How do I fit under-cabinet lighting in a kitchen?

Under-cabinet lighting is the single biggest improvement most kitchens can have for the money, because the person cooking stands between the ceiling light and the worktop and works in their own shadow. The job is straightforward at plug-in level and stops being a DIY job the moment a new circuit or a wall switch is involved.

Safety

What you'll need

• Plug-in LED under-cabinet kit with a driver
• Screwdriver and a bradawl
• Cable clips or self-adhesive trunking
• Tape measure
• Torch (optional)

Step by step

1. Decide what you are lighting.Worktop task lighting is the point. Decorative glow inside glass cabinets or above the units is a different fitting and a different position. Do not try to make one fitting do both.
2. Choose the fitting type.Continuous LED strip gives the most even light and shows fewest reflections in a gloss splashback. Bar or batten fittings are easier to fix and to replace. Puck lights give pools of light and visible scallops on the splashback, which some people like and some find fussy.
3. Check the colour temperature before buying.Around 3000K reads as warm white and suits most kitchens; 4000K is neutral and better for detailed work; anything above about 5000K looks clinical in a domestic kitchen. Look for a high colour rendering figure if you care what food looks like.
4. Position the fitting towards the front of the unit's underside.This is the whole trick. A light at the back of the underside throws its beam up the splashback and into your eyes when you look up. A light near the front edge throws it down onto the worktop where you are working.
5. Dry-fit and switch on before fixing anything.Hold the fitting in place, plug it in, and look at the worktop and at the splashback from where you actually stand. Reflections in a gloss splashback or in a glass upstand are much easier to solve now than after drilling.
6. Fix the fitting with short screws.Short — the underside of a wall unit is 18mm and you do not want a screw appearing inside the cupboard. Check the length against the board before driving. Adhesive-backed strips need a degreased surface or they fall off within a month in a kitchen.
7. Plan the cable route before you fix the lights.Up the back of the units, along the top of the wall units behind the cornice, or in self-adhesive trunking on the underside where the pelmet will hide it. Never across a worktop and never where a future screw could reach it.
8. Keep the driver accessible.The low-voltage driver is the part most likely to fail. Mount it inside a cupboard or on top of the wall units where it can be reached, not sealed inside a boxed-in void.
9. Plug into an existing socket, or stop here.A plug-in system into an existing socket is where the DIY boundary sits. If you want a wall switch, a fused connection unit, or the driver wired into the fixed wiring, that is notifiable electrical work in a kitchen and needs an electrician's certificate.
10. Fit the pelmet afterwards.If you are fitting pelmet, the lights and the cable go in first and the pelmet closes it all up. That is what the pelmet is for.

Tips

• Sensor switches that respond to a hand wave under the cabinet are genuinely useful with wet or floury hands, and plug-in versions exist that need no fixed wiring.
• In a kitchen with a gloss splashback, a continuous strip fitting reflects as a single line and a row of pucks reflects as a row of bright dots. Worth thinking about before buying.
• If the driver hums or the lights flicker on a dimmer, the dimmer and the driver are incompatible. Most plug-in LED kits are not dimmable at all and should be run at full output.
• Measure the total run and check the driver's wattage covers it. Adding a second strip to a driver that is already at capacity is a common cause of dim or flickering light.

Common mistakes

• Fixing the light at the back of the cupboard underside — The beam goes up the wall and straight into your eyes when you stand at the worktop. The whole benefit is lost, and the glare is worse than the original shadow.
• Hiding the driver inside a sealed void — It is the component most likely to fail, and reaching it later means dismantling the thing you built around it.
• Extending a kitchen's fixed wiring for the lights — New circuits and alterations to fixed wiring in a kitchen are notifiable building work in England and Wales. Doing it yourself leaves uncertified work that shows up at sale.

Questions people ask