Re: electrical deaths

Carlos E.R. <robin_listas@es.invalid> wrote:


 [...]

My neighbour has a new led fixture above the street door, flood type.
When it is off, it still has some light. I guess the switch is on the
neutral, and there is a small leak.

If the live and neutral run directly to the fitting and there is a long
branch of cable running to the switch, it could be caused by capacitive
coupling between the wires in the switch branch.

In modern UK practice (probably harmonised across Europe) there has to
be an earth conductor in all fixed wiring.  This is usually located
between the two power conductors and acts as a screen against capacitive
coupling - but very old wiring doesn't have it and, even if it is
present, it may not have actually been connected to earth.

Multi-core wiring, which would be used with a two-switch system, only
has the earth between two of the three conductors, so there is still
capacitive coupling between the other two.


--
~ Liz Tuddenham ~
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