In article .com, " wrote:
OK, I think I understand your diagram... the labels "Grey front", "Back
Black", etc. refer to the colors and locations of *cables* in the boxes,
right? (Each cable containing several wires)
Right, "grey" and "black" refer to the color of the insulation of the
cables.

Gotcha.

For what it's worth, it's vanishingly unlikely that *any* of the cables in the
box containing the GFCI and dimmer has its other end in the box containing the
4-way switch. When controlling a light from 'n' locations, you need two 3-way
switches and (n - 2) 4-way switches; e.g. for 2 locations, two 3-ways and zero
4-ways; for 3 locations, two 3-ways and one 4-way; etc. -- and the 4-ways
*always* sit in the middle, with the 3-ways at the ends. Power goes to one
3-way, and the light is connected to the other. Since the power for the island
lights is clearly routed through the GFCI, there must be a cable leaving that
box and going to one of the 3-way switches -- *not* the 4-way.

What I don't understand, though, is how this works at all.
It might help to know that the dimmer was added during a recent kitchen
upgrade (~2 years ago).

Sorry, I guess I wasn't clear -- your diagram does not appear to represent an
electrical circuit that can actually function. Maybe I'm misunderstanding or
misinterpreting it. Or maybe there's a mistake in it -- have you
double-checked it to be sure it accurately represents the reality of what's in
the box? (Referring specifically to the diagram of the GFCI & dimmer wiring)

The answer to one question might help: I understand you can't turn the island
lights on without turning on the recessed lights too.
What about the other way around -- can you
turn on the recessed lights without also turning on the island lights?

Yes, the recessed lights turn on regardless of whether the island
lights are on or off.

Interesting. And somewhat surprising.

Do you have a voltmeter? That could prove invaluable in tracking down which
wires go where.

Yes, I have a voltmeter. I'd be more than happy to measure the voltages
under the various configurations (switches on/ off), but there are a
LOT of combinations. Would really appreciate some focused advice on
what to measure.

We're getting there... I still don't have all my ducks in a row yet.

- I plugged a light into the GFCI outlet, and pressed the "test"
button. The GFCI tripped as expected, and the light went out.
Which light? The LED in the GFCI, or one of the room lights?

To test the GFCI, I plugged a small night light into the outlet. When I
pressed "test", the GFCI tripped, and the nightlight went out. The LED
on the GFCI came on. Pressing reset re-enabled the circuit (LED out,
nightlight on). Note that if the GFCI trips, the island lights also go
out.

What about the recessed can lights? Do they also go out when the GFCI trips?

Does anything *else* go off when the GFCI trips? Any outlets that go dead?

(I'm betting on 'yes' answers to all of the above)

[snip]

With the switch for the island lights being in a separate box from the switch
for the dimmer, it's hard -- but not impossible -- to imagine how that might
have become goofed up by changing only the switch.

Right. My guess is that the electrician (who appeared to be quite
competent, he seemed to know what he was doing) did something creative
to add in the dimmer switch.

"Creative" and "electricity" is not usually a good combination. ;-)

Also, the outlet was originally a regular
outlet, not a GFCI. He replaced it with a GFCI to bring it up to code
(the outlet is over a countertop, GFCI is sort of unnecessary since the
sink is in the island, but code is code).

That shouldn't matter, I don't think.

Any advice on what to do next?

Just double-check your diagram, and answer Round Two of my questions... I'll
be back atcha later on when I see your answers. Interesting little problem...


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

It's time to throw all their damned tea in the harbor again.