Wiring of a Light point is the most common out of all Electrical Installation Work. Here we are considering wiring a 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 Box to install the Light Switch-01 nos
One Gang Light Switch-01 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 box at the required position.Then install the Ceiling rose where the Light should be. Lay 1/2" PVC conduit from the Distribution Board to the Switch position and from the Switch to the Ceiling Rose. 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.
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 Switch box and connect to one terminal.
Connect another Phase wire to the remaining terminal of the switch and draw it to the Ceiling Rose position and connect to one of the 3 terminals of the Ceiling rose.
Connect the Neutral [N] wire to the Neutral Link provided in the DB.
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.