PME and Amateur Radio
As there seems to be a few mis-conceptions about RCD devices and PME, I
thought the following diagram might help.
In the event of a Neutral conductor failure, domestic load current
from your property and and (possibly neighbour's) consisting of several
10's or 100's of amps will still return to the sub-station transformer
via the Electricity Co.'s bonding Neutral-Earth at the distribution point.
The earth connection obviously has some impedance, so the current flowing
through it raises point A by V=I*R volts. So now our mains earth is floating
at "V" volts above the general mass of the earth.
In our shack this means our nice shiny radio chassis is at V volts above
real earth. But outside we have an aerial with a ground connection, feeding
into the shack, by, say, co-ax. The braid of this co-ax is at real earth
potential which is currently below our mains earth. If I now undo this
co-ax lead from the rig, I am holding in one hand "real" earth (co-ax),
and in the other mains earth, which is higher, therefore current flows
It doesn't take much to see that this electrocution current has flowed
through my RCD in both directions, so it is still balanced and has no reason