Telephone Extensions


If you already have a telephone line you can install extensions, provided your line is connected to a master socket - a square white box with a shuttered socket aperture. A master socket can only be fitted by an authorized engineer from your telephone company. There must no more than 50m (54yd) of cable between the master socket and the furthest telephone extension. Make sure you have a socket converter: this plugs into the master socket and has a length of cable attached and as many extension sockets as you need plus enough cable cleats to fix the cable at 300mm (12in) intervals. You will also need an insertion tool. If you buy an approved telephone extension 'kit', this will normally be included.


Push the green wire with white rings into the connection marked '1'; the blue wire with white rings into '2'; the orange wire with white rings into '3'. On the other side of the socket fit the white wire with orange rings into connection '4'; the white with blue rings into '5', and the white with green rings into '6'.

To add more telephone extensions - the maximum number of extension sockets is normally five - wire them from the first extension, connecting the wires in the order stated above and push them into the connection on top of the existing wires.

Step by Step Instructions

1 Start at the master socket

Decide where you want to fit the extension and plan the shortest possible route for the cable. This can be fitted along walls or skirting boards, above ceilings and below floors, but must be kept at least 50mm (tin) away from mains electric cabling.

2 Fix the cable

Working from the master socket, fit the cable in place with cleats. The socket converter should reach the socket easily, but don't plug it in until the extensions have been fitted and connected. When the cable reaches the extension, cut the cable leaving about 75mm (3in) spare.

3 Wire the extension

Use a sharp knife to cut away the cable entrance hole at the bottom of the plate. Strip off about 32mm (1%in) of the outer sheath of the cable with a trimming knife. Use the insertion tool to connect the six wires as explained in the box (left).

4 Fix extension socket to wall

At the position marked for the extension, drill and plug a hole in the wall.

Unscrew the front plate of the extension socket. Screw the socket into the drilled and plugged hole in the wall or screw it to the skirting board. Fit the front plate using the two screws provided.

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