In message ,
wrote:

In uk.d-i-y, Jim Michaels wrote:


If you are at all concerned about EMF you should start by eliminating
all rings in the house wiring.

Really. Well well. Fascinating what one learns on Usenet these days.

Maybe you can explain to us all how it is that a circuit - ring, star,
or crop-circle ompholotic spiral - in which the currents 'out' and 'back'
pass in opposite directions in conductors sharing the same outer jacket -
gives rise to an Electro-Magnetik Feeled?

Not wanting to contradict you too much (don't want to say too much
against the magic force as I earn my living from it), but this is only
the case if the currents and their paths are precicely balanced. In a
radial the current (except under certain fault conditions) will be
balanced, but in a ring, the slightest difference in impedance between
the two halves of the "live" ring and the two halves of the "neutral"
ring could quite easily lead to (miniscule levels of) unbalance.

The fact that the cables are side-by-side, separated by at least 1 cable
diameter doesn't help either. If they were twisted (as in flex or
telephone or computer CAT5) the radiation problem would be lessened
further, and coaxial cables - as generally used by the power companies
for the last leg to your house these days - are the best of the lot,
especially in a PME arrangement when the outer (neutral) is pretty
firmly grounded. I'd expect to see very little field from such a wire.

Not that I'm an expert in EM fields, but I do have a background in audio
where all the above measures (balancing, twisting, coaxial) are put to
incredibly good effect in reducing problems from both radiated and
induced radiation.

Good point about the lighting circuits - there was a discussion here
very recently about that IIRC, and in particular with reference to
hearing aid induction loop coils.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
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