Switch off power, let fittings cool, then remove the bezel or clip and swap the matching lamp for a safe, like-for-like replacement.
Cabinet spotlights look neat, but lamp swaps can feel fiddly in tight spaces. This guide walks you through safe prep, quick identification of lamp types, and step-by-step swaps for the most common fittings found under and inside cupboards. You’ll also get a checklist for drivers and transformers, plus fixes for flicker and dim output.
Identify Your Fitting And Lamp Type
Before touching a fixture, cut power at the switch. If the unit is hard-wired and you’ll handle wiring or a driver box, isolate the circuit at the breaker. Let the trim cool fully. Then check the front: some trims twist, others use a thin spring ring, and a few hold a glass lens with a small metal clip.
Next, match the lamp. Cabinet units commonly use small bi-pin capsules (G4, G9), two-pin MR16/GU5.3 on 12V, push-and-twist GU10 on mains, or sealed LED modules. The table below maps the usual suspects.
| Lamp Type | Common Base | Supply/Notes |
|---|---|---|
| G4 Capsule | G4 bi-pin | 12V with driver/transformer |
| G9 Capsule | G9 loop pins | 230/120V direct in many fittings |
| MR16 | GU5.3 two-pin | 12V; needs compatible transformer/driver |
| GU10 | GU10 twist-lock | Mains voltage; no separate transformer |
| LED Module | Proprietary | Often non-removable; whole module swaps |
Safe Prep, Tools, And Access
Tools are simple: insulated gloves, a flat screwdriver, a clean cloth, and a step stool. Add a tester if you’ll expose wiring. Clear the worktop and place a towel below the area in case the lens or trim drops. Keep new lamps in their cartons until the moment you fit them, and avoid touching bare LED or halogen glass with fingers.
Cabinet Spotlight Bulb Replacement—Step By Step
G4 Or G9 Capsules
1) Power off. 2) Hold the trim with one hand. 3) Ease out the thin spring ring or lens. 4) Pull the capsule straight out; rock gently if snug. 5) Without touching the glass, push the new capsule fully home. 6) Refit lens/ring, then test.
MR16 (GU5.3) Two-Pin
1) Power off. 2) Remove bezel or ring. 3) Grip the reflector edge and pull down. 4) Note the two pins and any label that mentions 12V. 5) Push the new lamp onto the same two-pin socket. 6) If the lamp doesn’t light later or flickers, check the transformer section in this guide.
GU10 Twist-Lock
1) Power off. 2) Hold the trim. 3) Twist the lamp a quarter-turn anticlockwise and pull down. 4) Align the new lamp’s lugs, insert, then twist clockwise until it clicks. 5) Test.
Sealed LED Pucks Or Modules
Some under-cabinet pucks don’t take a separate lamp. The light engine and bezel come as a set with two small screws or a snap plate. If the unit has a driver box, you may find it inside the cabinet or above the run. Match voltage and wattage when ordering a like-for-like module.
Close Variation: Swapping Cupboard Downlight Lamps—What To Watch
Small fixtures leave little room for fingers, so method matters. Work slowly, keep a tray for tiny clips, and check the rating label inside the fitting. That label tells you maximum wattage and the supply type. Never exceed that figure. If the label lists 12V only, do not push in a mains lamp.
Halogen To LED: Simple Upgrade Paths
Many cupboards still run halogen capsules or MR16 reflectors. LED versions slot into the same caps in most cases and run far cooler. On GU10, upgrades are straightforward: just match beam angle and colour temperature. On MR16 and G4, the supply relies on a transformer or driver. Older electronic units expected a higher load from halogen; that mismatch can cause no-start or flicker with frugal LED lamps.
Two quick checks help: 1) Read the fine print on the small box or can marked “transformer,” “driver,” or “LED driver.” 2) Compare the listed minimum load to your new lamp’s wattage. If the minimum load is higher than the new lamp’s draw, move to a driver designed for LED.
Driver And Transformer Basics For Cupboard Spots
A low-voltage system keeps the lamp on 12V through a transformer or driver. In a SELV setup, the supply is electrically separated from mains and kept in an extra-low range even if a single fault occurs (IEC SELV definition). That’s why you’ll often see a small plastic box between the mains feed and each lamp string.
Common driver choices include older electronic transformers, modern constant-voltage LED drivers, and integrated drivers inside each lamp. Mismatch brings flicker or early shut-off. If you’re replacing multiple halogens with low-watt LED, a new driver with a low minimum load solves most hiccups.
