Installing an electrical socket costs between €15 and €50 in materials. Calling in an electrician will cost €80 to €200 (including materials and labour). Many DIYers wonder whether they are allowed to install an extra socket themselves. The answer is nuanced: replacing an existing socket is permitted for everyone; adding a new socket to an existing circuit is also technically permitted but must comply with current wiring regulations. In this article you’ll find the rules, safety considerations and the step-by-step guide.
Are You Allowed to Fit Your Own Electrical Socket?
In the UK, electrical work in dwellings is governed by Part P of the Building Regulations. Like-for-like replacement of a socket in the same position is generally considered minor work and can be done by a competent DIYer. Adding a new socket to an existing circuit is also possible for a DIYer but must comply with BS 7671 (the IET Wiring Regulations). If you are in any doubt about the circuit capacity, have the installation checked by a registered electrician.
When to always use a qualified electrician:
- Installing a new circuit from the consumer unit
- Fitting an RCD (residual current device)
- Routing cables through structural walls
- Outdoor sockets (IP44 rating and RCD protection mandatory)
DIY vs. Electrician
| DIY | Electrician | |
|---|---|---|
| **Replacing an existing socket** | €15 – €30 (materials) | €80 – €150 |
| **Extra socket (on existing cable)** | €20 – €50 | €100 – €200 |
| **New socket with new cable** | Strongly not recommended | €150 – €350 |
Materials Required (replacing or adding a socket)
| Material | Price |
|---|---|
| Socket (earthed) | €5 – €20 |
| Surface-mounted or flush back box | €3 – €8 |
| Cable connector or junction | €2 – €5 |
| Faceplate | €3 – €8 |
| **Total** | **€13 – €41** |
Tools
- Voltage tester (essential!)
- Screwdrivers (flat and cross-head)
- Wire strippers
- Cordless drill (for flush back box)
Step-by-Step Guide: Replacing a Socket
Step 1: Switch the circuit OFF
Open the consumer unit and switch off the circuit breaker supplying the socket. Verify with a voltage tester that there is no live voltage at the socket. Always do this — even if you are certain which breaker controls it.
Lock out the breaker with a piece of tape or attach a notice: “Do not switch on — work in progress”. This prevents anyone else from switching the circuit back on while you are working.
Step 2: Remove the old socket
Remove the faceplate (usually 1–4 screws or a clip-on fitting). Gently pull the socket out of the back box — the wiring is connected, so do not pull too hard.
Make a note (or take a photograph) of which wires connect where:
- Brown or red = live (L)
- Blue or black = neutral (N)
- Green/yellow = earth (E)
Unscrew the wires from the terminals.
Step 3: Connect the new socket
Connect the wires to the new socket in the same order:
- Brown/red → L (live terminal)
- Blue/black → N (neutral terminal)
- Green/yellow → E (earth terminal)
Use an earthed socket — this is required for all modern installations.
Wires too short? Use connector blocks (Wago connectors) to extend them. Wires too long? Coil them gently in the back box — do not crush or cut them.
Step 4: Refit the socket
Push the socket back into the back box. Ensure the wires are not pinched. Screw the socket in place (not too tight — porcelain and plastic break if overtightened). Fit the faceplate.
Step 5: Test
Switch the circuit breaker back on. Test the socket with a socket tester or plug in a lamp and check it lights. Use the voltage tester to verify the earth connection is correct.
Adding an Extra Socket (Spur)
If you want to add a new socket alongside an existing one (a spur), follow the same process with one additional step:
- Open the existing socket (circuit off!)
- Check whether there are spare terminals available, or use a junction box
- Run a new cable from the existing socket to the new position
- Use the same colour coding
- Connect the new socket
Important: check that the circuit has adequate capacity. A standard 32 A ring main circuit is suitable for the loads typically found in a room. Add up all the appliances connected to that circuit.
Surface-Mounted vs. Flush Socket
Flush socket — recessed into the wall. Neater and safer. Requires a flush back box in the wall (drilling required for solid concrete or blockwork).
Surface-mounted socket — mounted on the wall surface. Easier to install (no back box required). Less attractive but perfectly suitable for garages, cellars and outbuildings.
Safety Rules
- Never work live. Always switch off the circuit and check with a voltage tester.
- Use earthed sockets. Non-earthed (two-pin) sockets are obsolete and unsafe for appliances with metal casings.
- Use the correct cable cross-section. Standard domestic cable: 2.5 mm² for wall sockets, 1.5 mm² for lighting. Never use undersized cable.
- Always use IP44 or higher outdoors. Indoor sockets are not water-resistant.
- Have work checked if in doubt. A registered electrician can test the installation and issue an electrical safety certificate.
Frequently Asked Questions
Am I allowed to fit a socket myself?
Like-for-like socket replacement is generally permissible for a competent DIYer under Part P of the Building Regulations (UK). For new circuits, solar panels or EV chargers, a registered electrician is required.
How do I find out which circuit a socket is on?
Switch the socket on (e.g. by plugging in a lamp). Then switch circuit breakers off one at a time in the consumer unit until the lamp goes out. Record this for future reference.
What does a flashing light on my voltage tester mean?
Your voltage tester is detecting live voltage. Switch off the correct circuit breaker and check again. If it still indicates voltage, you have switched off the wrong breaker.
How many sockets can be on one circuit?
There is no fixed legal maximum for the number of sockets on a circuit, but the total load must not exceed the circuit breaker rating. As a rule of thumb: no more than 6–8 sockets on a 16–20 A circuit for general domestic use.
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