DIY GUIDE · ELECTRICAL · CHECKED OCTOBER 2026
How to replace a socket or light switch yourself
Half an hour per accessory. €14–€41 for a voltage tester and a new socket or switch.
Switch off, prove dead, photograph, swap like for like, test. Same accessory, same wires, same box — and never in a bathroom.
- Every step, start to finish
- Checked October 2026 — sources at the end
- Honest about when to call a pro
FIRST, THE HONEST ANSWER
Do it yourself, or get a fitter?
Do it yourself if…
- You are replacing a socket or switch with the same type, on the same wires, in the same box
- You can find and switch off the circuit at the board, and you own or will buy a voltage tester
- The wiring behind the faceplate is in good condition, with no scorching, brittle insulation or loose cores
- The accessory is not in a bathroom or shower room
Get a pro if…
- You want a socket or switch moved, added, or turned into a different type, such as a dimmer on a circuit not suited to one
- The old accessory shows scorch marks, melted plastic or a burning smell
- The wiring has old rubber insulation, no earth, or does not match the colours and layout in this guide
- The accessory is in a bathroom, shower room or outside
Safety first
- Isolate the circuit and prove it dead at the point of work before you touch anything. The HSA's electricity guidance says the tester should itself be proved, preferably just before and just after the test.
- Lock off the breaker with tape and a note so nobody switches it back on while you work.
- Safe Electric recommends testing your RCDs by pressing their test button about every three months, and having a Registered Electrical Contractor check one that trips for no clear reason.
- Stop if you find scorching, melted plastic, brittle insulation or no earth. Those are signs of a fault, not a like-for-like job.
- Never work on electrics in a bathroom or shower room yourself; even a like-for-like swap there is restricted work in Irish law.
Stop here: Stop here: anything new, anything at the board, and bathrooms
Under Irish law, the 2013 Restricted Electrical Works Regulations, S.I. No. 264 of 2013, made under the Electricity Regulation Act, restrict new circuits, any change at the distribution board and any modification, installation or replacement of an electrical installation in a special location such as a bathroom to a Registered Electrical Contractor, who must test and certify the work. Minor works such as replacing a light switch or socket front like for like are outside that restriction. The CRU prosecutes unregistered restricted work, and the contractor's Completion Certificate is asked for on sale, remortgage and insurance. How to hire a socket and switch fitter →
| MATERIAL | COVERAGE | FOR THIS JOB |
|---|---|---|
| Replacement socket or switch | Same type and gang count, to suit the box depth | One |
| Green-and-yellow sleeving | Any bare earth core must be sleeved | A short length, if missing |
| Insulating tape and a pen | To label the cores of a switch or a socket with several cables | One roll |
Will the new plate fit the box
Fit check: box depth available − accessory depth needed ≥ room for cables. If the box is 35 mm deep and the new USB socket needs 35 mm, there is no room left for the cables; a 47 mm box or a slimmer accessory is needed.
Measure from the wall surface to the back of the box with a ruler, avoiding the cables. The accessory's depth is on its pack or its sheet.
A single switched socket for a single switched socket; a one-way switch for a one-way; a two-way for a two-way. Count the gangs and look at the back of the old one before you buy. Swapping a plain switch for a dimmer, or a socket for one with USB ports, is still like for like only if it fits the same box and the same wires and suits the circuit.
Every accessory needs a minimum box depth behind it. Decorative flat plates and USB sockets often need more depth than the old plastic one. Measure the depth of the existing box before you buy, or the new plate will not sit flat and its terminals will strain the cables.
A metal faceplate must be earthed. The socket maker we read says an earth connection should always be made between the mounting box's earth terminal and the socket's earth terminal. If the old accessory had a flying earth lead from the box, the new one must have it too.
Modern Irish wiring uses brown for live, blue for neutral and green-and-yellow for earth. Older installations use red for live and black for neutral. Light switch cables can use a brown or a black core as a switched live, often with brown sleeving. If what you see does not follow these patterns, stop.
You need a two-pole voltage tester or a proper voltage indicator, not just a neon screwdriver. The HSA's electricity guidance says the tester should itself be proved, preferably just before and just after you test the circuit. A plug-in socket tester is a useful extra check afterwards.
THE PART THAT DECIDES THE FINISH
Before you start — what you find behind the faceplate
With the circuit off and proved dead, unscrew the old faceplate and ease it out. Match what you see to one of these before you undo a single wire.
One cable into a socket
A single brown, blue and earth core, each in its own terminal.
- Photograph the back of the old socket from straight on
- Check each core for cracks in the insulation and scorching
- Check the earth core is sleeved
- Note whether a separate earth lead runs from the back box to the socket
Two or three cables into a socket
Two or three cores in each terminal, from a ring or a radial circuit.
