Re: Three way switch for kitchen
You might also consider a wireless remote switch. The main unit is a direct replacement for the existing switch, and you have a wireless transmitter that you can place anywhere else in the house. It's a quick, easy way to overcome the mysteries of the 3-way switch. Nevertheless, I'll try to explain how I would do it, and hopefully not add confusion.
In this example, I will assume that you can run a 14/3 (15A circuit) or 12/3 (20A circuit) wire from the existing switchbox. Similar to JLMcDaniel's diagram. My method works whether you have one or two cables coming into the switchbox. Switch "A" is at the existing location; switch "B" is at the new location.
First, the only existing wires you will work with are the ones that connect directly to the existing switch. You shouldn't need to mess with the other wires in the box.
Connect one of the two existing wires to the dark-colored screw of switch "A". Connect the black wire of the new cable to the other existing wire at switch "A". Connect the remaining two wires (red & white) to the remaining screws -- it doesn't matter which to which.
Now at switch "B" connect the black wire of the new cable to the dark-colored screw on the switch. Connect the red & white to the other screws.
As others have mentioned, mark the new white wire with black or permanent marker. This is necessary to make it clear to future "electricians" that it's not a neutral. (In electrical wiring, white always indicates neutral and green always indicates ground. It seems like gray might mean something, too, but I don't remember. All other colors may be used for everything else and should not be used for neutral or ground.)
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.