Technology

“Low voltage” means two different things

The phrase gets used for the power that reaches the LED and for the signal that tells it how bright to be. They are unrelated decisions, and confusing them is an easy way to end up with a lighting package that cannot do what the drawings promised.

The distinction

Two separate low voltages

A 24V tape run dimmed over DALI is low voltage twice over — for two entirely different reasons. Getting the vocabulary straight makes every later conversation shorter.

Every LED ultimately runs on low-voltage DC. The real architectural question is where the driver lives: inside each fixture, fed from a 120V circuit, or as a separate remote unit feeding low-voltage fixtures. That choice sets efficiency, reliability, replaceability and which dimming protocols are even available to you.

The control signal is a separate wire and a separate decision. It can be analog (0-10V) or digital (DALI), and the same fixture is often available either way.

LOW-VOLTAGE POWER

12V, 24V, 48V DC to the fixture

A remote driver converts mains to low-voltage DC. Safe to handle, required for wet and landscape locations, and what makes trimless details, tape and magnetic track physically possible. The driver sits somewhere cool and accessible instead of cooking beside the LED.

LOW-VOLTAGE CONTROL

A signal pair carrying dimming

A separate low-voltage pair tells the driver what level to run at. Either an analog 0–10 volt level shared by a whole zone, or a digital bus where every driver has its own address.

Power architecture

Where the driver lives

Neither is better. They fail differently, cost differently, and belong in different parts of the same house.

FactorLine voltage — integrated driverLow voltage — remote driver
Driver locationBuilt into each fixture or bulbSeparate remote unit feeding several fixtures
Upfront costLower — fewer parts, simple retrofitHigher — driver, low-voltage wiring, design time
Install effortWires to existing 120V circuitsDriver sizing, voltage-drop and wire-gauge design
Long runsBetter — no voltage-drop penaltyWorse unless wire is upsized (ten times the current at 12V)
ReliabilityDriver bakes beside the hot LED boardDriver mounted somewhere cool — both last longer
On failureReplace the whole fixtureReplace the driver alone; keep the fixtures
Failure isolationFails one fixture at a timeA shared driver takes its whole group dark
Wet & landscape120V at the fixture12/24V — low shock risk, and usually required
Dimming availablePhase-cut (TRIAC / ELV)Phase-cut, 0-10V or DALI, depending on driver
Form factorStandard fixture and lamp sizesTiny apertures, coves, tape, trimless detail
Heat is what kills drivers — specifically the electrolytic capacitors inside them. Roughly every 10 °C of additional component temperature halves useful life. That single fact is the engineering case for remote drivers, and the reason we care where yours are mounted.
Driver type

Constant voltage or constant current

A second split inside “low voltage”, decided by the fixture rather than by the control system. Only one of these is actually the “12/24V” everyone means.

Constant voltage (CV)

Holds a fixed output voltage — 12V or 24V DC — while the load draws what it needs. Fixtures have onboard current limiting and wire in parallel. This is the true “12/24V” category, and the only one a voltage figure actually describes.

  • LED tape and strip, cove, cabinet and puck modules
  • Sized by total wattage plus headroom
  • Voltage drop is the thing to watch on long runs

Constant current (CC)

Holds a fixed output current — 350, 700 or 1050 mA — while the output voltage floats within a rated window to match the LEDs, often well above 24V (commonly around 25–42V). Fixtures wire in series. Quoting one of these as “low voltage” says nothing useful — it is specified in milliamps.

  • COB downlights, linear and architectural luminaires
  • Matched by current rating and LED forward-voltage range
  • Where D4i smart-driver features usually show up
These are orthogonal choices. Phase-cut, 0-10V and DALI drivers all exist in both constant-voltage and constant-current versions. The CV/CC decision follows the fixture; the protocol decision follows the control system.
Connectivity

We support all of it, wired and wireless

There is no single right way to control a light. The method that fits depends on the house, the fixtures and whether anyone can get a cable to them — not on what we happen to prefer. We specify, install and commission across every option below.

