Hi Attila

>In Sweden we have a low-budget electric distribution system using only four
>wires, with a common wire for both neutral and protective ground. We split
>the neutral and protective ground in the fuse-box in our houses. That
results >in a lot of parasit current in the protective ground, especially
when people, >not necessarily in the same building, use powerful
single-phase loads.

>My question is:

>Is Sweden the only country in Europe that don't use 5-wire transmission
>system, with separate ground and neutral wires ? I do work a lot with
>clearing those currents, especially for electrosensitive people, and I get
very >fed up with this ! Also, those automatic breakers (don't know the
english >word) that compare the current between the three phases and
neutral, and >triggers if there's a difference, keep trigging from those
parasite currents !

In Britain we always do things better :-)
You will find houses that are wired with no local earth, the Earth
connection being provided by the Electric Utility by earthing the Neutral at
the Substation.

Then you will find houses that are "properly" wired with a local earth
connection.

I have lived in houses wired to both standards and I can testify that the
PME system (no local earth) is Amateur Radio Hell. The only way round the
problem is to move to a house with a proper electrical system (that's what I
did) or provide a local earth yourself (if you are allowed by your local
regulations).

Before doing the latter, however, you should be aware that the safety of the
PME system requires that there be no local earth reference within the
building. In the event of a fault that results in a disconnection of the
Neutral Line between the Substation and the building, then all the electric
equipment in the building will rise to the line voltage (240volts in the
UK). This does not present a problem as the occupants of the building will
also be at 240 volts (Think of a bird sat an an overhead electric line).

However, if you have introduced a local earth and someone comes in contact
with both the local earth and electrical equipment whilst the fault
condition exists then as you say

>Pooh !

The person suffers from a condition known as "Terminated Living"  :-)

Regards

Chris

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