Adding a New Light and Switch - Two Way

This article explains how to install two way lighting so that one light may be operated from two different light switches.

Rigging up the light and the ceiling rose, connecting to the lighting circuit, and connecting the primary switch is all carried out in much the same way as for one way lighting.

Two way lighting diagram – earth conductors not shown

The difference between two way and one way is basically down to the switches and the link cable between them. The cable used for this link has an additional conductor. We use suitably sized three core and earth. The switches used will have two 'ways' and therefore three terminals each.

Switch off the power at the consumer unit for the circuit from which you are going to take the supply for the new light. If you have removable fuses at your consumer unit, switch off the power at the consumer unit and remove the fuse for this circuit.

Examine the cabling and identify the system which has been used. This may be a junction box circuit, or loop type circuit, or a combination of the two. For more information on this see our Lighting Circuits Guide.

If the wiring has no earth conductor, the services of a professional should be sought.

Locating the light

Drilling a hole through the ceiling for the new lighting point

1. Decide upon the location for the new light and make a hole in the ceiling large enough to accommodate the cable(s). If possible, choose a position which enables the new ceiling rose to be screwed directly to a joist.

Wooden batten to support light fitting

2. Otherwise, mount a wooden batten between the two nearest joists to provide the fixing.

Locating the two switches

Positioning the new switch

3. Decide where you want each of the switches for this light.

4. Check that there are no cables, pipes etc buried below the surface.

Mounting the light switch back box

5. Cut out the wall to mount the switch box in the same way as for mounting socket boxes.You may use a Surface Mounted Box, a Flush Mounted Metal Box, or a Flush Mounted Plasterboard Box.

Primary switch

Switch cable being fed through to switch position

6. Feed a suitable two core and earth cable (see Lighting Circuits for details) from the position of the new light through to the switch. We will refer to this as the switch cable.

Link cable being fed through to light switch

7. Feed a suitable three core and earth cable through from the secondary switch position to this box as well. We will refer to this as the link cable.

Removing the cable entry blanking piece

8. Remove a cable entry blanking piece from one of the switch box sides. If you are mounting the switch in a solid wall, you will have used a metal box and will need to line the cable entry point with a rubber grommet.

Switch back box being positioned

9. Feed the cables through, then secure the back box to the wall.

Cutting outer sheath with side cutters

10. Strip and prepare the conductors of both cables ready for connection. Cut through the end of the outer sheath of each cable carefully using a pair of side cutters. Be sure not to cut into the insulation of the conductors.

Cutting sheath with earth conductor

11. Peel back the sheath of each cable to reveal the conductors and grip the end of the bare earth conductor with a pair of pliers. Draw the wire back through the sheath like a cheese wire.

Cutting excess sheath with side cutters

12. Fold the excess back on each and trim with the side cutters.

Stripping insulation from conductor

13. Separate the conductors and trim the insulation of each back by about 1/2" with wire strippers. For detailed information on this see our Cable Stripping Guide.

Insulating bare earth conductor with sleeving

14. Insulate the earth conductors with green and yellow sleeving. This should be cut to length and fed over the conductor so that about 1/2" is left exposed at the end to match the other conductors.

Tagging the conductors with brown sleeving

15. Tag the blue of the switch cable, and the black and the grey of the link cable, with brown sleeving. This serves to identify that all of these are live conductors.

Connecting the brown of the link cable

16. Connect the brown of the link cable to the terminal labelled ‘C’ or ‘Common’

Connecting the black of the link cable and blue of the switch cable

17. Connect the black of the link cable and the blue of the switch cable to the terminal labelled ‘L1’

Connecting the grey of the link cable and brown of the switch cable

18. Connect the grey of the link cable and the brown of the switch cable to the terminal labelled ‘L2’

Earth Connection

19. What happens with the sleeved earth conductor depends upon the fittings being used.

  • Plastic switch and plastic mounting box - the earth conductor is connected to the earth terminal on the back of the mounting box if there is one. Otherwise it is secured in a plastic terminal connector block and tucked safely out of the way. In this situation some people trim the earth right back but this should not be done. If someone wants to fit a metal switch at a later date the earth will be too short.
  • Plastic switch and metal back box – the earth conductor is connected to the earth terminal on the back of the metal mounting box.
  • Metal switch and plastic back box – the earth conductor is connected to the terminal on the switch marked with the earth symbol.
  • Metal switch with metal back box - the earth conductor is connected to the terminal on the switch marked with the earth symbol. An earth tail is also connected between here and the earth terminal on the back of the metal mounting box.
Easing the switch back to the wall

20. Double check your connections and ease the switch back to the wall folding the cable carefully into the box.

Securing and aligning the switch

21. Secure the switch with its fixing screws ensuring that it is level

Secondary switch

22. Remove a cable entry blanking piece from one of the switch box sides. If you are mounting the switch in a solid wall, you will have used a metal box and will need to line the cable entry point with a rubber grommet.

Feeding the link cable into the switch box

23. Feed the link cable coming from the primary socket through, then secure the back box to the wall.

Cutting outer sheath with side cutters

24. Strip and prepare the conductors ready for connection as before. Cut through the end of the outer sheath carefully using a pair of side cutters. Be sure not to cut into the insulation of the conductors.

Using earth wire to cut outer sheath

25. Peel back the sheath to reveal the conductors and grip the end of the bare earth conductor with a pair of pliers. Draw the wire back through the sheath like a cheese wire.

