LED Strip Light Installation

It looks simple, but the result depends on doing things in the right order and measuring carefully. An electrician usually works like this:

1. Agree with you on where the line of light goes, its length, the colour of light and how it will be switched
2. Measure the run and cut the aluminium profile to length, mitring the corners where needed
3. Fix the profile with screws, clips or adhesive, and for a recessed profile, rout a groove first
4. Degrease the inside of the profile and stick in the LED strip, cutting it only at the marked points
5. Connect the supply cable by soldering or with a connector and insulate the joint
6. Place the driver and controller where they can be reached later
7. Connect the driver to the mains (230 V in most of Europe), which is a job for a qualified electrician
8. Clip on the diffuser, fit the end caps and test the light along the whole length

Why does the strip go into a profile rather than straight onto the cupboard? The aluminium works as a heat sink. A strip that does not overheat keeps its brightness and colour for longer.

Type of profile

• Surface profile: screwed or stuck onto a flat surface, ideal under kitchen units and on shelves
• Corner profile: shines at roughly 45 degrees, works well in the corner of a cabinet or beside a mirror
• Recessed profile: sits in a groove in furniture or plasterboard and ends up flush with the surface
• Ceiling and stair profiles: special shapes for indirect light or for fitting into stair treads

Diffuser

A clear cover lets more light through, but you can see the individual LEDs as dots. A milky (opal) diffuser softens the light and gives a continuous line. With a glossy kitchen worktop, an opal cover is almost always worth it, because otherwise the dots reflect in the surface.

LED strip

• 12 V or 24 V: for longer runs 24 V is the better choice, as it loses less brightness towards the far end
• Colour of light: usually warm white of around 2,700 to 3,000 K for living rooms and bedrooms, and neutral white of around 4,000 K for kitchens and bathrooms
• LED density: more LEDs per metre give more even light, and COB strips look continuous even without a thick diffuser
• Single colour, CCT or RGB: CCT changes the shade of white and RGB changes colour, and both need a controller and extra wires
• IP rating: bathrooms and outdoor areas need a strip with higher protection, usually IP65 or above

An LED strip cannot run straight from a socket. It needs a driver (power supply) that brings the voltage down to 12 or 24 V. The driver must match the voltage of the strip and have some spare capacity. In practice, about a fifth more power than the strip draws is a sensible margin. A driver chosen right at its limit runs hot, and the strip then flickers or fails early.

Where the driver goes matters too. It should never be plastered in or sealed into a ceiling with no way to reach it. Drivers often wear out after some years and need replacing. If it sits in a cupboard, above an access hatch or in a box, the swap is quick.

You can switch the strip with an ordinary wall switch, a touch or motion sensor built into the profile, a remote control or an app on your phone. Decide on this before the work starts, because it determines how many wires are needed and where they have to run.

Connecting the driver to the fixed mains wiring, adding a new box, outlet or switch is work for a qualified electrician. After any work on the fixed installation, ask for a certificate or written confirmation of the work, as required by your local wiring regulations. Larger changes may also need inspection and testing. If you live in a block of flats and the work would touch shared wiring, check with the building management or owners' association first.

The amount of work, and so the final cost, depends on the situation:

• Surface mounting is quicker than a recessed profile, which needs a routed groove
• Straight runs are simpler than lines with corners, where the profile must be mitred precisely and the strip linked
• Length and number of sections matter, because every break means another joint and more cabling
• Cable routing is easy if a supply point is already waiting in the wall or furniture, and harder when the cable has to be hidden afterwards
• Controls: a plain switch is less work than an RGB or smart controller that needs setting up
• Environment: bathrooms and outdoor areas need every joint sealed
• Access: ceilings and tall stairwells need a ladder or scaffold tower

• A strip stuck into a profile that was not degreased comes loose over time and overheats at that spot
• A strip cut away from the marked points leaves a dead section at the end
• An undersized driver with no margin causes flicker and shortens the life of the whole set-up
• A long run fed from one end only is visibly darker at the far end, and feeding from both ends or in sections solves this
• A strip bent sharply round a corner has a broken track, so corners need a connector or a linking cable
• A driver with no access means taking apart furniture or a ceiling when it fails
• In bathrooms, the IP rating and sealing of joints are underestimated, which leads to corrosion or short circuits

When the job is handed over, it is worth spending a few minutes on this list:

• The strip lights evenly along its whole length and the end is no darker than the start
• With a diffuser, no individual LED dots are visible, if that was agreed
• The profile is firmly fixed and straight, and the corner joints are neat
• The end caps are fitted and the cover sits flat everywhere
• The strip does not flicker, including when dimmed if it is dimmable
• The switch, sensor or app works and you know how to use it
• The driver is accessible and not hot to the touch after the light has been on for a while
• The colour of light matches what was agreed and is the same across all sections
• If mains wiring was involved, you have the certificate or written confirmation of the electrical work