Decoding Dimming Protocols: TRIAC, ELV, 0-10V, and DALI Explained

Dimming protocols are often treated as an interchangeable checkbox on a spec sheet, but TRIAC, ELV, 0-10V, and DALI each control light through a fundamentally different mechanism — and confusing them is one of the more common ways a lighting specification runs into trouble on-site.

What you’ll find in this article: how TRIAC, ELV, 0-10V, and DALI dimming each work, where each is typically applied, and how to weigh the tradeoffs when discussing a system with an electrician or architect.

For anyone who advises on lighting rather than installs it, dimming protocols can feel like a language spoken fluently by electricians and haltingly by everyone else. That gap closes quickly once the four major protocols are understood not as arbitrary categories, but as four distinct answers to the same question: how does a controller actually tell a light how bright to be?

TRIAC and ELV: phase-cut dimming

TRIAC and ELV both dim by altering the AC power waveform itself, rather than sending a separate instruction alongside it.

TRIAC, or leading-edge dimming, cuts the front portion of each AC wave and remains the standard found in most older residential dimmers
ELV, or trailing-edge dimming, cuts the back portion instead, generally producing smoother results with modern LED drivers and less visible flicker
Both require only the existing two wires, which makes either an economical option for retrofits

0-10V: analog low-voltage control

0-10V dimming introduces a second, dedicated signal — a DC voltage between zero and ten volts — that runs alongside the main power line to tell the driver how bright to run.

Ten volts corresponds to full brightness, zero volts to the lowest available level, with a proportional range in between
The added wiring is a genuine cost, but the payoff is smooth, dependable dimming across a wide range of fixtures
Widely regarded as the default commercial protocol, from open-plan offices to large-format retail

DALI: digital addressable control

DALI, the Digital Addressable Lighting Interface, departs from both approaches by sending digital commands rather than an analog signal.

Each fixture carries its own address, allowing individual lights or defined groups to be controlled from a single system
Communication runs in both directions, so the system can confirm status rather than simply issue instructions
Capable of scene-setting and zoning complexity that neither phase-cut nor 0-10V dimming can approach

What a specifier should weigh

Existing infrastructure: a retrofit with line-voltage dimmers already in place will generally favor TRIAC or ELV
Budget relative to scale: 0-10V remains the practical commercial default, while DALI’s higher per-zone cost is best justified on larger or more intricate installations
Commissioning time: DALI requires trained setup and address configuration, a labor and schedule consideration as real as the hardware cost itself

A dimming protocol functions less like a preference and more like a language the fixture and its controller must share. Matching that language correctly is what allows a room to dim the way its designer actually intended.

Faqs

Can a TRIAC wall dimmer control a 0-10V driver directly? +

No — the two systems are incompatible. A 0-10V driver requires its own dedicated control signal and will not respond correctly to a phase-cut dimmer.

Why might ELV be preferred over TRIAC? +

ELV’s trailing-edge approach tends to pair more smoothly with modern LED drivers, typically producing less flicker than leading-edge TRIAC dimming.

Does a small residential project justify DALI? +

Usually not — DALI’s cost and commissioning requirements are best justified by larger or more complex commercial installations where individual addressing delivers real value.

Why does 0-10V require additional wiring +

Because its control signal runs separately from the power line, unlike TRIAC or ELV, which dim by altering the existing two-wire circuit directly.

Can DALI and 0-10V systems coexist on a single project? +

Yes, though not on the same control line — each protocol needs its own compatible drivers and wiring, so the overall system architecture should be planned before fixtures are specified.