A double-pole switch allows you to control two separate circuits using the same switch, while a three-way switch allows you to control a single circuit from two different locations. A double-pole three-way switch is able to integrate both of these functions into one. With this switch, you will be able to control two separate circuits from two different locations, for example, being able to simultaneously turn on a light and a fan from next to the door you would use to enter a room, and then turn them off at the same time with the same type of switch next to the door where you exit the room. These types of switches may be used to control 240-volt circuits.
Prepare two cables, each with three wires inside: the live wire, the ground wire and the neutral. From each cable, connect the three wires to their respective terminals on the circuit breaker panel. The terminals on the panel are usually marked and can easily be identified. Prepare two other cables, each with two wires inside, by replacing the exposed portion of insulation of the neutral wires with insulation that is of the same colour as the live. The live wire is normally characterised by red or brown insulation.
Screw the two live wires from the two cables originating from the circuit breaker panel onto the two input terminals on the first switch, noting the label on the terminals. The switch has two terminals on one side and four corresponding terminals on the other; for each input terminal, there are two output terminals on the switch. Connect the two cables with only two wires inside to the other four terminals on the other side of the switch, each cable's two wires connected to adjacent terminals. Each of the two cables should represent a different circuit.
Connect the same two cables with two wires inside to the four terminals on the second switch, ensuring that each wire ends up joined to a terminal labelled exactly the same as on the first switch.
Connect the live wires of two more cables, each with three wires inside, to the two terminals on the other side of the second switch, paying careful attention to the labels. Connect the two neutral wires of these two cables to the neutral wires from the first two cables from the circuit breaker panel using wire connectors. The neutral wires thus will run straight through to the appliance or light being controlled by the switches. Make sure the neutral wires are joined together with respect to their different circuits. Connect the ground wires to the ground terminals of the switches.
Connect two bulbs or devices to the end of the second pair of three-wire cables, each to a different circuit, and test the connections to see whether they are working properly.