Step-By-Step: Finding And Replacing A Hidden Driver
1) Switch off and isolate if you’ll handle wiring. 2) Follow the thin low-voltage cable from the fitting back into the cabinet void. 3) Look for a small box labelled 12V, CV, or “LED driver.” 4) Photograph labels for current, voltage, and polarity. 5) Order a like rating from a trusted brand. 6) Swap one-for-one, matching input and output pairs. 7) Keep cable runs neat, avoid crushing, and test.
Quick Tests Before You Call An Electrician
These simple checks resolve most faults after a lamp swap. If live parts are exposed, stop and book a pro.
| Symptom | Likely Cause | Fast Fix |
|---|---|---|
| Flicker on 12V | Old transformer needs higher load | Use LED-ready driver or add load |
| No light at all | Pins not fully seated or dead driver | Reseat lamp; test driver output |
| Only some lamps work | Parallel strings or loose push-fit | Firm up connectors; match drivers |
| Buzzing | Overloaded transformer | Lower wattage or new driver |
| Yellow tint | Warm CCT lamp fitted | Pick 3000–3500K for kitchens |
| Glare on worktop | Narrow beam angle | Choose 60–90° spread |
Safety Notes You Shouldn’t Skip
Switch off power before any work, wait for trims to cool, and keep one hand holding the bezel when removing rings. If a fixture shows damaged insulation, charring, or loose lampholders, stop. A licensed electrician can replace the fitting or re-terminate wiring safely.
If you use a ladder, set it on a firm surface and don’t overreach. Use a dry cloth on smooth glass lenses to avoid slips. LED and halogen glass marks easily; finger oils can shorten halogen life, so fit with gloves or tissue. For safe habits around household fixtures, see the ESFI indoor lighting tips.
Match The Cutout And Trim Size
Cabinet recesses vary. Some pucks sit in a 57–60 mm hole with spring wings; others surface-mount on a plate. When a trim is cracked or a module fails, measure the hole diameter and the lip before ordering parts. A perfect fit stops rattles and keeps light spill even on the worktop. If the new trim squeaks or feels loose, add the thin foam gasket that often ships in the box.
Dimmer And Control Compatibility
Legacy dimmers for halogen don’t always play nicely with LED. Symptoms include shimmer at low levels and drop-out near the bottom of the slider. Pick an LED-rated dimmer with a published load window that matches the total wattage of your under-cabinet set. If the lights share a plug-in driver, some makers offer inline dimmers on the low-voltage side; match polarity and follow the wiring diagram from the leaflet.
Test And Tidy Before You Close Up
Before you clip the lens back in, power up once to prove the lamp seats correctly, then power down and finish the re-fit. Tug each connector gently to check it’s home. Tuck spare cable in a gentle loop so the bezel can sit flat. Wipe fingerprints from lenses and trims, then restore power and run the lights for five minutes. A stable beam with no buzz or flicker means you’re done. Keep screws in cups.
Disposal And Recycling
Halogen, CFL, and many LED products qualify for recycling at local collection points. Keep old lamps in their cartons to avoid glass splinters, and never throw loose fragments in general waste. Many councils list drop-off sites on their websites; search your postcode and “light bulb recycling” to find a spot near you.
Retainer Styles And How To Release Them
Spring ring retainers sit in a groove. Slip a small flat blade into the notch, lever the ring forward, and catch it with your other hand. Wire clip retainers have two bent tabs; squeeze both toward the centre and lower the glass. Twist bezels line up on bayonet lugs; a short anticlockwise turn is enough. If a bezel won’t budge, check for a tiny grub screw on the side and back it out half a turn.
Buying Checklist For Perfect Matches
Write down five items before you order: base type, voltage, wattage, colour temperature, and beam angle. Add driver style for low-voltage sets. For task zones, a neutral white around 3000–3500K with a 60–90° beam gives clean pools across the counter. For a soft wash inside a glass cabinet, try wider beams and lower output. If a cabinet traps heat, pick lamps with metal heat sinks or integrated vents, and keep paper goods clear of trims.
Two Smart Upgrades While You’re There
Swap old switches for a small inline sensor or a dimmer rated for LED loads. Many pucks accept a plug-in driver with a motion or door switch lead, which makes night-time access pleasant without touching a control.
Sources And References
For safe working habits, see the Electrical Safety Foundation International tips on indoor fixtures, which stress turning power off before replacing bulbs and letting parts cool. For the idea of SELV and separated low-voltage supplies in domestic lighting, see the IEC glossary entry.