On Wed, 29 Jun 2005 09:15:42 +0100, "Dave Plowman (News)"
wrote:

In article ,
Dave wrote:
I have a puzzle with the wiring of the hall/landing lights in a house I
have just moved into.

The hall/landing has three light switches, one ouside the bathroom, one
at the other end of the landing outside the bedroom and one besides the
front door.

If I switch the lights on using the bathroom switch then try and switch
the lights out at the bedroom they don't go out, they just flicker as
the switch is operated.

If I go down stairs and attempt to switch them off at the front door,
same thing happens, lights stay on just flicker as switch is operated.

If I now go back upstairs nether switch will work so I can't switch the
lights off. I have to go back downstairs and reverse the front door
switch before the bathroom switch will again switch the lights off.

There are further combinations, but I am confused enough already.

Sounds like you've got a faulty switch. You could remove them one by one
and test with a DVM.

There are two types of switch in a three way switched circuit - 2 x 2-way
at the ends of the circuit and an intermediate in the 'middle'.

If you know the circuit once worked properly, then a wiring fault is
probably ruled out, so if you haven't got a DVM then buy one new two-way
switch (the cheapest) and try and sort the fault by substitution. If this
doesn't fix it then it's likely the intermediate.

I've included the circuit below for reference.



L1 L1
0===========0 0===========0============= Line
| \ / |
C 0================================O C
\ / \ /
0===========0 0===========0============= Switch return
L2 Optional L2
Intermediate
Thanks

Fault found to be incorrectly wired landing switch