On Nov 21, 10:51*am, David Hansen
wrote:
On Thu, 20 Nov 2008 23:09:10 +0000 someone who may be Mike
wrote this:-

If one has a shed, garage or whatever it can be useful to turn
lights on/off from two or more locations.

If it's that far away you can't see the light then you're probably
breaking the rules regarding the equipotential zone.

Who said anything about not being able to see the light, of the
house presumably?

As for the wiring regulations and equipotential zones, they can be
complied with while still arranging switching from two or mo
relocations.

--
* David Hansen, Edinburgh
*I will *always* explain revoked encryption keys, unless RIP prevents me
*http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Sounds like an application for what over here is called (somewhat
oddly) a "3 way switch", although there are only two switches, such as
at the top and bottom of the stairs, to control a single light (or
several) for those stairs!

Maybe it's reference to the fact there are often three wires between
the two switches? Note 1.

In it's simplest form the live wire that is switched on and off by,
normally a single ON/OFF switch, is routed via both switches. Which
with the addition of that third wire allows one switch to be off and
the other to be on; alternately.

Both switches have to be of the CHANGEOVER type which usually cost a
little more (maybe 50cent to one dollar more each) than a regular ON/
OFF type.

Mounts in same wall box and requires a three conductor cable between
switches. The three conductor costs a little more than two conductor
(Including of course ground/earth). Thus, correctly wired, moving
either changeover switch to the other position causes light to go
either on or off. Have seen the same arrangement in UK homes.

In this Canadian house we use it for a staircase a bedroom passageway
and also for some outside lights that are not motion sensor operated.

There is also another option that involves the use of a third special
switch, (a switch that literally swaps over the two live wires going
through it) which is located between the other two, mentioned. That
allows a three switch (and I'm guessing one could have more than
three?) operation of one set of lights! If basic diagram needed please
email.

Cheers.