Converting a single socket outlet to a double socket

• Switch off the power at the consumer unit and turn off the MCB or remove the fuse that protects the circuit that supplies the socket you will be working on. Plug in and turn on a lamp to make sure that the circuit is dead.
• Unscrew the faceplate from the existing socket mounting box and unscrew the cores from the terminals.
• Position the pattress level over the existing mounting box. After checking the pattress is horizontal with a spirit level, use a bradawl to mark the position of the fixing holes on the wall.
• Take the pattress away from the wall to drill the holes and insert wall plugs.
• Having fed the cable through the back of the pattress, screw it to the wall.
• Straighten the tips of the cable cores using a pair of pliers. If the earth cores are bare, cover them with green-and-yellow sleeving, leaving about 15mm of core exposed to connect to the terminal.
• Connect the cores to the appropriate terminals on the back of the face-plate of the pattress. Blue/Neutral to the terminal marked N, Brown/Live to the terminal marked L and Green-and-yellow/Earth to the terminal marked E
• Additionally, if the mounting box is metal, a flying-earth needs to be connected from the earth terminal on the back of the faceplate to an earth terminal in the mounting box. This comprises of a small off-cut of core covered with green-and yellow sleeving, which ensures the mounting box is properly earthed.
• Carefully screw the face-plate of the pattress to the mounting box ensuring the screws don't pinch any of the cores.
• Switch the MCB back on or replace the fuse at the consumer unit and restore the mains power.

If you are converting a surface-mounted single socket to a surface mounted double socket, the method is the same except you remove the existing mounting box and replace it with a double or triple socket surface-mounted box.

This involves making the recess in the wall larger to accommodate the bigger mounting box.

• Switch off the power at the consumer unit and turn off the MCB or remove the fuse that protects the circuit that supplies the socket you will be working on. Plug in and turn on a lamp to make sure that the circuit is dead.
• Unscrew the faceplate from the existing socket mounting box and unscrew the cores from the terminals.
• If the existing mounting box is located on a plasterboard wall, unscrew the fixings and remove it. Then enlarge the hole using a padsaw taking care not to damage the cable.
• If the existing mounting box is fitted to a masonry wall it is recommended you enlarge the recess by half the required distance either side of the mounting box. Using a power drill to mark the outline of the new recess by drilling a series of holes around its perimeter. With the outline marked, chop out the new recess to the correct depth with a bolster and a lump hammer taking care not to damage the cable.
• Remove the old mounting box.
• Press out the plastic tab in the back of the new mounting box to make a hole for the cable and insert a grommet into the hole to prevent damage to the cable.
• Feed the cable though the hole in the back of the mounting box and fit the box in the hole.
• If you are fitting a Clip-in dry-lining mounting box, the box should clip in to place as you slide it into the hole. If this does not happen, push the lugs inside the box outwards.
• If you are fitting a mounting box to a masonry wall, mark the screw holes, then drill and plug the holes to screw the mounting box to the wall.
• Straighten the tips of the cable cores using a pair of pliers. If the earth cores are bare, cover them with green-and-yellow sleeving, leaving about 15mm of core exposed to connect to the terminal.
• Connect the cores to the appropriate terminals on the back of the new face-plate. Blue/Neutral to the terminal marked N, Brown/Live to the terminal marked L and Green-and-yellow/Earth to the terminal marked E
• Additionally, if the mounting box is metal, a flying-earth needs to be connected from the earth terminal on the back of the faceplate to an earth terminal in the mounting box. This comprises of a small off-cut of core covered with green-and yellow sleeving, which ensures the mounting box is properly earthed.
• Screw the new face-plate to the mounting box.
• Switch the MCB back on or replace the fuse at the consumer unit and restore the mains power.