DALI (Digital Addressable Lighting Interface)
DALI (IEC 62386) is a wired lighting protocol that lets each fitting be addressed, dimmed and grouped on its own, unlike simple phase dimming.
What is DALI, and where does the standard come from?
DALI (digitálne adresovateľné osvetlenie in Slovak) is a wired control protocol for lighting, defined in the international standard IEC 62386. Each ballast or LED driver on the bus, called control gear, receives its own address, so a controller can dim one luminaire, a group of them or every fitting in the house. The control signal travels on a separate control pair, while the mains feed to each fitting stays live. The lighting industry developed the standard so that products from different manufacturers would share one language. The DALI Alliance now runs the DALI-2 certification programme, which tests products against the newer edition of the standard.
How does a DALI line carry commands and addresses?
A DALI line is a two-wire bus that does not care about polarity, so the wires can be swapped without damage. The controller sends short digital telegrams, and each piece of control gear responds only to its own address, to the groups it belongs to, or to a broadcast to all. A single line supports a limited number of addresses, so a large house needs several lines, each with its own power supply. Because the signal is digital, the controller can also query status, such as a lamp failure, when the gear supports it. Group membership is set during commissioning, which is why the lighting plan and the commissioning file must agree.
How is DALI different from phase dimming?
Phase dimming, known in Slovak as fázové stmievanie, cuts the mains waveform on a circuit, so every lamp on that circuit receives the same brightness. It works with a compatible dimmer and a dimmable driver, and it needs no extra cable. DALI replaces that single shared signal with addressed commands, so each fitting can be set on its own and one button can recall a lighting scene across many circuits. Phase dimming is simpler and cheaper for a few rooms, each on one circuit. DALI earns its cost when fittings need separate levels, when fault reporting matters, or when the same logic must repeat across the whole house.
How do DALI, KNX and wireless systems compare for a house?
No option is best in every case. The table compares the four approaches a family house usually considers. The cabling row matters most, because it decides what must be settled before the walls are closed.
| Feature | Phase dimming | DALI | KNX | Wireless |
|---|---|---|---|---|
| Extra control cable | None beyond mains | Yes, to each fitting | Yes, one shared bus | None |
| Individual fitting control | No, per circuit | Yes | Yes | Yes, per device |
| Scenes and groups | Limited | Built into the controller | Built into the controller | Depends on the hub |
| Covers shading and heating | No | No, lighting only | Yes | Partly |
| Retrofit into a finished house | Easy | Difficult | Difficult | Easy |
Wireless suits renovations and rented flats, but its costs are signal reliability, switch batteries in some models and dependence on a hub. KNX suits a whole-house installation planned from the start, where lighting is one trade on the same bus as shading and heating. DALI sits between the two: a dedicated lighting network that needs no building-wide design, but still needs cable before plastering. For the wider choice of devices and hubs, see the smart lighting control article.
What do DALI-2 and DT8 add for tunable white?
Tunable white means a fitting can move between warm and cool white. In DALI, this is handled by the DT8 device type, which covers colour control, so the driver must declare that device type to accept tunable commands. A plain dimmable driver only changes brightness and cannot shift colour temperature at all. DALI-2 is the second generation of the standard, and its certification programme checks that products behave consistently on the bus. When you specify fittings, ask for DALI-2 certification and DT8 by name, rather than relying on the word DALI printed on the packaging.
What cabling does DALI need before plastering?
Decide the control cable in the same drawing as the mains circuits, before the first fix is closed. A DALI line needs its own route from the controller to every fitting and every push-button position, so each ceiling point and wall box must have a path for the control pair. The table lists the decisions to settle first.
| Decision | What to settle before plastering |
|---|---|
| Bus lines | How many lines the house needs and where each one starts at the controller |
| Fitting positions | Every ceiling and wall point that gets a DALI address, including outdoor and staircase lights |
| Push-button positions | Which walls get DALI input devices, and whether they share a box with a mains switch |
| Cable route | A separate path for the control pair, kept apart from mains conductors as the installation standard requires |
| Record | An as-built plan with the bus route marked, so a later fault can be traced from the drawing |
Adding a control pair after plastering means chasing walls or running surface trunking, which costs more and looks worse. A wireless switch can be added later, but a DALI line cannot be added to a finished wall without the same work the first time. The electrician should label the cable at each box, and the commissioning file should list the address and group of each fitting.
Is DALI worth it for a family house?
DALI pays off where lighting logic is complex: many rooms with several fittings each, a living room that needs layered scenes, an outdoor zone with its own schedule, or a client who wants one button per activity throughout the house. It is harder to justify for a small house with a few circuits, where phase dimmers plus one or two wireless scene switches deliver most of the result. Remember that DALI covers lighting only. If shading, heating and ventilation also need automation, KNX may cover the whole building on one bus, and the lighting can join it through a gateway. The decision belongs in the interior lighting plan, drawn before the electrical layout is final.
What are the common misconceptions about DALI?
- DALI is not wireless. It needs a physical control pair, which is why it is a planning decision rather than an afterthought.
- A DALI-compatible driver is not automatically tunable. Colour control needs the DT8 device type.
- DALI does not remove the mains feed. Each driver still needs supply power, and the bus carries only control signals.
- Mixing brands works best with certified products. Uncertified gear may respond on the bus but misbehave in groups, scenes or fault reporting.
Frequently asked questions
- Can DALI be added to a house that is already built?
- Usually only with new cable, because every fitting needs a control pair routed back to the controller. Retrofits mean chasing walls or running surface trunking. For a finished house, wireless lighting control is the common alternative.
- Is DALI the same as KNX?
- No. DALI is a lighting-only network, while KNX is a whole-building bus that can also control shading, heating and ventilation. Both are wired, but the protocols differ, so a gateway is needed to link them.
- Do I need DT8 drivers for warm-to-cool white?
- Yes, if the fittings must change colour temperature, the driver has to declare the DT8 device type. A plain dimmable driver only changes brightness. Check the datasheet for DT8 and DALI-2 certification before ordering.
- Can DALI be controlled from a phone?
- Yes, through a gateway or a controller with an app interface. Choose a controller that keeps working locally without the internet, so the lights do not depend on a cloud service.
- Do ordinary wall switches work with DALI?
- A conventional mains switch cuts power to the driver and sends no DALI command, so dimming and scenes need push-buttons wired to DALI input devices. Plan those positions with the lighting design, not after the walls are finished.