It must be remembered that the rules (and supply arrangements) are different
between countries, and the UK requirements when you take PME (Protective
Multiple Earthing) into account can give problems with external grounds.
Especially if the RF ground and the mains ground are only connected by the lead
to the equipment - in this case, a ruptured neutral can cause major problems,
like burning the house down! In my case, the neutral is connected to a ground
rod at base of the electricity pole in the garden, the 'safety ground' for the
house is a ground rod by the front door, and the RF grounds are rods around the
tower and the mast for the VHF antennas. As a result, my RF grounds are lower
resistance than the safety ground, and I don't have the problem of the
possibility of a ruptured neutral causing problems.
The comments about not using the ground lead as a current return apply
universally, though. Some of the older ARRL handbooks have designs which do,
though. I always work on the basis that the neutral should be considered as
'live' conductor, even though it is at or near ground potential. Then I use
double pole switches to switch live and neutral, and fuse the live side only.
73
Peter G3RZP
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