"David Hansen" wrote in message
...
On Sun, 14 Jan 2007 14:19:48 GMT someone who may be "Julian"
wrote this:-

AIUI mains voltage is now 230 volts -6% +10%. ie 216 to 253 - correct or
rubbish?

My question is how is it measured? [snip] So, under what load condition is
the
voltage measured?

A nominal supply voltage of 230V does not mean that the supply will
be at precisely 230V all the time. It means that it should be within
the specified tolerances at all times, other than when there is a
fault.

The precise voltage at your terminals at any particular time will
vary according to the load on the system (the load from you and
other customers in the area) and what the automatic voltage
regulation system is doing. It will be higher on no-load and will
reduce as load is applied, because it is (partly) a function of the
impedance of the external system. The same is true on your wiring.

Your voltage regulation doesn't sound particularly good. How many km
of 11kV route is there before it gets to the pole your photograph
shows? It is certainly worth repeating these measurements and then
having a gentle word with the technical people of your supplier,
which may take persistence on your part. It may well be that a high
resistance has developed somewhere on the external system.



It may be an idea to obtain a "Loop Tester" this device can be used to
messure the effective resistance of the supply. The supply company or any
electrican will be able to do this. Also measure the voltage between N and E
when you have a high load.