Installing recessed spotlights: wiring and installation step by step

Recessed spotlights provide modern, uniform lighting, ideal in a kitchen, hallway or living room. Contrary to popular belief, installing them yourself is within reach of a good DIYer, provided you scrupulously respect the electrical safety rules and the NF C 15-100 standard. This guide explains how to choose the right gear, carry out the parallel wiring and fit your spotlights in a plasterboard or drywall ceiling.

The necessary gear before starting

• Recessed LED spotlights compatible with the depth of your ceiling (generally 30 to 90 mm of recessing depth)
• A 3G1.5 mm² electrical cable (three conductors: live, neutral, earth) with a cross-section suited to the installed power
• Recessed boxes (68 mm recessed boxes) to connect the cables together, mandatory in a partition
• A connector block or Wago connectors for the connections, with an insulated screwdriver and a wire stripper
• A non-contact voltage tester or a multimeter, as well as safety glasses and a dust mask
• A 68 mm hole saw or a drywall saw suited to the diameter of your spotlights, and a drill

How many spotlights to install and where to place them?

Generally plan one LED spotlight every 80 to 120 cm in a living room, i.e. about 6 to 8 spotlights for a 15 m² room. The spacing between two spotlights must remain less than 1.5 times their height above the floor to avoid dark areas. Mark the position of each spotlight on the ceiling with a pencil and a tape measure, checking that no obstacle (joist, duct, cable) is above the drilling point.

Switching off the power and preparing the circuit

1. Switch off the lighting circuit breaker at the consumer unit and check the absence of voltage with a non-contact tester on the outgoing wire
2. Determine the starting point of the circuit: the simplest is to start from the box of an existing light or a dedicated junction box
3. Run the 3G1.5 mm² cable from the source to the first spotlight, then branch in parallel to each following spotlight (each spotlight receives live, neutral and earth)
4. If the ceiling is accessible from the loft, route the cables overhead; otherwise, run the cables through the ceiling slabs before drilling

Drilling and fitting the spotlights

1. Drill a 68 mm hole (or the diameter stated on the packaging) at each marked position, holding the drill perfectly perpendicular to the ceiling
2. Pass the cable through the drilled hole and leave about 20 cm of wire protruding to work comfortably
3. Connect each spotlight to the circuit: connect the live (red or brown) on terminal L, the neutral (blue) on terminal N and the earth (yellow-green) if your spotlight is fitted with one
4. Use Wago connectors or connector blocks in a recessed box for each connection, never bare twisted wires
5. Recess the spotlight into the ceiling: the spring clips hold it automatically, without screws or adhesive
6. Once all the spotlights are fitted, restore the circuit breaker and test the lighting

Parallel wiring explained simply

Each spotlight must be wired in parallel on the same circuit: the live from the source arrives at a first spotlight, then goes on to the next, and so on. This guarantees that each spotlight receives the same 230 V voltage and that the failure of one spotlight does not switch off the others. Never wire spotlights in series, because the voltage would be divided and the brightness would collapse. If you install more than 8 spotlights or exceed 10 A on the circuit, add a dedicated 10 A circuit breaker.

What power and colour temperature to choose?

For a comfortable result, allow about 300 to 400 lumens per spotlight for a living room, i.e. LED spotlights of 5 to 7 W each. The colour temperature, expressed in kelvins (K), defines the atmosphere: 2700 K for a warm, cosy light, 3000 K for a neutral warm white and 4000 K for a cool white better suited to work areas like the kitchen. LED spotlights have a stated lifespan of 25,000 to 50,000 hours, i.e. years of use without changing a bulb. Prefer spotlights with a suitable protection rating if you install them in a bathroom, respecting the safety zones of the NF C 15-100 standard.

The mistakes to avoid

• Working without switching off the power or without checking the absence of voltage with a tester
• Recessing halogen spotlights in an insulated partition without respecting the minimum safety distance from the insulation (fire risk)
• Wiring the spotlights in series: the lighting would be very weak and a single fault would switch everything off
• Using cables of the wrong cross-section (1.5 mm² minimum) for the installed power
• Making bare connections without a recessed box or an approved connector

Your recessed spotlights are fitted and working. If the final test reveals a spotlight that does not light up, first check the connection in its box, then the contact of the springs. For more complex work (changing the consumer unit, adding a circuit), call in a certified electrician, because some operations remain reserved for professionals. A clean, compliant installation guarantees you durable and safe lighting.