2 Way Switching
2 way switching means having 2 or more switches in different locations to control one circuit. They are wired so that operation of either switch will control the light(s).
To achieve 2 way control the usual single switch is replaced with either of the following circuits:
a ------o------------------------------------o L1
/
O----------------------------------------O COM
/
b ------o------------------------------------o L2
switch cable run switch
Alternative method of 2 Way Switching:
o------------------------------------o L1
/
a ----O O----- b COM
/
o------------------------------------o L2
switch cable run switch
3 Way Switching:
a ------o---------------o o----------------o L1
/ \ /
O------------------ X ------------------O COM (no connection at X)
/ \ /
b ------o---------------o o----------------o L2
switch cable crossover sw cable switch
Alternative method of 3 Way Switching:
o---------------o o----------------o L1
/ \ /
a ----O X O----- b COM
/ \ /
o---------------o o----------------o L2
switch cable crossover sw cable switch
- a & b are the 2 connections that are used in place of the usual single switch (i.e. one connected to live, and the other is the switched live return to the ceiling rose or lamp fitting)
- the switches at each end are 1 pole 2 way switches
- Any number of crossover switches may be added to give 3 or more way switching.
- the cable runs are from one switch location to another
- 3 core & earth cable is usually used for 2 way switch circuits.
Notes:
The first example given in each case is the preferred connection method. This is also least likely to cause interference problems when installed in building that have an inductive hearing loop system.
The alternative circuits may appear to require one less wire, however in reality is is usually necessary to return the COM connection at the second switch position to the first switch or the rose or light fitting which typically needs a wire. They are included here as they are often encountered in older wiring.