High earth reading

[sparkwright]

On a TNS system, shouldn't the DNO provide either a clamp on the sheath, or an earth block?
It doesn't seem right that non-DNO should be tightening things onto the sheath of their cable.
They seem confident that the BS591 clamp is not there, and that NEVER those.
On those ancient cables, you only ever see an ancient clamp, or a cable sweated on, or a modern BS591 clamp that an electrician has fitted.
It must be a regular occurrence having a BS591 clamp, so I don't know why it's such an ordeal for the DNO to fit one of theirs whilst investigating the fault.

 

[JohnW2]

On a TNS system, shouldn't the DNO provide either a clamp on the sheath, or an earth block?

Indeed - but, as discussed, if they have never regarded it as TN-S (i.e. regard it as TT), then they obvoously would never have done that.

It doesn't seem right that non-DNO should be tightening things onto the sheath of their cable.

Indeed not - but it's quite possible (and presumably far from unknown) for a non-DNO person to attempt to derive a TN-S earth from what the DNO regards as a TT supply.

It must be a regular occurrence having a BS591 clamp, so I don't know why it's such an ordeal for the DNO to fit one of theirs whilst investigating the fault.

As above,, my suspicion has been from the start that, since it's the sort of clamp that the DNO would not use, the DNO believe that they have never provided any sort of earth, and therefore are under no obligation to provide or 'maintain' one now.

 

[morqthana]

my local railway is not government owned, in the main run by volunteers, we are a bit old-fashioned where I live, we still have steam trains.

Your "local railway" is a nostalgia tourist attraction, not part of a public transport system.