Wiring of Two Way Light points are now common for Electrical Installation Work. Here we are considering wiring a Two Way Light point for 50Hz, 230V AC Power Supply. Installation work described here is according to British Standards [ IEE Regulations and Practice ].
For Industrial applications, 1.5 mm2 [called as 1.5 mm squared] Cross sectioned double insulated Cu [Copper] Cables [Cu/PVC/PVC] are used for the Phase [Live ] and the Neutral cables.
For Residential applications, 1.0 mm2 Cross sectioned double insulated Cu [Copper] Cables [Cu/PVC/PVC] are commonly used for the Phase and the Neutral cables.
Earth [Ground ]cable should be 2.5mm2 single insulated Cu[Copper] Cables [Cu/PVC] for both Industrial or Residential type of applications.
Cable lengths for the above circuits will be such that voltage drop along the cables will be with in the approved limits of 10% of Supply Voltage.
PVC Boxes to install the 2 Way Light Switches-02 nos
One Gang 2 Way Light Switches-02 nos
PVC Ceiling Rose [3 terminal type] -01 nos
Lamp Holder-01 nos
MCB 6A -01 nos [ from a Distribution Board already installed]
Install the switch boxes at the two required positions.For example you may need to operate the room light from a switch near the door and then from a switch by your bed side.Then install the Ceiling rose where the Light should be. Lay PVC conduits from the Distribution Board and interconnect to the Switch positions and the Ceiling Rose position. The conduits can be embedded into the wall structure and or lay outside, clipped to the wall or structure. Instead of PVC conduits and switch boxes, GI conduits and switch boxes are being used for Industrial type of installations where you need protection for cables from physical damage. In some wooden structured buildings, the cables are installed inside panels without conduits being used.The Cables should be colour coded correctly for Phase[Live],Neutral and Earth.
The Two way switch has three terminals out of which one is a common terminal.
Method of Wiring -Residential
Make sure that the Power is isolated [ shut down] to the Distribution board or any circuit you will be working with.
Connect the Phase [L] wire to the outgoing side of a 6A or a 10A [Maximum] MCB from the Distribution Board [DB]. Draw the Phase wire to the nearest Switch box and connect to the common terminal of the first Two way switch.
Connect two separate phase wires to the remaining terminals of the first 2 Way switch and draw them to the other Switch box position and connect to two separate terminals of the second 2 Way switch.
Connect the common terminal of the second 2 Way switch to a Phase wire and draw that wire to the Ceiling rose.
Now connect a Neutral [N] wire to the Neutral Link provided in the DB and draw it to the Ceiling rose.
It is good practice to number the Phase and the Neutral wires at the DB for easy identification as one circuit.
Connect the Earth [E] wire to the Earth link provided in the Distribution Board. Draw these Neutral and Earth wires directly to the ceiling rose and use the two spare terminals to connect these wires separately. Now all the 3 terminals of the Ceiling rose are connected.
Take the lamp holder and a short length of 3 core flexible cable and connect the Phase and Neutral wires to the holder. If the holder is a pin type one , then either the Phase or the Neutral can be connected to any terminal. If the holder is Screw type, then the Neutral should be connected to the threaded part of the terminal and the Phase to the other terminal. Normally the Earth wire is used for a Lamp fitting with metal parts to be connected.
Then connect the Phase, Neutral and Earth wires of the flexible wire of the Lamp holder to the Ceiling rose to correspond to the L,N and E respectively.