On Mon, 11 Dec 2017 23:05:08 +0000, The Other John wrote:

On Mon, 11 Dec 2017 22:08:42 +0100, D.M. Procida wrote:

Of course, when the light is switched off, you only feel the buzzing
when the plug is inserted in one orientation, because as well as being
unearthed, the sockets (here in the Netherlands) are unkeyed for
live/neutral...

When I worked in Amsterdam in 1979 I had reason to check mains wiring
and I found there was no 'live' and 'neutral', both wires were at 110
volts with respect to ground and 220 volts to each other, so I'm
surprised orientation makes a difference.

In that case, it doesn't. My late father was a Dutchman who hailed from
Rotterdam and I can remember him telling me about this domestic bi-phase
distribution set up with Dutch electricity supplies when I was in my
early teens. He was always bragging about how much more advanced Holland
was compared to the backward Brits, not only with regard to technical
stuff like this but also in the lack of imagination by the upper
management types in control of British industry who couldn't see beyond
the end of their noses when it came to making much needed and overdue
investment decisions to regain a competitive edge in the world market.

He had the situation pretty well sussed in my opinion but over the
years, I did start to wonder about the use of bi-phase mains supplies in
domestic house wiring. It's interesting to see this system mentioned for
the very first time in any usenet news group. Your experience goes back
to 1979 but do you know whether this was a national standard or only used
in specific regions or in housing schemes like blocks of flats?

The use of bi-phase supplies would certainly explain the absence of
polarised plugs and sockets since it wouldn't make any difference which
way round an appliance was plugged in. Also, all switches would need to
be double pole. A possible exception for double pole switching being the
use of two lighting circuits using 110v lamps with L-N supply shared
between the two lives. I believe that the filament lamps used in my
paternal grandparent's flat in Rotterdam were 110v types.

This would allow the use of higher efficacy 110v tungsten filament lamps
(a benefit of the American 117v system where, by sacrificing a little
more life to even higher efficacy, they choose a nominal 750 hour
lifetime rating over the more common 1000 hour rating of the UK's 240v GLS
lamps for domestic use which gave rise to the 60W 806Lm light bulb for
which we in the UK can offer thanks whenever we purchase a "60W" 810Lm
LED GLS lamp).

--
Johnny B Good