relevant to the WPD system in the OP, but to mapj1's point)  that I find it a strange idea to consider a system with a combined N+E downstream of the nearest-to-source earth electrode to be other than PME, even if it's deemed PNB by virtue of some distance from the source to that earth.  Even if the supplier has only the one electrode, then as soon as they've provided an "earthing terminal" to this combined N+E at an intake,  that customer could then or later end up bonding it to things that in effect are good electrodes. The broken-conductor shock-danger aspect of this multiple earthing of an active conductor is what mapj1 mentioned. And even without a break, farm animals outside a very well bonded area may be upset by small voltages.  I'd want complete separation of N+E for all points downstream of the first earthing, in order not to consider PME 'issues' to be relevant. (When did they stop having to get the home secretary's or suchlike's permission for more than one earth on a neutral? Some countries have been very fussy about this: for Germany I've heard the power companies felt very unfortunate for having come after the telephone/telegraph ones, which then complained about any earth currents. I think that was the main concern with getting permissions in the early days of PME.)