Dimming Protocols Explained: DALI, Triac, 0-10V, Casambi and Push Dim

Short answer: choose DALI when you need individual or grouped control, scenes and integration with a building management system; Casambi when you want that level of control without running any control cable; phase (Triac) dimming for simple retrofit on existing wall dimmers; 0-10V / 1-10V only where a commercial system already uses it. The protocol is fixed by the driver inside the light fitting, so it has to be decided before you order — not after the lights arrive.

This guide explains how each protocol works, where each one fits, and the mistakes we see most often on commercial, gallery and residential projects. Our dimmable products are tagged with their dimming protocol, so you can filter collections by it.

The protocols at a glance

Phase dimming (Triac, leading edge and trailing edge)

Phase dimming is what most people mean by "dimmable". The wall dimmer cuts part of each mains half-cycle, and the LED driver in the fitting reads that as a lower light level. No extra wiring is needed, which is why it suits retrofit.

• Leading edge dimmers were designed for incandescent and wire-wound transformer loads. Trailing edge dimmers suit electronic LED drivers far better and are what we recommend for LED.
• Every LED fitting on a phase dimmer must be marked as phase or Triac dimmable. A non-dimmable driver on a dimmer will flicker, buzz or fail early.
• Check the dimmer's minimum load as well as its maximum. A few low-wattage LED fittings can sit below the minimum and flicker at the bottom of the range.
• All fittings on one dimmer move together. If you need separate zones you need separate dimmers.

On Toplightco, products listed as Triac Dimmable (SLV's "PHASE" fittings, for example) are phase-dimmable.

0-10V and 1-10V

These are analogue systems: a separate pair of control wires carries a DC voltage, and the driver sets its output from it. They are robust and simple but have real limits:

• Control is per circuit or group — you cannot address one fitting on its own.
• The signal only dims; switching off still needs a relay or switch on the mains supply.
• There is no feedback, so a failed fitting cannot report itself.

We would only specify 0-10V or 1-10V to match an existing control system. For new work, DALI does everything they do and more over the same two wires.

DALI and DALI-2

DALI (Digital Addressable Lighting Interface, IEC 62386) is the standard for commercial lighting control. Each fitting has its own address on a two-wire bus, so a single cable run can control fittings individually, in groups, or by recalled scene.

• Up to 64 drivers (control gear) per DALI line, arranged in up to 16 groups with up to 16 stored scenes. Larger schemes use multiple lines.
• The bus is two-way: fittings can report lamp or driver failure, which matters for maintenance and emergency lighting.
• A DALI bus needs a bus power supply, normally built into the controller or gateway.
• DALI-2 is the current certified version of the standard, with tested interoperability between brands of drivers, sensors and controllers. Prefer DALI-2 on new projects.
• DT6 and DT8: standard single-colour LED drivers are Device Type 6. Tunable-white fittings (adjustable colour temperature) use DT8, and need a controller that supports colour-temperature commands.

Many DALI drivers — including LEDSC4's DALI-2/Push fittings — also accept a simple push switch on the same terminals, so one fitting can be used on a full DALI system or with local push dimming.

DALI on track

Standard 3-circuit track carries mains only. To run DALI to tracklights you need DALI track, which adds two data conductors (D+ and D−) to the profile, and tracklights fitted with the matching DALI adaptor. DALI track systems are not interchangeable between brands in the way standard 3-circuit track largely is, so keep the track, feeds and DALI adaptors within one system. Our 3-circuit track guide explains how to identify DALI track on site. If you have standard track already installed, Casambi (below) is usually the simpler route to individual control.

Push dim

Push dim (also called switch-dim or touch-dim) uses an ordinary retractive push switch wired to the driver's control terminals: a short press switches on or off, a long press dims up or down. It is cheap and reliable for a single room or zone, and needs no dimmer module. Keep the number of drivers per switch within the driver maker's limit, and avoid illuminated push switches, which can confuse the driver.

Casambi

Casambi is a Bluetooth Low Energy mesh: each Casambi-enabled fitting talks to its neighbours, and the whole network is set up and controlled from a phone or tablet app, wireless wall switches or sensors. No control cable is needed — the fittings only need permanent mains power.

• Individual control, groups, scenes, timers and daylight-linked schedules, all configured in the app.
• Ideal for retrofit, listed buildings and anywhere new control cabling is impractical.
• On standard 3-circuit track, Casambi tracklights give per-fitting control with no DALI track — the circuits simply stay live and the light level is set wirelessly.
• Casambi can also bridge to DALI through gateway devices on larger projects.

The trade-off: the system depends on correct commissioning and on someone owning the network credentials after handover. Make sure the client receives them.

Zigbee

Zigbee is a wireless mesh used by many smart-home systems. It is a sensible choice when the client already runs a Zigbee hub; for commercial projects, DALI or Casambi are better supported by professional lighting products.

Which protocol for which project

Five mistakes to avoid

1. Ordering "dimmable" without saying which protocol. A DALI driver will not dim on a wall dimmer, and a phase-dimmable driver will not respond to DALI.
2. Mixing protocols on one circuit and expecting them to behave together.
3. Putting DALI tracklights on standard track. Without D+ and D− in the track the fitting cannot receive commands.
4. Forgetting DT8 for tunable white. A DT6-only controller cannot change colour temperature.
5. Not handing over Casambi or DALI programming at the end of the job, leaving the client unable to change scenes.

Frequently asked questions

Can I dim a DALI fitting with a normal wall dimmer?

No. A DALI driver ignores a phase-cut signal. Use a DALI controller, a DALI push-button interface, or — if the driver supports it — push dim.

Is DALI-2 compatible with older DALI fittings?

Generally yes: DALI-2 controllers can address original DALI drivers. The benefit of DALI-2 is certified interoperability, especially for sensors and input devices.

Do I need DALI track for dimmable tracklights?

Only if you want DALI control. Phase-dimmable tracklights dim from the circuit's dimmer, and Casambi tracklights dim wirelessly on standard track.

What does "Non-dim" or "On/Off" mean on a product?

The fitting's driver is not dimmable. It must be on a switched circuit only.

How do I find fittings with a particular protocol?

Open any dimmable collection — for example Dimmable Lights — and use the Dimming filter to choose DALI, Casambi, Push dim, Triac, 0-10V or Zigbee.

Shop by dimming protocol

• 3-Circuit DALI Tracklights
• DALI-Dimmable Pendants
• Casambi Bluetooth Tracklights
• Dimmable Downlights
• LED Drivers & Controls

Not sure which protocol your project needs? Send us the drawings or a description of the space via our Trade & Projects page, or call 0207 183 5252, and we will recommend a control approach and matching fittings.