In article , (Doug Miller) wrote:
In article .com,
wrote:
The foyer in my house has two lights about 1/4 away from each end, and
there are two switches at either end. Something like the following:

Switch A Light 1 Light 2 Switch B

Switches A & B control lights 1 & 2 in the following way:

Switch position Result Comment
A_up, B_up Both lights on == lights 1 & 2 are in parallel
A_down, B_up Both lights off As expected
A_up, B_down Both lights off As expected
A_down, B_down Both lights OFF THIS IS THE PROBLEM

So, in effect, switch A is behaving as a master switch: if A is down, the
lights are off regardless of what happens at B, and if A is up, then the
lights are controlled by B.

Hmmm.... I posted a bit too soon. They're *both* acting this way, aren't they?
If B is down, they're off regardless of what happens at A, and if B is up then
they're controlled by A.

*IS* switch A in fact a three-way switch?

Or, for that matter, is B?

You'll see these symptoms if either one is a standard on-off switch. Or both.

It is the 4th case (A_down, B_Down) that is baffling me. In a regular
3-way switch, the lights should come on. In effect, my 3-way switch
behaves like a "2.5-way switch, so to say". I would greatly appreciate
your advice and suggestions on the following.

Q1. Does this indicate a problem at Switch A? Or Switch B? Both?

If the switches have *always* worked like this, I'd certainly be looking at
switch A first. It most likely indicates that switch A is mis-wired: if the
wire that should be connected to the common terminal is connected to one of
the traveler terminals instead, it would produce *exactly* the symptoms you
describe.

Having *both* switches mis-wired would *also* produce those symptoms. If
*only* switch B is mis-wired, you'd see the same problem, but B would be the
"master switch" instead of A.

Oops, spoke too soon again... Symptoms could mean either switch mis-wired, or
both of them. Assuming they're both 3-ways - which they might not be.

Or, switch A might be a conventional two-way switch. (If it is, have a look
at switch B - it might be, also.) If that's the case, you might not even have
the three-wire cable needed for three-way switch operation, and it might be
time to call an electrician.

Even if A is a 3-way, look at B - symptoms could be accounted for by a
properly wired 3-way at A, and a standard on-off at B.

If the switches *used* to work as proper three-ways, there are several
possible explanations:

1) One of the switches is defective. Try replacing one; if that doesn't solve
the problem, replace the other one with the one you just replaced.

2) One of the traveler wires is disconnected at one switch or the other, maybe
both - so check both.

3) The 3-wire cable between the switches does not necessarily run from switch
A directly to switch B. It might be spliced at one of the light fixtures, and
one of the splices for the traveler wires has come undone.

4) It's unlikely, but still possible, that one of the traveler wires is broken
somewhere inside the wall or ceiling. The only way to fix that is to pull new
cable.

Q2. Can this be rectified by opening the switch boxes?

Maybe. Depends on what the problem is - but you have to open at least one of
the boxes to find out, maybe both, and maybe both light fixtures as well.

Q3. I have a tester and have done the following electrical work in the
past, without any problems: replace house fuse; replace the outlet box
for the 200 V (dryer); extend the power line and add a motion detector
light to the outside of the garage. Should I attempt to rectify the
3-way switch myself, or should I pay an electrician? (Seems silly to
pay $75, minimum for the visit, to rectify such a simple problem).

Sounds like you should be able to handle it yourself.


--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?