multiway switching

Multiway switching is done using special switches that have additional contacts.

Most electricians know these simple guidelines when wiring multiway switching.

Such switches can also be used as intermediate switches in a multiway switching system for control of lamps by more than two switches.

For example, multiway switching is useful for corridors and stairwells so that a light can be turned on and off from two locations.

In multiway switching, the correspondence between a single switch's state and whether lights are on or off depends on other switches in the circuit.

In building wiring, multiway switching is the interconnection of two or more electrical switches to control an electrical load (often, but not always, lighting) from more than one location.

By use of multiple-pole switches, multiway switching control of a lamp can be obtained from two or more places, such as the ends of a corridor or stairwell.

The controlled load is often a lamp, but multiway switching is used to control other electrical loads, such as an electrical outlet, fans, pumps, heaters, or other appliances.

Unless the doors are adjacent, a light switch is required near each door, wired either for multiway switching or, if the switches are on the outside of each door, in parallel.

While a "normal" light switch needs to be only a single pole, single throw (SPST) switch, multiway switching requires the use of switches that have one or more additional contacts and two or more wires must be run between the switches.