Homeowner guide
Changing light bulbs (lamps) safely
Changing a lamp is one of the few electrical jobs almost every householder does. This guide covers every lamp cap you are likely to meet in a UK home — BC, SBC, ES, SES, GU10, MR16, G9, G4, GX53 and fluorescent — how each one comes out, how to isolate safely first, the wattage and enclosure limits that matter, and the warning signs that mean the fitting itself needs an electrician rather than another bulb.
Isolate first — every time
A wall switch may only break the line conductor. In older or incorrectly wired installations a lampholder can still be live with the switch off. Turn the lighting circuit off at the consumer unit and lock or label it before reaching into any fitting. Electricians follow the full safe isolation procedure.
Step by step
The sequence below applies to any lamp in a domestic dwelling. Most bulb-change injuries in the UK are falls from unstable platforms and cuts from shattered glass — not shocks — so the ladder and the cool-down matter just as much as the isolation.
- 1
Switch off and isolate
Turn the light off at the wall switch. For any ceiling fitting, downlight, or anything you need to reach into, also switch off the lighting circuit breaker at the consumer unit. A wall switch may only break the line conductor, so a lampholder can still be live at the switched-off position in an older or wrongly wired installation.
- 2
Prove it is dead if you can
Homeowners should not be probing terminals. If a lamp has broken in the holder or you need to touch anything other than the lamp itself, that is electrician's work — see the safe isolation procedure used by professionals.
- 3
Let the old lamp cool
Halogen and older incandescent lamps reach several hundred degrees. Give them at least ten minutes and use a dry cloth or glove. A hot glass envelope can shatter when gripped.
- 4
Work from a stable platform
Use a proper step ladder on a level floor, not a chair, a bed or the arm of a sofa. Falls while changing bulbs cause far more domestic injuries than shocks do. Have someone foot the ladder where possible and keep both hands free.
- 5
Remove the old lamp correctly
Bayonet: push in gently and twist anticlockwise. Screw: turn anticlockwise. GU10: push up and twist anticlockwise a quarter turn — flush recessed GU10s often need a rubber suction (sucker) tool, lightly moistened and pressed against the cold lamp face, to get enough grip to turn it. MR16 / G9 / G4: pull straight out without twisting. If the lamp resists, stop — forcing it is how holders break and glass shatters.
- 6
Check the holder before fitting the new lamp
Look for browning, cracking, melted plastic, black soot marks or loose, sunken contacts. Any of these means the fitting is overheating or arcing and needs replacing by an electrician — do not simply fit a new lamp and carry on.
- 7
Fit the new lamp — matched type and rating
Match the cap, the voltage, the colour temperature and the maximum wattage marked on the fitting. Never exceed the maximum wattage on the luminaire label. Do not handle halogen capsules with bare fingers.
- 8
Restore power and check
Switch the circuit back on at the consumer unit, then the wall switch. If the new lamp flickers, buzzes, fails to strike or trips the breaker, switch it off again and stop — that is a fault, not a bad bulb.
Every lamp cap you'll find in a UK home
Take the old lamp to the shop, or photograph the cap and measure the metal base across its widest point. Cap codes describe the fitting, not the light output — a B22 lamp can be incandescent, halogen, CFL or LED. For which technologies you can still buy and how dimming works, see lamp types & dimming.
Tap any orange cap code below to see a picture of that lamp.
Bayonet cap (standard)
Push in and twist a quarter turn clockwise
Where you'll find it: The traditional UK domestic lamp cap. Pendants, ceiling roses, table and floor lamps in older and mid-age homes.
Watch out for: Two pins on the side of the metal base locate into slots in the holder. If the lamp will not seat, check the two spring-loaded contacts inside the holder are not sunk or blackened — that points to arcing and a worn holder.
Small bayonet cap (mini BC)
Push and twist, smaller diameter
Where you'll find it: Wall lights, chandeliers, bedside and decorative fittings, older fridge and cooker-hood lamps.
Watch out for: Easy to confuse with B22 when buying — measure the metal cap: B22 is 22 mm across, B15 is 15 mm. Often supplied as candle, golfball or pygmy shapes.
Edison screw (standard)
Screw in clockwise until firm — do not overtighten
Where you'll find it: The most common cap on modern and imported fittings, smart bulbs, filament decorative lamps and most new pendants.
Watch out for: The centre contact in the holder is spring-loaded; if a lamp flickers, isolate first and check the contact has not been flattened by overtightening. Never force a screw lamp that binds — cross-threading damages the holder.
Small Edison screw (mini ES)
Screw in clockwise
Where you'll find it: Chandeliers, wall brackets, candle lamps, cooker hoods, oven lamps and many table lamps.
Watch out for: Oven and appliance versions are special heat-rated lamps — a standard E14 LED will fail or distort inside an oven. Always replace appliance lamps with the manufacturer's specified type.
