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Adding a new light and switch

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Caution

Electricity is dangerous and can be hazardous. In doubt? Call a qualified electrician.

Adding a new light and switch

Decide on the location of the new light and drill a hole through the ceiling at the position where you want the light. Next, above the ceiling, locate the hole, which can be made easier by poking something through from below, and determine its location to the nearest joist. If it is close then the ceiling rose can be fixed to that otherwise a piece of wood should be nailed between joists to provide a secure fixing point.

Decide on the location of the switch and mark out the mounting box - see Installing a electrical mounting box. Cut out a channel in the wall from the location of the new switch to the ceiling. Run a length of 2 core + earth 1mm2 cable from the ceiling rose location to the switch. The cable that in the channel should run through a length of conduit. The cable channel from the ceiling to the switch can now be plastered over and made good.

Switch

At the switch prepare the cable for connection see Preparing cable for connection. Connect the red conductor to the top screw terminal on the switch, and connect the black conductor to the bottom screw terminal. Place a length of green/yellow sleeving over the bare earth conductor and connect to the mounting box. The switch can now be screwed in place to the mounting box.

Ceiling rose

Attache the rose to the ceiling leaving a hole for the cable above to pass through. Pass the cable from the switch down to the ceiling rose nad prepare its end see Preparing cable for connection.

The terminal block on the ceiling rose is usually made up of one 2 terminal block, and two 3 terminal blocks. The black conductor from the switch cable should be connected into the two terminal block, the red conductor from the switch cable should be connected to the centre 3 terminal block. Fit the earth conductor with a length of green/yellow sleeving over the bare wire and connect to the big earth terminal on the ceiling rose.

Connecting to the existing lighting circuits

There are three ways to connect a new light and switch to the existing lighting circuits. Connecting to a loop-in rose of an existing light, from an existing junction box or from a new junction box which is probably the easiest way. Connecting to a loop-in rose means the cable supplying the new light is supplied from a ceiling rose of a light in a different room. Connecting to an existing junction box requires locating an existing junction box in the existing lighting circuit and running the supply cable from that.

Probably the easiest way to wire up a new circuit is to break into the existing circuit and fit a new junction box. The supply cable can then be run from there.Deciding on which method to use depends on your existing lighting circuits. Once decided, lay out and prepare all of the new parts of the circuit before switching off the mains supply and breaking into the existing circuit.

Run a length of 1mm2 cable from the ceiling rose to the position where it will connect to the existing lighting circuit. Prepare both ends of the new length of cable (see Preparing cable for connection) and at the ceiling rose connect the red conductor in the same terminal block as the one from the switch. Connect the black conductor to the other 3 terminal block. Finally connect the earth conductor to the earth terminal with the other earth conductor from the switch.

The remaining connection to be made at the ceiling rose is the connection to the bulbholder. See Connecting a flex to a bulbholder for details on how to do this. Connect the brown conductor from the bulbholder flex to the 2 terminal block with the black conductor from the switch. Connect the blue conductor to the 3 terminal connection block with the black conductors from the other cables. Finally connect the earth (green/yellow) conductor to the earth terminal with the other earth conductors. On the ceiling rose there are two lugs, one on either side, hook the brown and blue conductors around the lugs to prevent strain on the terminals. The case from the ceiling rose can now be screwed in place.

SWITCH OFF ELECTRICITY AT THE MAINS

The mains electricity should now be switched off and the fuse for the circuit you are working on should be removed. Now connect the new circuit to the existing lighting circuit. As mentioned previously there are three ways of doing this, you should already have decided which method you are using.

Connecting to an existing loop in rose Ensure the mains supply is still switched off. Unscrew the ceiling rose of the light to be connected revealing the terminals. Pass new cable through to the terminals from above. The red conductor should be connected to the central three terminal block with the other red (live) conductors. The black conductor should be attached to the three terminal block with the other black conductors and the blue conductor going to the light flex. Finally connect the earth conductor with the other earth conductors into the large screw terminal. The cover to the ceiling rose can now be replaced.

Connecting to an existing junction box

Ensure the mains supply is still switched off. Remove the cover of the junction box. Connect the red conductor of the new cable to the screw terminal with the three or more red conductors. Connect the black conductor with all the other black conductors and connect the earth conductor covered in a green/yellow sheath with other earth conductors to the earth terminal. Replace the cover of the junction box.

Connecting to a new junction box

Ensure the mains supply is still switched off. Break into the existing lighting circuit cable at the point you have run the new cable to. Strip the outer sheath and remove the sheath over the conductors trying to avoid cutting through them if possible. Secure the new junction box to a joist, and remove the three terminal screws of the junction box and place in the lighting cable you have just prepared. Lay the prepared cable into the screw terminals ensuring the earth wire is in the middle terminal. Screw the screws back in the terminals but not too tight. Connect the new cable to the appropriate terminal red to red, black to black and earth to earth, and tighten the terminals. The cover to the junction box can now be replaced.

The electricity can now be switched on and the new circuit tested.

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