A 3-way switch allows lighting to be turned on or off from two separate locations. It uses three conductors to connect two SPDT switches to a light fixture or bulb. The light will be off when both switches are in the same position (both position 1 or both position 2) and on when the switches are in opposite positions, with one in position 1 and the other in position 2 or vice versa.

1. LIGHTING CONTROLS
3-WAY SWITCH

2. 3-WAY SWITCH
It is a lighting control that can turn “off” or turn
“on” a lighting fixture in two different
locations. It is called a 3-way switch because
there are 3 conductors connecting the
switches.

3. 3-WAY SWITCH MATERIALS
2 Pcs SPDT switch
1 lamp holder/outlet
1 lighting fixture/bulb
Wires
2 Pcs Utility Box

4. 3-WAY SWITCH DIAGRAM
SPDT SWITCH A SPDT SWITCH B
Live Side Lighting Bulb
Return Line
Conductor

5. 3-WAY SWITCH OPERATION
• The operation of a 3-way switch is very simple:
When the two switches are in the same
position –both in position 1 or both in position 2
– the bulb is “off”.
When the two switches are in opposite or
unlike positions – switch A in position 1 and
switch B in position 2 ; or switch A in position 2
and switch B in position 1 – the bulb will turn
“on”.

6. SWITCH POSITIONS
Position 1 Position 2

7. Sw A in position 1; Sw B in position 1
Bulb is “Off”

8. SW A in position 2; Sw B in position 2
Bulb is “Off”

9. Sw A in position 1; Sw B in position 2
Bulb is “On”

10. Sw A in position 2; Sw B in position
Bulb is “On”

11. Circuit Realization

12. CIRCUIT REALIZATION