On 2 Sep, 20:44, John Rumm wrote:

Careful there - it sounds like the OP has what is intended to be a TN-S
supply where the earth is provided by the supplier. That last thing he
wants to do is start messing about providing his own earth connection
when that is the supplier's responsibility. It would also potentially
mean changing the whole installation to make it suitable for TT rather
than TN-S.


John,

Many thanks for your input - and thanks to all others for information
and comment.
My understanding is my present situation is an earthing through an
available pipe (the one containing the incoming supply), but that both
British Gas (boiler electrician) and DNO electrian are saying I need a
DNO-provided connection to the incoming cabling rather than being
earthed through the pipe. I assume that would then give me the TN-S
you refer to. They gave the impression it should be straightforward
and I just request it from DNO. My concerns are the vintage looks of
the DNO supply to the house and whether it's as straightforward as
that (much like the vintage gas supply pipes that have just been
replaced).

I take the point from others that an amateur can't easily accurately
measure the earth resistance at main connector or sockets. All the
cheap socket testers just seem to distinguish between some level of
earth and no earth and the more expensive (sok34) type only give three
levels of LCD display of qualitative earthing effectiveness.

I've contacted the DNO again to try and speed up the initial
assessment - I think they should be the first option. I'm in a
residential area of a large city but mainly older property (1930s)
and, understandably, the public supply water, gas and electricity
pipes/cables are/were somewhat elderly. I can't be the only one who
has needed new earthing and I'm hoping DNO provide a viable solution.
Otherwise, if I understand the electrician, I think some sort of front-
end RCD to the whole system was what he was suggesting as a possible
option.

Thanks again

Regards,

Toom