Miniature Edison screw
Screw in clockwise
Where you'll find it: Torches, older Christmas light sets, appliance indicator lamps and some emergency signage.
Watch out for: Low-voltage in almost all domestic uses; check the voltage marked on the lamp and holder before replacing.
Mains-voltage twist-lock spotlight
Push up, twist a quarter turn clockwise, release
Where you'll find it: Kitchen, bathroom and hallway downlights in most homes built or refurbished since the 2000s. Operates directly at 230 V.
Watch out for: Two thick pins with wider heads. No transformer or driver is involved. Because it is mains voltage, isolate the circuit before removing — the internal contacts are reachable with a fingertip once the lamp is out. Recessed GU10 downlights often sit flush in the ceiling with no rim to grip: a rubber lamp suction (sucker) tool, lightly moistened and pressed firmly onto the cool lamp face, gives enough grip to push up and twist the lamp free without cracking it.
Low-voltage push-fit spotlight
Push straight in — two thin pins, no twist
Where you'll find it: Older downlight installations, display and cabinet lighting. Runs at 12 V through a transformer or LED driver.
Watch out for: Looks similar to GU10 but has two thin straight pins. Never force a GU10 into an MR16 holder or vice versa. When swapping halogen MR16 for LED, the existing wire-wound or electronic transformer often will not run the much lower LED load — a dedicated LED driver is usually needed.
Miniature low-voltage spotlight
Push-fit, two thin pins, 4 mm apart
Where you'll find it: Cabinet, plinth, shelf and display lighting.
Watch out for: Very small reflector lamps, typically 12 V. Check the driver output before changing lamp type.
Capsule (mains voltage)
Push straight in — two looped wire pins
Where you'll find it: Wall lights, small pendants, bathroom mirror lights, cooker hoods and modern chandeliers.
Watch out for: Mains voltage 230 V, and the glass capsule gets extremely hot in halogen form. Handle with a cloth — skin oils shorten halogen lamp life and can cause the glass to fail. LED G9 replacements run far cooler but need to physically fit the enclosure.
Miniature capsule (low voltage)
Push-fit, two straight pins
Where you'll find it: Cabinet lights, cooker hoods, plinth lighting, some desk lamps.
Watch out for: 12 V through a driver or transformer. Same handling rule as G9 for halogen versions.
Flat twist-lock cabinet lamp
Insert and twist to lock
Where you'll find it: Slimline under-cabinet and plinth fittings.
Watch out for: Shallow puck-shaped lamp designed for fittings with almost no depth. Mains voltage.
Fluorescent and compact fluorescent tubes
Pin-in or twist-and-lock, depending on type
Where you'll find it: Garages, utility rooms, older kitchens, bathroom bulkheads, under-cabinet strips and 2D bulkhead fittings.
Watch out for: Fluorescent tubes contain a small amount of mercury and must not go in household waste — take them to a recycling centre. Repeated flickering or blackened tube ends usually means the starter, ballast or tube has reached end of life. Many old fluorescent fittings are best replaced with a modern LED batten.
Linear double-ended
Spring-load one end, drop into the other contact
Where you'll find it: Uplighters, security floodlights and some older wall washers.
Watch out for: Halogen versions run extremely hot and must be fully cool before touching. Handle by the ceramic ends only, never the quartz tube.
GU10 downlights: the suction (sucker) tool
Many recessed GU10 downlights sit flush in the ceiling with no rim to grip, and LED lamps with smooth glass or plastic faces give your fingers nothing to hold. A rubber lamp suction tool solves it: let the lamp go completely cold, lightly moisten the rubber cup with a damp cloth, press it firmly and squarely against the centre of the lamp face until it grips, then push up and twist a quarter turn anticlockwise to release the lamp. Push and twist the opposite way to fit the new one, then peel the cup off sideways.
If the cup keeps slipping, the lamp face is greasy or dusty — wipe it clean and dry first. Never pull straight down on a GU10 without twisting, never lever with a screwdriver, and stop immediately if the whole fitting starts to come out of the ceiling. Isolate the lighting circuit at the consumer unit before starting: GU10 holders are at 230 V and the contacts are reachable once the lamp is out.
Choosing the right replacement
- Cap type — must match exactly. Adaptors exist but add another connection that can loosen and overheat; a matching lamp is always better.
- Voltage — GU10, G9, B22, E27, E14 and GX53 are normally 230 V mains. MR16 (GU5.3), G4 and MR11 (GU4) are normally 12 V through a transformer or driver.
- Wattage — never exceed the maximum marked on the luminaire. LED equivalence is quoted in lumens: roughly 800 lm replaces an old 60 W lamp, 1,500 lm a 100 W lamp.
