Indirect lighting for a new home

Every indirect light line needs a 230 V supply to its driver. If the supply is not drawn, the electrician does not install it, and the strip is left without power. A normal room needs 1-2 supplies (spotlights + indirect light). Large perimeters need conduit/cable from both ends to the same driver.

Good answer: ”I mark the position of every driver and its supply. Tell me where the structures are, and I will place the drivers at the nearest serviceable point.”

Three options, three different cabling layouts. Inside the box the driver is close to the strip but needs an access hatch. On top of a cabinet it is easy to replace but the cable has to be run there. In a technical room everything is in one place, but the 24 V cable can get long and the voltage drop increases.

Good answer: ”On top of a cabinet or in a technical room if the distance to the strip is under 5 metres. Otherwise inside the box, and I draw the access hatch position on the boarding drawing.”

The access hatch is a building detail, not an electrical detail – it easily falls between two contractors. If the electrical designer places the driver in the box but nobody draws the hatch on the boarding drawing, the driver gets plastered in.

Good answer: ”I mark the hatch on the electrical drawing at a minimum of 300 × 300 mm, and record in the contract scope that the boarder builds it.”

The traditional way: one switch, one light, on or off. Scene control: one ”Evening” button dims the general light to 30 percent, switches on the kickboard light and turns off the kitchen task light. Scenes need a system – either wireless Zigbee or wired DALI. Traditional switch control needs nothing, but it only gives dimming for one group with dimmable drivers.

Good answer: ”Scene control. I will cable it so that it works, and we choose the system next.”

Both do scenes and dimming, but they are cabled completely differently. Zigbee is wireless: the driver gets a 230 V supply and has a radio built in, the buttons are battery-powered and no control cable is needed – no cable to wall boxes! Cheaper to cable, and the button position can be decided later.

DALI is wired: in addition to the supply, a two-wire control bus is run to every driver, and the buttons are connected to the same bus. More expensive to cable but does not depend on radio, and it is the standard in public spaces.

For a home Zigbee is almost always enough – DALI makes sense if the house already has a DALI system for other lights, or if everything is to be hard-wired.

Good answer: ”Zigbee, unless a DALI bus is going into the house anyway. If DALI, I draw the bus to all drivers now – it cannot be added afterwards.”

Zigbee needs no control cable for wall switches, but that does not mean nothing goes on the electrical plan. Every driver still needs a 230 V supply and a position. And the gateway needs a socket and a network connection; it can be installed anywhere in the house with Ethernet. The app finds the gateway and its lights over the local network (Wi-Fi).

Good answer: ”A supply and position for every driver, switch boxes for any buttons where batteries are not wanted, and a socket for the gateway in a central location.”

A control group is a set of lights that behave together. If the living room’s indirect light and the kickboard light are in the same group, they cannot be dimmed separately. Usually at least two groups per living space are wanted: general light and mood light. In Zigbee the groups are programmable, i.e. changeable afterwards. In DALI they are also programmable, but in traditional switch control the group is whatever is wired to the same switch – and that is fixed after boarding.

Good answer: ”At least two groups per living space. With Zigbee the groups can be changed later – but there has to be one driver per group, so the number is decided now.”

With a 24 V strip, voltage drop is usually only a minor issue if the access hatch is near the room, so runs from driver to light are 1-5 metres. For cables over 10 metres, 1.0-1.5 mm² is recommended. For longer runs (everything installed at the distribution board), the solution is a thicker cable, 2.5 mm². The electrical designer calculates this if the distances are known.

Good answer: ”I keep the 24 V cables under 5 metres or size the cross-section for the loss. Tell me the driver positions and strip lengths.”

In a strip over 7-8 metres the far end dims even with a thick cable, because the loss happens inside the strip. The solution is to feed from both ends, which means two cables from the driver, or the strip is cut in the middle and fed from two drivers. This must be known before the cables are pulled. The most common arrangement is one driver with a feed from both ends to the same driver.

Good answer: ”Yes, and I need to know which strips are over 7-8 metres.”

Every joint needs space or a box that remains accessible IF the joint is made at the end of the LED strip. A large hole next to or under the LED profile spoils the result. The best solution is to run a 16-22 mm conduit from the driver to the end of the LED profile, so the cable can be fed in one piece all the way to the driver without joints.

Good answer: ”I place the boxes and joints behind access hatches or furniture, and mark them on the joinery drawing.”

A Zigbee button is battery-powered and can be fixed anywhere – no cable. If a normal-looking wall button matching the other switches is wanted, LedStore’s Zigbee buttons fit 55 mm switch ranges such as EXXACT, INTRO and JUNG. The button itself needs no box behind it, so it can be added to the other switches simply by enlarging the frame by one (e.g. 3-gang → 4-gang). A DALI button always needs the bus cable and therefore a box behind it.

Good answer: ”With Zigbee we choose a button that fits, e.g., the EXXACT range. Battery buttons basically need no box behind them.”

The hallway, corridor, WC and utility room benefit from a motion sensor. A Zigbee sensor is battery-powered and wireless. A conventional sensor needs a supply and connection ahead of the driver.

Good answer: ”Zigbee sensors in the hallway and corridor, no cabling. If conventional, a supply to the sensor and it connects ahead of the driver.”

The electrical designer does not draw structures – that is the architect’s or structural designer’s job (and often the lighting designer’s!). But if nobody takes responsibility, the box is built to the wrong depth or there is no room left for the profile.

Good answer: ”I ask for the construction drawings and mark the electrical points on them. The structure dimensions come from the architect – make sure they have them.”

The bathroom and sauna are wet rooms. The driver must not be in bathroom zones 0-2, and in the sauna the strip may only be under the benches below 60 degrees. The driver is placed outside the bathroom and the 24 V cable is brought in.

Good answer: ”Drivers outside the wet rooms, IP65 strip, and the sauna strip under the benches. I mark the zones on the electrical drawing.”

If the budget does not stretch now, a provision alone is cheap: a supply for the driver and an empty conduit to the strip position. The structure, i.e. the box, still has to be built now, because it cannot be added afterwards. The provision keeps the option open – without it, retrofitting is limited to surface profiles.

Good answer: ”Yes. I run the supply and conduit, and mark them on the drawing as a provision.”