Big deals

PLUS ALL OUR LATEST OFFERS Shop now

How to upgrade a socket

Difficulty rating: Medium

These tasks may be tricky so will suit you if you're experienced in DIY, or simply love a challenge.

Before you get started on any of our 'how to' guides, please take a moment to read through our DIY safety tips.

1. Do you need a multiple socket?

  • Are you running several units of low-wattage equipment - a hi-fi system, for example? Then it's better to plug the individual units into a four-point trailing socket or connect the flexes to a four-way multi-adaptor.
  • Plug your computer into a fused trailing socket with an anti-surge device.

 

Be aware...

If you're not qualified, any electrical work you do should be inspected, tested and certified by a qualified electrician. Building Regulations recommend that electrical items are fitted by a qualified electrician.

 

2. Switching off the power supply

  • Always switch off your power supply at the fuse box (consumer unit) before doing any electrical work.
  • You can do this two ways. First, you can switch off the miniature circuit breaker (MCB) for the circuit you'll be working on and put red insulating tape over the MCB so it's not switched on accidentally.
  • Or you can turn off the main switch, remove the circuit fuse, then turn on the main switch again to restore power to the rest of the house.
 

3. Making the right connections

  • At the back of a single or double socket, the terminals are marked L (Live), N (Neutral) and E (Earth).
  • Wiring colours in the UK were changed in April 2006. The table below shows the wiring colours for older installations (pre-April 2006) and all new wiring, and the correct terminals to connect each wire into:
 
Older wiringNew wiringConnects to
REDBROWNL or LIVE (fig. 2)
BLACKBLUEN or NEUTRAL (fig. 2)     
YELLOW/GREEN     YELLOW/GREEN     E or EARTH
 
  • The green/yellow earth wire connects both to E and to the terminal of the mounting box (fig. 3).
  • Tighten terminal screws securely and give wires a good tug to check they're firmly fastened.
 
A typical power ring circuit
Figure 1
Make the right connections – see Section 3 for the correct old and new wiring colours.
Figure 2
The bare earth wire connects to both E and the terminal of the mounting box.
Figure 3

4. Check the wiring to the wall socket

  • If the wiring is only or mainly two-wire cable, it's probably very old and should be replaced (fig. 4). Contact a qualified electrician.
  • Check that wiring regulations allow you to upgrade the wall socket (fig. 1).
  • Here's how to check whether you can safely convert a socket:
  • Plug a table lamp into the socket and switch it on. Isolate the power at the consumer unit. If the light goes out you have the correct circuit.
  • Remove the socket from its mounting box and count the cables:

 - If you see three cables, you can convert the socket.

 

- If you see two cables, both twin and earth, disconnect the red/brown and black/blue wires from the terminals and separate them. Unplug all appliances on that ring circuit. Take a continuity tester and, following the tester instructions, touch one probe on each of the red/brown wires. If the tester shows continuity, the plug socket is on the ring circuit and can be converted.

 

- If you see one cable, trace the cable to its source. If it joins a socket or junction box on the ring circuit, the wall socket is safe to convert.

 
If the wiring is only or mainly two-wire cable, it's probably very old and must be replaced.
Figure 4

5. Replacing a surface single with a surface double or triple

Disconnecting the old socket
  • Unscrew the old socket from its mounting box and disconnect all the wires from their terminals.
  • As the wires are disconnected, label each one clearly with the terminal it was connected to (fig. 5).


Removing the mounting box

Unscrew the surface box and pull it away from the cables. Take care not to let the cables fall down inside a hollow partition wall.


Fixing the new mounting box
  • Prepare the new surface box by removing the 'knockouts' on the back of it and smoothing away rough edges with a fine file. The cables then pass through the knockouts.
  • Check that the outer insulation is within the box. The box can then be screwed to the wall (fig. 6).


Earthing the new socket

Enclose the earth wire with a new 150mm length of yellow/green earth cable and connect to the earth terminal.


Connecting the new socket
  • Check that any bare earth wires are enclosed in green/yellow sleeving.
  • Connect the new socket to the wires. Do this by loosening the terminal screws on the brass fittings and connecting each wire to the terminal with the same marking as its label.
  • There may be more than one wire per terminal. Push the wire or wires into the terminal and tighten the screw. Make sure only the copper cores of the wires enter the terminals and that the insulation isn't trapped under the terminal screw.
  • Check that the wires are connected to the correct terminals - then you can remove the labels.


Securing the new socket

Screw the socket to the box, switch on the power supply and check that the new socket is working correctly.

 
Mark each wire with the terminal it was connected to - see Section 3 for the correct old and new wiring colours.
Figure 5
The cables pass through the knockouts in the box. The box is then screwed to the wall
Figure 6

6. Replacing a flush single with a flush double or triple

Disconnecting the old socket

Unscrew the old socket from its mounting box and disconnect all the wires from their terminals. Label each wire with the terminal it was connected to (fig. 5).


Removing the old mounting box
  • First, the recess needs enlarging. Mark the size of the double box on the wall over the single box.
  • If the wall is stud partition, cut a larger hole in the plasterboard with a pad saw or sharp handyman's knife.
  • If the wall is solid, use a masonry bit to drill holes 25mm deep on either side of the single box (fig. 7).
  • Then chop out the remaining masonry with a club hammer and bolster chisel.
  • Now unscrew the metal box and pull it away from the cables. Take care that the cables don't fall down inside a hollow partition wall.


Fixing the new mounting box
  • Prepare the new box by removing the knockouts and inserting a rubber grommet in each.
  • Pass the cables through the knockouts into the new box. Make sure the outer insulation is within the box.
  • Screw the box into the new enlarged recess, then coil the wires inside the box.
  • Fill any gaps between the box and the wall (fig. 8) and allow filler or plaster to dry thoroughly.


Earthing the new socket

Enclose the earth wire with a new 150mm length of yellow/green earth cable and connect to the earth terminal.


Connecting the new socket
  • Check that any bare earth wires are enclosed in green/yellow sleeving.
  • Connect the new socket to the wires. Do this by loosening the terminal screws on the brass fittings and connecting each wire to the terminal with the same marking as its label.
  • There may be more than one wire per terminal. Push the wire or wires into the terminal and tighten the screw. Make sure only the copper cores of the wires enter the terminals and that the insulation isn't trapped under the terminal screw.
  • Check that the wires are connected to the correct terminals - then you can remove the labels.


Securing the new socket
  • Screw the socket to the box, switch on the power supply and check that the new socket is working correctly.


Helpful hint...

Always switch off the power supply at your consumer unit (fuse box) before starting electrical work. If you're unsure call a qualified electrician.

 
If the wall is solid use a masonry bit to drill holes 25mm deep on either side of the single box
Figure 7
Fill any gaps between the box and the wall. See Section 3 for the correct old and new wiring colours.
Figure 8

Tools for the job


You may also be interested in...


Was this guide useful?