One way lighting (page 1)

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Loop or junction box light circuit

Switch off the power supply at the consumer unit, and remove the fuse for the circuit from which you are going to take the supply for the new light.

Examine the cabling and identify the system which has been used. This may be the junction box type or loop type or a combination of the two.

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

Locating the light and switch

Having decided upon the location of the new light, 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. Otherwise, mount a wooden batten between the two nearest joists to provide the fixing.

Decide where you want the switch for this light.

Check that there are no cables, pipes etc buried below the surface. Cut out the wall to mount the switch box in the same way as for socket boxes. Mark a vertical line up to the ceiling above, and chase out the plaster to provide for the switch cable. Remember to wear safety goggles when cutting out. Above this chase, make a hole through the ceiling.

Installing the lighting switch cable

Feed a suitable cable ( see lighting circuits for details) through the hole in the ceiling from above down to the switch. Remember to allow sufficient cable for making the connections at both ends.

Remove a blanking piece from one of the switch box sides and fit a protective grommet. Feed the cable through, then strip and prepare the conductors. Fasten the mounting box in the recess

Tag the black conductor with a piece of red insulation tape. Connect this to the bottom terminal on the switch, (most one way single gang switches have the top labelled).

Connect the red conductor to the top terminal.

Connect the earth, suitably sleeved, to the earth terminal on the metal box.

Double check your connections and ease the switch back to the wall folding the cable carefully into the box. Secure the switch with its retaining screws tightening them alternately to draw it back evenly.

Secure the cable in the chase in the wall using cable clips. Now take the other end of this cable and feed it through the hole made in the ceiling earlier to the light fitting. Label it 'switch'.

Lighting circuit supply

You will now need to decide the best method of providing the supply for this new light. This may be done most easily by inserting a new junction box in the supply cable of the lighting circuit, in which case the cable will need to be cut and the junction box securely mounted on a joist. Double check that the power is off before cutting a cable.

Allocate one terminal for live, one for neutral and one for earth.

Cut the cable, strip and prepare the conductors. Sleeve the earth conductors with green and yellow sleeving. Connect the conductors to the terminals. The two reds to one of the outer terminals, the two blacks to the other outer terminal and the two sleeved green and yellow to the middle terminal.

Continued...

• Two way lighting
• Lighting circuits