- Photograph it clearly so you can see which cores share which terminal
- Keep each group together with a twist of tape before you release them
- Do not separate cores that were together in one terminal
- If one core is loose or blackened, stop and call a Registered Electrical Contractor
A one-way light switch
Two cores at the switch, sometimes brown and a sleeved black or blue.
- Photograph which terminals are used, often marked COM and L1
- Check whether the earth is connected to the back box
- Remember one core is a switched live, even if its colour suggests otherwise
- If you see more than two cores plus earth, you have a two-way or a feed through; label each
A two-way or multi-gang switch
Three cores per gang, or several gangs on one plate.
- Label every core with tape and a number before you undo it
- Photograph each gang separately
- Switch off any second circuit; a two-way switch can be fed from elsewhere
- If the layout is unclear, stop and get a Registered Electrical Contractor
THE JOB
How to replace it
Switch off and lock off
10 minGo to the board and switch off the circuit that feeds the accessory. For a light switch, that is the lighting circuit; for a socket, the socket circuit. If you are not sure which, switch off the main switch. Put tape over the switched-off breaker and a note on the board so nobody turns it back on.
- Check the circuit chart on the board, but never trust it alone
- Turn on a lamp in the socket first so you can see it go off
- Keep a head torch on you once the lights are off
Mistake to avoid: Trusting the label on the board. Circuits are often mislabelled, and the only proof is the tester.
Prove it dead
10 minProve your tester works on a socket you know is live, then test the accessory you are about to replace: between live and neutral, live and earth, and neutral and earth. Then prove the tester again on the known live socket. Only when every test shows dead do you open the faceplate. The HSA's electricity guidance sets out exactly this check before and after.
- Test with the tester's probes on the terminals once the plate is eased forward
- Test every core in a box with several cables
- If anything shows live, stop and find the right circuit
Mistake to avoid: Testing only once and assuming the tester works. A flat battery in a tester reads dead on a live terminal.
Do the prep from the cards above
10 minEase the faceplate forward and look. Match it to a card above, photograph it, check the cores and sleeving, and label groups of cores with tape. If anything is scorched, brittle, loose, unsleeved and bare, or does not match, stop here.
- Hold the plate by its edges, not by the terminals
- Look for a separate earth link to the box
- Keep the old screws if the new ones are too short
Mistake to avoid: Pulling the old accessory out hard. The cores pull out of their terminals and you lose which went where.
Release the old accessory
5 minLoosen each terminal screw and draw the cores out, one terminal at a time, keeping each group together as it was. Set the old accessory aside with its screws.
- Loosen, do not remove, terminal screws
- Keep cores pointing out of the box so they do not tangle
- Wipe dust out of the box with a dry brush
Mistake to avoid: Undoing every terminal at once. A group of cores comes apart, and on a socket with three cables you can no longer tell the ring from the spur.
Prepare the cores
10 minLook at each core end. It should be clean copper, straight, with the insulation up to the terminal and no bare wire showing outside it. If an end is nicked or blackened, cut it back and strip a fresh end of the right length, only if there is enough slack. Sleeve any bare earth.
- Strip only as much as the terminal takes
- Twist multiple cores lightly together before they go into one terminal
- Do not shorten cables that are already tight in the box
Mistake to avoid: Leaving bare copper showing outside the terminal. It can touch the box or another core when the plate is pushed back.
Connect the new accessory
10 minConnect each core or group to the same terminal on the new accessory as on the old one: live to L, neutral to N, earth to the earth terminal, and the earth link to the box if there is one. On a switch, match COM and L1 or L2 exactly. Tighten each screw securely; the socket maker we read says firmly but not overtightened.
- Tug each core gently to make sure it is held
- Check no strand of copper has escaped the terminal
- Follow your photograph for every connection
Mistake to avoid: Putting live and neutral into each other's terminals. The socket works, but the switch then breaks the neutral and leaves the appliance live.
Fit the faceplate
5 minFold the cables neatly back into the box, without crushing or trapping them, and push the accessory into place. Fit the screws and tighten them evenly until the plate sits flat. Do not overtighten; plastic plates crack.
- Fold cables in a loose S rather than pushing them in
- Check no core is trapped between the plate and the box lug
- Level the plate by eye before final tightening
Mistake to avoid: Forcing the plate flat over a bundle of cables. A core gets pinched against the box edge and its insulation is cut.
Switch on and test
10 minRemove your tape from the breaker and switch it on. For a socket, plug in a socket tester and read its lights, then a lamp to check it works. For a switch, check the light goes on and off from every switch that controls it.
- Check the RCD has not tripped; if it has, switch off and recheck
- Feel the faceplate after an hour of use; it should stay cool
- Test two-way switches from both ends
Mistake to avoid: Assuming it is right because the light works. A socket can supply power and still be wired wrongly; the tester shows it.
Check and tidy
10 minLook again at the plate, test the RCD with its test button as Safe Electric recommends every few months, and put a date on the board label if you updated it. Bag the old accessory for recycling.
