Staircase wiring or multiway switching or two way light switch wiring is a commonly used connection to control a load from two different positions.That is from above or below the staircase, from by the side of the bed or door, indoor or outdoor. Staircase wiring helps to operate a lamp from two frequently using position. And also to, off the load after use if the load is a lamp or something that is used for only passage from one position to another.