- Power supply: 12 or 230 V?
- Constraints to be respected
- At each piece its lighting
- Create the opening in the false ceiling
- Connect the power supply of the luminaire
- Embed the spot
- Install the lamp
- Practical tips for installing spots
- Recessed spots: mains or low voltage?
- Malfunction of very low voltage spots
The installation of spots in a plasterboard false ceiling provides a warm atmosphere. This is a fairly simple operation that requires however to be executed with precision.
The distribution and the number of spots depends on several factors: height under ceiling, size of the room and power of the bulbs. It is necessary to count 50 W / m2 on average, which corresponds to approximately 300 lumen / m2 (a concept increasingly used with low consumption lamps and leds).
Power supply: 12 or 230 V?
The type of lamp (more commonly known as "bulb *") chosen determines the installation and supply mode: - low voltage 230 V with "eco" halogen spotlights, with LEDs or, rarer, compact fluorescents; - very low voltage ** 12 V, also with halogen spotlights or LED bulbs. In the first case, the power supply is made by simple connection to the network, via a circuit "lighting". In the second, the bulbs are powered via a transformer lowering the voltage from 230 V to 12 V. The latter should normally remain accessible, and therefore be installed outside the false ceiling situation is rarely retained.
* What is commonly called "bulb" is actually a "lamp". The bulb refers only to the glass globe that protects the filament. What we call "lamp" is actually a "fixture".
** What we call "low voltage" is actually the "very low voltage safety" (SELV). It designates lamps of 6, 12 and 24 volts. Low voltage is anything less than 1,000 volts.
Constraints to be respected
Certain constraints and regulatory provisions must be respected before any connection: the 230/12 V transformer must be placed in a sufficiently ventilated space to evacuate the heat it generates and more than 10 cm and less than 3 m from the first spot of the 'installation.
At each piece its lighting
We generally favor a 230 V power supply in living rooms and, for safety reasons, at very low voltage (12 V) in damp rooms such as kitchens and bathrooms. In this last room in particular, the transformer must be placed out of the "volume 2" (the NFC 15-100 standard defines 4 so-called security volumes): that is to say at 60 cm minimum of the sanitary installations such as the bath and shower. Note that the standard NFC 15-100 sets design rules, realization and maintenance of installations low voltage electric. It is regularly updated to take into account technological developments and security requirements.
Create the opening in the false ceiling
- Determine the location of the spot on the ceiling and drill with the hole saw an opening with the recommended diameter (the model installed here imposes a drilling of 75 mm).
- Complete the drilling by adjusting the opening to the file.
- It is preferable that the nesting offers a slight resistance that keeps the spot well to offer neither play nor floating.
Connect the power supply of the luminaire
- Turn off the electricity and pull the light line above the ceiling.
- Strip the blue (neutral) and brown strands.
- This spot is class II, the grounding is not useful.
- Connect the wires to the luminaire connection box after unscrewing the cover.
- Screw it back to secure the two power wires.
Embed the spot
- Fix the flat tab of the connection box in the lateral notch of the metal part of the spot by blocking the screw, then raise the spring-loaded tabs.
- Engage the assembly in the ceiling opening.
- Push all the way down: the tabs tilt and come into place under pressure, holding the metal part of the spot.
Install the lamp
- Push the bulb into the socket by screwing it a quarter of a turn, its two studs inserted into the two notches of the porcelain.
- Check that it is securely fastened.
- Push the bulb back into the housing of its housing and install the locking circlip to prevent it from going down.
- Flip the moving part to direct the light as you like.
Practical tips for installing spots
• Warning: it can heat up! Spotlights, especially when they are halogen, give off a lot of heat. They must be placed more than 10 cm from the "true" ceiling, more than 10 cm from a wall and at least 20 cm from each other.
• Presence of mineral wool: a false ceiling on metal lines and rails is normally surmounted by a layer of insulation. We then cover the socket of the spot with a ventilated protection, about twenty centimeters in diameter, to separate it from the insulation.
Recessed spots: mains or low voltage?
To embed spots in a plasterboard ceiling, what is the choice between very low voltage spots or spots in the area?
Christian Pessey's answer:
Ceiling recessed spotlights can be powered by either a 12V transformer, which is connected to the mains by a plug, or powered directly from 230V. Although many installers overcome this constraint, the transformer of very low voltage (12V) spots must not be placed in the doubling, which poses the problem of its arrangement near a power outlet. This is why it is better to choose spots powered by the sector (230V), controllable by a switch, via a junction box.
Malfunction of very low voltage spots
Recessed ceiling, my spots very low voltage (12 V) turn off and then turn on after a quarter of an hour, then it starts again. Where does this dysfunction come from?
Christian Pessey's answer:
Very low voltage spots are powered by a transformer which must, according to the standard, remain visible. But very often, it is embedded in the false ceiling to hide it. This may be your case. In this situation, the transformer heats, for lack of ventilation. For safety, the transformer's thermal circuit breaker cuts off its power supply, which only recovers when it has cooled down.