- Update the circuit chart if you found it wrong
- Keep the new accessory's leaflet with your house papers
- Show the household where the board is and what you labelled
Mistake to avoid: Leaving the circuit chart wrong. The next person, perhaps an electrician, trusts it and switches off the wrong circuit.
The mistakes that show
- Trusting the board label instead of proving the circuit dead
- Using a tester that was not proved before and after
- Undoing every core at once and losing the grouping
- Leaving bare copper outside a terminal
- Skipping the earth link to a metal box
- Treating a bathroom switch or socket as like for like
Stop here and get a Registered Electrical Contractor
- You want a new socket, a moved switch or anything on a new circuit
- The work is in a bathroom, shower room or outside
- You find scorching, damaged insulation, no earth or wiring you cannot match
- Anything at the board needs changing, including fitting a new breaker
| WHAT YOU SEE | WHY, AND THE FIX |
|---|---|
| The breaker or RCD trips when switched on | A core is touching the box or another core, or connections are swapped. Switch off, prove dead, and recheck every connection against your photo. |
| Socket tester shows a fault | Live and neutral swapped, or earth not connected. Switch off, prove dead, correct the connection and test again. |
| Light does not come on | A switch core is in the wrong terminal or not tight. Check COM and L1 against your photograph. |
| Two-way switching no longer works | The cores on one switch have been moved between terminals. Match each labelled core to its original terminal. |
| Faceplate will not sit flat | The box is too shallow or the cables are bunched. Rearrange the cables or fit a slimmer accessory; a deeper box is an electrician's job. |
| The new faceplate gets warm | A loose terminal. Switch off, prove dead and tighten every terminal; if it continues, call a Registered Electrical Contractor. |
| You found scorching inside the box | A connection has overheated before. Stop and have the circuit checked by a Registered Electrical Contractor. |
| Old red and black wiring with no earth | Old wiring may not be safe to reuse. Leave it and get a Registered Electrical Contractor to inspect it. |
WHAT YOU SAVE
What it costs to do it yourself
| Voltage tester | €11.95–€13 |
|---|---|
| Plain double switched socket or switch | €1.95–€3.95 |
| Plug-in socket tester | €13 |
| Decorative double socket | €14.99 |
| Total | €14–€41 |
| DIY total | €14–€41 |
Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.
The accessory is usually the cheapest part; the tester is the investment, and it is the one tool you must not skip.
RATHER NOT?
Socket and switch fitters near you, with prices shown
The ones who cover your area, nearest first, with one score from every review. No account needed to look.
Or post the job free and let them come to you.
Over the next few days, feel the faceplate after heavy use, such as a heater or kettle. It should stay cool. Warmth means a loose connection; switch off and check.
Press the RCD's test button every few months, as Safe Electric recommends. It should trip at once; reset it after.
An old socket or switch is small electrical waste. Mywaste.ie says items like this go to a WEEE drop-off point or a civic amenity site, free of charge; never in the household bin.
Safe Electric suggests a home installation is inspected and tested about every five years by a Registered Electrical Contractor, and sooner if fuses blow repeatedly or lights flicker.
Replacing a socket or light switch like for like: questions people ask
Yes, if it is a like-for-like replacement on the same wires in the same box, outside a bathroom. The Restricted Electrical Works Regulations treat that as minor work. New sockets, new circuits and bathroom work are for a Registered Electrical Contractor.
Yes, like for like, after switching off the lighting circuit and proving it dead with a tested tester. Changing a switch in a bathroom is restricted work.
Not for a like-for-like replacement. Restricted work by a Registered Electrical Contractor comes with a Completion Certificate.
Brown for live, blue for neutral and green-and-yellow for earth in modern wiring. Older wiring uses red for live and black for neutral.
If it replaces an existing socket in the same box, on the same wires, and the box is deep enough, it is like for like. Adding a new socket is a job for a Registered Electrical Contractor.
Locufy's Irish price guide puts socket and switch installation at €80–€200 per point, typically €120. New points and circuits cost more.
MORE GUIDES
More DIY guides
Sources — checked October 2026
- BG Electrical — socket setup and wiring instructions: replacing an existing socket, earth link to the box, terminal screws
- HSA — guide to Part 3 of the General Application Regulations 2007: electricity
- S.I. No. 264 of 2013 — Electricity Regulation Act 1999 (Restricted Electrical Works) Regulations
- Safe Electric — restricted and controlled electrical works
- Safe Electric — home safety: RCDs, periodic inspection, householder checks
- CRU — RGI and Safe Electric schemes
- MyWaste.ie — electrical items
- Ganly's — electrical accessories: sockets, switches, voltage detector (price check)
- DIY.ie — electrical testing: voltage and socket testers (price check)
- Woodie's — switches and sockets (price check)