- Colour temperature — 2700 K warm white for living rooms and bedrooms, 3000 K for kitchens and bathrooms, 4000 K neutral for garages, utility rooms and workshops. Mixing temperatures in one room looks wrong.
- Dimmable or not — a non-dimmable LED on a dimmer will flicker, buzz or fail early. Trailing-edge dimmers suit LEDs; old leading-edge dimmers often do not, and most have a minimum load the LEDs cannot meet.
- Enclosed fittings — sealed bulkheads, bathroom fittings and glass-covered pendants trap heat around the LED driver. Use lamps explicitly marked "suitable for enclosed luminaires".
- Bathrooms and outdoors — the fitting must carry the right IP rating for its zone. See bathroom zones and garden & outdoor safety.
Never do this
- ✕Never change a lamp while standing in a bath, shower tray, or with wet hands or wet feet.
- ✕Never remove a lamp that has broken in the holder without isolating the circuit at the consumer unit first.
- ✕Never fit a lamp above the maximum wattage marked on the fitting, or a non-enclosed-rated LED into a sealed fitting.
- ✕Never force a GU10 into an MR16 holder, or a B22 into a B15 — the cap types are not interchangeable.
- ✕Never use a metal implement to lever a stuck lamp out of a live or un-isolated fitting.
- ✕Never ignore a warm ceiling rose, a scorched holder, a smell of hot plastic or a lamp that keeps blowing.
Disposal
Fluorescent tubes and compact fluorescent lamps contain mercury and must go to a household recycling centre or retailer take-back scheme, never in the general waste bin. LED and halogen lamps are not classified as hazardous but should still be recycled where facilities exist. Wrap broken glass before disposal.
When to stop and call an electrician
- →A lamp blows repeatedly in the same fitting, or blows the circuit breaker or RCD when switched on.
- →The lampholder, ceiling rose or downlight ring is discoloured, brittle, cracked or smells hot.
- →A lamp has broken off and the base is stuck in the holder and will not release.
- →Downlights are fitted in an insulated or fire-rated ceiling and you are unsure whether the fitting is fire-rated or covered by insulation.
- →The fitting is in a bathroom zone, above a shower, or outdoors and shows any sign of water ingress or corrosion.
- →Lights flicker across more than one room, or dim when other appliances start — this can indicate a loose supply connection.
- →You want halogen downlights converting to LED, or a fluorescent fitting replacing with an LED batten.
Common questions
Do I need to turn the power off to change a bulb?
Yes. Switch the light off at the wall switch and, wherever practical, switch off the lighting circuit at the consumer unit and lock or label it off. A wall switch may only break the line conductor, and in older or incorrectly wired installations the lampholder can remain live even when switched off.
How do you get a flush GU10 downlight bulb out?
Isolate the lighting circuit and let the lamp go completely cold. Recessed GU10 lamps often sit flush with no rim to grip, so use a rubber lamp suction (sucker) tool: moisten the rubber cup slightly, press it firmly and squarely onto the centre of the clean, dry lamp face, then push up and twist a quarter turn anticlockwise. Never lever a GU10 out with a screwdriver, and stop if the whole fitting starts pulling out of the ceiling.
Why do my LED bulbs keep failing so quickly?
The usual causes are an incompatible trailing-edge dimmer, enclosed or insulated fittings that trap heat around the driver, poor-quality lamps, or loose lampholder contacts causing arcing. Persistent early failures in one fitting only usually point to a fitting or connection fault, not the lamps.
Can I put an LED bulb into any existing fitting?
In most cases yes, provided the cap type matches, the lamp physically fits, and any dimmer is LED-compatible. Low-voltage MR16 fittings need a driver rated for the low load of LEDs, and enclosed fittings need lamps specifically marked as suitable for enclosed luminaires.
What do I do if a bulb breaks in the holder?
Isolate the circuit at the consumer unit first — not just the wall switch. Wear gloves and eye protection, and remove the remaining base with insulated pliers or a purpose-made extractor. If the holder is damaged, scorched or the lamp will not release, stop and call an electrician.
Why is the lampholder or ceiling rose discoloured?
Browning, blistering or a smell of hot plastic indicates overheating — usually from an over-wattage lamp, a loose terminal or a failing lampholder. Stop using the fitting, isolate the circuit and have the fitting and its terminations inspected by a qualified electrician.
Disclaimer — no liability
This guide is provided for general education only and is not a substitute for training, inspection or professional advice. Any work must be carried out safely, with the circuit isolated, and in accordance with BS 7671:2018+A4:2026, the manufacturer's instructions and the specific conditions of the installation.
All Cabling© Limited accepts no liability whatsoever for any loss, damage, injury, cost or non-compliance arising directly or indirectly from use of, or reliance on, this guide. If you are in any doubt, stop and call a qualified electrician.