How to Install LED Strip Lights

Plan the installation first

The most common LED strip installation mistakes happen at the planning stage. A few minutes before you buy anything will save hours of remedial work.

Measure the total run length — every section of strip, including corners, cove drops, and gaps. Add 10% as a buffer for cutting losses.

Decide on feed points — the maximum recommended single-feed run for Lumily LED 24V strip is 5 metres. If your total run is longer, plan to feed from both ends, add a mid-feed point, or use multiple drivers.

Calculate the driver size — wattage per metre × total run length, then add 25% headroom. Round up to the next standard driver size.

Do you need an electrician?

LED strip lights are low-voltage products (24V DC) — not classified as fixed electrical installations. The strip, driver, and any low-voltage wiring can be installed by a competent non-electrician.

However, the mains connection to the driver falls under Part P of the Building Regulations in England and Wales. If in any doubt, have the mains connection made by a qualified electrician. The low-voltage side of the installation — driver to strip, strip mounting, profile fitting — is straightforward for a competent DIYer.

Cut the strip to length

LED strips can only be cut at the marked cut points — the small copper pads printed at regular intervals along the strip, usually every 25mm, 50mm, or 100mm depending on the LED density. Use sharp scissors and cut cleanly through the centre of the copper pad.

Prepare and mount the profile

Measure and cut the aluminium profile to length using a fine-tooth hacksaw or mitre saw. Deburr the cut ends with a file to remove sharp edges. Clean the mounting surface with isopropyl alcohol and allow to dry.

For permanent installations — under-cabinet strips, ceiling coves, commercial installations — use mechanical fixings (small screws through the base of the profile) in addition to adhesive. The 3M adhesive aids positioning; the screws are what holds the installation long-term.

Peel and lay the strip

Peel back the paper liner from the 3M adhesive a section at a time — do not peel the full length at once or the adhesive will pick up dust. Lay the strip carefully into the channel of the profile, pressing it flat along its full length. Make sure the strip sits centred in the channel — off-centre strips produce uneven light distribution through the diffuser.

Make the connections

Strip to driver — use two-core cable from the driver's output terminals to the start of your strip. The strip PCB is marked + and −. Reverse polarity will result in no light but will not damage the strip — if nothing lights up, check polarity first.

Strip to strip — use a clip connector designed for your strip width. Open the clip, insert the strip with the copper pads aligned to the connector pins, and close firmly. Give the strip a gentle tug to confirm it is secure.

Connect to the driver — the driver has mains input terminals (Live, Neutral, Earth) and DC output terminals (+ and −). The mains input connection requires a qualified electrician if connecting to a fixed mains circuit.

Test before closing up, then fit diffuser and end caps

Power up the installation and check every section lights evenly before fitting diffusers or doing any finishing work. Look for:

• Any sections that do not light — likely a connector not seated correctly
• Dimmer sections at the far end of a run — voltage drop; feed the other end or add a mid-feed
• Colour inconsistency across the run — check for different batches of strip

Once everything checks out, clip the diffuser into the profile channel and fit the end caps to seal the profile ends for a clean, professional finish.