"Andrew Gabriel" wrote in message
...
In article ,
"G&M" writes:

"Andrew Gabriel" wrote in message
...

Where we are the PME earth is so
far above real earth you daren't trust it and have to convert back.

What sort of voltage difference are you talking about?
The supplier is required to ground the PEN (Protective earth and
neutral) conductor within some fairly short distance from your
house (like 60m, but can't recall for sure). Any significant
PEN to ground voltage would indicate a supply fault.

It is(was) about 45 volts, varying throughout the day. The earth is at
least half a mile away, I can see it dangling down the side of the pole
which feeds another farm first. Problem is when the last farm (of five)
on
the chain runs a heavy load the earth really moves.

There should be one where your service line joins the distributing
main. The 45 volts would also point to a fault. However, you can't
be losing 45 volts (and probably the same again from the phase
conductor) as you'd be pretty screwed if you only had 150V supply.
If it's just 45 Volts loss in the neutral and not the phase condutor,
that could point to a bad connection in the PEN which is very bad news.
If the 45 volts difference is being yanked towards a different phase
than yours, then the your mains voltage would be -cos(120º) x 45 =
23 volts higher than it should be, which should also be noticable.

You should report this as a fault to your distributor.
There's not enough info to tell what's wrong here -- it would be
interesting to know the three voltages L-N, L-real ground, N-real
ground, but don't try measuring these unless you are compitent at
working with mains voltages.


L-N is 251 volts. Drops slightly when the end farm is on load but not much.
L-N at the first farm is over the 253 volt limit but they don't want to
complain. L-N at the end farm can go as low as about 210 volts on load I
gather but they have been told tough.

N-real ground is typically 45 volts. It varies from 40 volts upwards but I
have never seen more than 50 volts. Do you think this still indicates a
problem at the PEN which as I say is about 3/4 mile away ?

Problem is the Peak Park Authority won't allow any more cables in the Park
and those we are using aren't really up to the task. Ideally the farms need
splitting into two groups with a separate transformer for each, and I am
sure United Utilities would do this if they were allowed. Remember the
prime goal of the Peak Park Authority is to turn the whole national park
into an unihabited tourist attraction.