On Wed, 02 Sep 2015 14:39:26 +0100 (BST), "Dave Liquorice"
wrote:



If you ever wander out in the thr countryside and look at the 11 kV
power distribution it's all three wire, just the three phases.
It's not all 3 wire ,we had a two wire 11kV line over our fields which
served us and two other properties, in fact they were served first
when it arrived in 1960 ,as Dad had bought a new generator a few years
before and wanted to see some use out of it so we didn't connect till
1964. This branched off a 3 wire about 3/4 of a mile away, a similar 2
wire went in another direction but the two only shared one of the 3
wires in common so that was probably an attempt to keep the load
reasonably balanced.
They had to run another four poles to carry our 250V supply, each had
an earth connection to the neutral with a red metal plate on each pole
with PME in white letters on it, as a curious youngster I asked what
that meant so became aware of what a protective multiple earth was
when quite young.

With a
signle phase transformer one side will be connected to a real earth
connection at the pole, in our case it looks like a bit of 25 mm^2
before it disappears behind the protective capping and under ground.
This earth may or may not be carried on a seperate wire into the
house, around here the pole to house connection is mainly just two
wire, phase and neutral earth combined.

G.Harman