Trimming excess outer sheath with cutters

26. Fold the excess back and trim with the side cutters.

Trimming conductor insulation

27. Separate the conductors and trim the insulation of each back by about 1/2" with wire strippers.

Sleeving earth conductor

28. Insulate the earth conductor with green and yellow sleeving. This should be cut to length and fed over the conductor so that about 1/2" is left exposed at the end to match the other conductors.

Tagging conductors with sleeving

29.Tag the black and the grey of the link cable with brown sleeving. This serves to identify that these are live conductors.

Connecting the brown conductor

30. Connect the brown to the terminal labelled ‘C’ or ‘Common’.

Connecting the black conductor

31. Connect the black to the terminal labelled ‘L1’.

Connecting the grey conductor

32. Connect the grey to the terminal labelled ‘L2’.

Connecting the sleeved earth conductor

33. Connect the green and yellow sleeved earth. The way this is done depends on the set up you have - as detailed above for the primary switch.

34. Double check your connections and ease the switch back to the wall folding the cable carefully into the box.

Securing and levelling the switch

35. Secure the switch with its fixing screws ensuring that it is level

Connecting the supply cable at the ceiling rose

Cables fed through and ceiling rose being fixed

36. Feed the other end of the switch cable, which you ran to the primary switch earlier, through the ceiling at the light point. Also feed through the end of a new length of suitable cable which will connect to the lighting circuit. Label these as 'Switch' and 'Supply' and ease them through the backplate of the new ceiling rose. Screw the backplate of the rose to the ceiling joist or noggin.

Supply cable stripped and prepared

37. Strip and prepare the conductors of the supply cable.

Connecting the supply Live to the ceiling rose

38. Connect the brown (old cable colour = red) one to the terminal block marked ‘LOOP’.

Connecting the supply Neutral to the ceiling rose

39. Connect the blue (old cable colour = black) to the terminal block marked ‘N’.

Connecting the supply Earth to the ceiling rose

40. Connect the green and yellow sleeved conductor to the terminal marked with the earth symbol but only secure loosely for the moment as another earth will also need to be connected here.

Connecting the switch cable at the ceiling rose

Strip and prepare the switch cable

41. Strip and prepare the switch cable.

Connecting the switch cable Live going to the switch

42. Connect the brown (old cable colour = red) to the terminal block marked ‘LOOP’.

Tagging the Live coming back from the switch

43. Tag the blue with a piece of brown sleeving (old cable colour = black; old tag colour = red) indicating that it is actually the live coming back from the switch and connect it to the live terminal at the end next to the live flex connection terminal .

Connecting the Earth

44. Connect the green and yellow sleeved conductor to the earth terminal. Ensure that both earth conductors are now firmly secured.

Lampholder connection

Lampholder preparation

45. Prepare and connect a lampholder to a suitable length of flex. For more information on this, see our Lampholder Fitting and Connecting article.

Feeding pendant flex through ceiling rose cover

46. Feed the other end of the flex through the ceiling rose cover and connect to the flex terminals.

Connecting the flex Live to the ceiling rose

47. Connect the brown (L) to the outer terminal next to the switch return conductor.

Connecting the flex Neutral to the ceiling rose

48. Connecting the blue (N) to the other outer terminal next to the supply cable neutral.

49. If your light fitting is metal the flex should also contain a Green / yellow (earth). This should be connected alongside the other earth conductors at the ceiling rose.

Flex conductors secured in retaining lugs

50. Ensure that the flex conductors are securly held in the retaining lugs provided.

Refitting the ceiling rose cover

51. Double check all your connections are correct, secure and have no exposed conductor showing. Fit the ceiling rose cover.

Connecting to the lighting circuit supply

52. The other end of the supply cable can now be connected to the lighting circuit.

53. You will need to decide the best method of providing the supply for this new light. The easiest way is by inserting a new junction box in the supply cable of the lighting circuit.

54. Unless the area where the junction box is going will be accessible, you will need to use a maintenance free type. In this example we are using a Wagobox maintenance free junction box.

Cutting in to the lighting circuit

55. Cut the cable of the lighting circuit next to where the junction box is to be fitted.

Strip and prepare the lighting circuit cable ends

56. Strip and prepare the new ends remembering to sleeve the bare earth conductors in the usual way.

Strip and prepare the supply cable

57. Strip and prepare the ends of the new supply cable as well.

Connecting the Live conductors

58. Connect the brown Live (old cable colour = red) conductors together in a suitable terminal connector.

Connecting the Neutral conductors

59. Connect the blue Neutral (old cable colour = black) conductors together in a suitable terminal connector.

Connecting the Earth conductors

60. Connect the green and yellow sleeved conductors together in a suitable terminal connector. In this example a cage clamp type terminal connector is being used. A push type connector would be equally suitable.

Securing the connectors inside the junction box

61. Secure the terminal connectors in the maintenance free junction box following the manufacturer’s instructions.

Securing the sheathed cable in the junction box

62. Secure the sheathed section of the cables in the cable clamps provided.

Mounting the junction box

63. Fix the lid of the junction box and mount the box on a suitable timber using the bracket provided.

64. Double check all your wiring and connections.

65. Once you are sure that all work has been completed correctly, switch the power back on at the consumer unit. In the case of removable fuses, replace the fuse for the circuit, and switch the power back on.

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