LINE VOLTAGE

Phase-cut — TRIAC & ELV

The dimming most homes already have. We sell and support line-voltage fixtures with phase-cut dimming, and it remains the simplest, smoothest answer wherever integrated drivers are the right call.

ANALOG

0-10V

A control pair carries a DC voltage and the whole zone follows it. Cheap, robust, wire-and-go — and not addressable, so zones are set by the wiring.

How 0-10V works
DIGITAL BUS

DALI / DALI-2

Two wires, and every driver has its own address. Groups and scenes live in software and the bus reports faults back. One of the options we support — not the only one.

How DALI works
WIRELESS

No control cable at all

Lutron Clear Connect, Wi-Fi, Bluetooth mesh, Zigbee, Z-Wave, Matter and Thread. Often the answer in a remodel, where the ceiling is closed and a control pair was never pulled.

Remodels are where wireless earns its keep. In a new build we can put any cable anywhere. In an existing house the honest constraint is what you can reach without opening ceilings — and wireless control, or control built into the driver itself, is frequently what makes addressable dimming possible at all.

0-10V and DALI, side by side

Dimension0-10V (analog)DALI / DALI-2 (digital)
AddressabilityNone — one level per control pairPer fixture; every driver has an address
Capacity per lineOne level; more zones means more wiring64 addresses, 16 groups, 16 scenes
WiringCircuit plus a separate polarity-sensitive pairTwo-wire bus, star or tree; polarity-free
FeedbackOne-way; no statusTwo-way — level, status and fault reporting
Tunable white / colourAwkward; needs extra channelsNative (DT8)
Dimming curveSmooth, but low end varies by driverStandardised logarithmic curve; repeatable
CommissioningWire and goSoftware addressing, a real setup step
Best fitWell-defined zones on a tight budgetGranular scenes, colour, feedback, evolving installs

Low-end smoothness and flicker depend on the specific driver, not the protocol alone. Specify quality drivers either way.

Making it work together

Whatever your control system speaks

Choosing a control method is only half the job. The keypads and hub have to be able to drive it — and in the residential world, the two do not always line up. We work across all of it, and bridge the gaps where they exist.

Within Lutron's residential range, Caséta is a phase-cut system: natively it drives neither 0-10V nor DALI. RadioRA 3 adds 0-10V through a per-zone dimming module, but still not DALI. Native DALI means stepping up to HomeWorks — which is a large jump for what is often a handful of zones.

That constraint is worth knowing before the fixtures are specified, not after.

HOW WE GET AROUND IT

A bridge instead of a tier upgrade

We deploy a DALI-to-MQTT controller that sits between the lighting and the control system, so the keypads you already wanted can drive the protocol the fixtures actually use.

It talks to the Lutron Smart Bridge PRO over LEAP — Lutron’s own local API, certificate-authenticated over TLS on your network. A Pico press is read directly from the bridge and turned into a command on the DALI bus. No cloud, and no smart-home hub in the middle.

  • DALI drivers addressed directly on the bus
  • 0-10V drivers via Shelly 0-10V adapters on the same system
  • Caséta Smart Bridge PRO or RadioRA 3 keypads and Pico remotes, over LEAP
  • Home Assistant optional, for app, voice, sensors and schedules
  • Fixtures, scenes and groups still defined in software

Specify the PRO bridge. Caséta exposes LEAP integration on the Smart Bridge PRO (L-BDGPRO2) — not the standard Smart Bridge. On RadioRA 3 it is the RR-PROC3 processor. Getting this wrong is a cheap mistake to make and an annoying one to discover on site.

Bridged control is excellent for scene recall, set-level and on/off. Native phase-cut or a native 0-10V module still give the smoothest continuous hold-to-dim ramps.

Not sure which way to go?

Tell us the rooms, the ceilings and what you want the light to do. The protocol decision usually answers itself once those three are on the table.