How do multi switch light work?

Question

I'm talking about those light bulb sockets they install by almost all staircases. You flip the switch at the bottom of the stairs, the light turns on. You get to the top and flip the switch, it turns off. Is there a third box that accepts the signals from the other two that uses the truth table thingy to make it work?

Also, can someone explain to me what I need and how to install it?

Answer 1

When you have a three way switch with only two switch locations to control the light there are many different ways to wire it.  



       To make it work you need a hot wire at one end and a switch leg that goes up to the light at the other end.  Then you need to give your switch leg a neutral or white but don't count on colors it will mess you up in a lot of cases.

        So if you have a hot at one location put it on the black s***w or "common" and the other two screws will be the travelers which does not mater which s***w they are on.  if you have a hot and the switch leg in one location you need to send the hot or the switch leg.  If you send the hot than the switch leg will be your common. you may need to send your neutral from the hot location to the switch location to give the switch leg a neutral.  

      The travelers are two wires that go between the two switches and go on the gold screws in any fashion.  The important ones are the switch leg, hot, and neutral.  Hot at one end.  Switch at the other end.  Where are you getting your neutral.  

        Typical for around here is at one location having the switch and hot at the same location.  The black hot will be on the black s***w.  The white from that wire will be tied to the white from the switch leg and the black from the switched wire will be tied to the red wire (to send the switch to the other end).  The black and white will be used as travelers and the white will be colored black with a marker or tape.  

         At the other end the switch leg (red now) will be on the black s***w and and the black and white on the gold screws in any fashion.  should work.   All in all hot at one end switch at the other and where are you getting your neutral from.

         If you add another switch to the other two it gets even more complicated.  You would have a switch with four screws and two travelers on one side and two on the other and the wires need to stay together either black and white on one side and the other black and white on the other side. Sometimes it will be the two top screws and the two bottom screws depends on brand of switch.

          You may have the red sending a switch or hot through the box  so the red would be wire nutted together and not on the switch.  You also may be sending the neutral so then the white would be tied through and the red and black would be travelers.  Just hire an electrician to get it done safe.

Answer 2

I could go into great detail trying to explain this, but I will refer you to a website that will make it easy. http://www.rd.com/familyhandyman/content...

Try this and it should make sense.... if not hire an electrician to do it for you.

Answer 3

They use special sitches called 3 way switch. What you have is an extra wire between the switch boxes. How the switch works is when you turn it in one direction it sends power to the light. when you turn it in the other dirction it sends the power to the other switch.  The other switch operates the same.

Answer 4

Again, go to the library and find a book on it. or try your local hardware store.