Socket outlet back boxes for mounting power points in plasterboard walls are made of plastic and have special mounting lugs to hold them in position.
1. Hold the box in the desired position against the wall making sure it is level by laying a small spirit level along the top of it.
2. Mark around the perimeter with a pencil and check that there are no cables or pipes below the surface in this area.
3. The point on a padsaw allows it to pierce the plasterboard. But, you may find it easier to use a cordless drill with a masonry drill bit to make a hole in each of the four corners of sufficient diameter to allow you to insert a padsaw.
4. Insert the padsaw into one of the corners and cut carefully though the plasterboard along the pencil line towards the next hole. Keep the pad saw straight and square as you cut.
5. Once you have connected all the corners with the cut line, remove the waste.
6. Remove the blanking piece from the corresponding cable entry point on the plastic box. These are held in place with small lugs and are easily pushed out.
7. Feed the cable carefully through the most suitable access point of the box, making sure you pull through enough cable to easily allow for trimming and connecting the socket outlet.
8. Push the plastic fixing lugs on each side of the box backwards so that they are farthest away from the face. Make sure that they are also fully retracted.
9. Place the box in the hole and adjust the plastic lugs at each side by pushing them outwards then towards the front so that they are gripping against the back of the plasterboard.
10. The lugs will hold the box lightly in place for the moment.
11. These boxes are held securely in place when the face plate retaining screws are tightened. This is done after the socket has been connected up. The action of tightening sandwiches the plasterboard between the lugs and the rim of the box.