DALI Wiring Diagram: Digital Addressable Lighting Interface
This is a free printable dali wiring diagram: download the diagram as SVG or open it and print to paper or PDF.
A DALI wiring diagram shows how a DALI controller, power supply, and up to 64 individually addressable lighting devices are connected via a two-wire, polarity-insensitive digital control bus that operates independently from the mains power supply.
DALI — Digital Addressable Lighting Interface — is a standardised digital protocol for controlling lighting systems. It is defined by IEC 62386 (Parts 101, 102, 201 onwards), which replaced the earlier IEC 60929 annex E specification. DALI allows individual addressing of luminaires, group-based control, scene setting, status feedback, and fault reporting over a simple two-wire bus.
The DALI bus is a low-voltage digital communication line, not a mains switching bus. It operates at 9.6 to 16 V DC (power supply module providing typically 16 V DALI bus voltage), carrying Manchester-encoded digital signals at 1200 baud. The bus is polarity-insensitive: the two DALI conductors (sometimes labelled DA and DA, or simply Bus+ and Bus−) can be connected either way around without affecting operation — each device's input stage handles both polarities.
A single DALI segment supports up to 64 individually addressed control devices (gear: ballasts, LED drivers) plus up to 64 control input devices (sensors, pushbuttons, switches), as defined in IEC 62386-103. The 64-device limit is determined by the bus current capacity (maximum 250 mA on the bus from the power supply) and the addressing space (7-bit short address, giving addresses 0–63).
The DALI bus wiring is completely separate from the mains power wiring. Each luminaire requires two connections: mains supply (line and neutral to the driver/ballast) and DALI bus connections (two-wire, polarity-insensitive). The mains and DALI conductors may be run in the same cable or conduit — no separation is strictly required by the standard, but local wiring regulations may apply.
DALI devices are commissioned by assigning short addresses (0–63) to each device. A DALI controller or commissioning tool sends a broadcast command and assigns addresses either randomly or sequentially. Devices can be grouped (up to 16 groups) and scenes stored in each device's non-volatile memory.
DALI-2 (the certified IEC 62386-2014 and later device profile) introduced mandatory inter-operability testing and new device types: Part 207 (LED drivers), Part 209 (colour control), Part 210 (emergency lighting). DALI-2 devices must carry the DALI-2 logo from the DALI Alliance.
A critical planning point: the DALI bus is not intended to carry significant current to power luminaires. It carries only the communication signal and a small standby current for each device (typically 0.25 mA per gear). The mains power for each luminaire must be routed separately to each driver or ballast.
How to wire dali wiring diagram
- Plan the DALI segment: count devices and map bus topology Confirm the total number of DALI gear (drivers/ballasts) does not exceed 64 per segment. Determine whether additional segments are needed. Plan cable routes for both mains power to each luminaire and the DALI bus conductors. DALI bus topology can be bus, star, tree, or any combination — no specific topology is required.
- Install mains power wiring to each luminaire driver Run mains supply (Line, Neutral, Earth) to each luminaire driver or ballast independently. DALI does not replace mains wiring — each luminaire requires its own mains power connection. This wiring must comply with all applicable electrical codes.
- Run the DALI bus cable between devices Run a two-core cable (minimum 0.5 mm², recommended 1.5 mm²) between the DALI controller, DALI bus power supply, and all DALI drivers in daisy-chain, spur, or star topology. DALI is polarity-insensitive — simply ensure each conductor is continuous throughout the segment. Maintain separation from power conductors as required by local regulations.
- Connect DALI bus power supply to the bus Connect the DALI bus power supply (typically 16 V DC, 250 mA) to the two DALI bus conductors at a convenient point in the segment — typically at the controller location. Ensure only one DALI bus power supply is connected per segment (unless additional supplies are deliberately paralleled within total current limits).
- Connect DALI controller to the bus Connect the DALI controller bus terminals to the two DALI bus conductors. The controller may be integrated with the bus power supply. Connect the controller to the building's network (Ethernet, RS485, or other) if integration with a BMS or DALI-2 application controller is required.
- Commission: assign short addresses using DALI commissioning tool With all mains and DALI bus power applied, use the DALI controller or a dedicated commissioning tool to discover all devices on the bus. Assign short addresses (0–63) to each device. Create groups and scenes as required by the lighting design. Verify each device responds individually to its assigned address.
- Test: verify dimming, scene recall, and fault reporting Test each luminaire individually through its full dimming range (minimum dimming level to maximum). Recall scenes and confirm group commands operate correctly. Check fault reporting — DALI gear reports lamp failure, driver failure, and power failure status back to the controller.
Specifications
| DALI bus voltage (nominal) | 9.5–22.5 V DC (IEC 62386); power supply typically provides 16 V DC |
|---|---|
| DALI bus current limit | Maximum 250 mA total per segment |
| Maximum addressable gear per segment | 64 individually addressed control gear (7-bit short address: 0–63) |
| DALI communication speed | 1200 baud (bits/second), Manchester encoding |
| Maximum bus cable resistance (round trip) | 44 Ω total (IEC 62386-101) |
| Governing standard | IEC 62386 (Parts 101, 102, 103, 201+); DALI-2 certification by DALI Alliance |
| Dimming range | Logarithmic curve, 0.1% to 100% output (IEC 62386 minimum level: device-dependent) |
| Groups per segment | Maximum 16 groups; each device can be a member of multiple groups |
Safety warnings
- DALI wiring involves mains-voltage circuits (supply to each luminaire driver) which constitute fixed electrical work. All mains wiring must be performed by a licensed electrician in accordance with the applicable standard: NEC/NFPA 70 (USA), BS 7671 (UK), AS/NZS 3000 (Australia/NZ), or IEC 60364 (international). The DALI bus itself is low voltage, but it operates alongside mains-voltage circuits.
- Always isolate and verify all mains circuits dead before working on any luminaire wiring, even when only intending to access the DALI bus connections at a luminaire. Mains and DALI conductors may run in the same cable entry or conduit.
- Do not connect more than one DALI bus power supply to a single segment without careful current management. Exceeding 250 mA total bus current can damage bus power supplies and DALI devices.
- Do not use the DALI bus as a power source for luminaire drivers. The bus provides only communication signal current (approximately 0.25 mA per device standby). Each luminaire requires a separate mains power connection.
- DALI emergency lighting systems (IEC 62386 Part 202) have additional installation and testing requirements under life safety regulations. These must be installed and commissioned by qualified personnel with knowledge of the applicable emergency lighting codes.
Tools needed
- DALI commissioning tool or software (laptop with DALI USB interface)
- Multimeter (DC voltage for bus verification, AC voltage for mains circuits)
- Non-contact voltage tester
- Insulated screwdrivers
- Lockout/tagout kit
- Wire strippers and crimping tool
- Cable labels and marker (for conductor identification at each device)
Common mistakes
- Connecting the DALI bus power supply to the mains distribution circuit and attempting to use the bus conductors to power the luminaire drivers — the bus is a communication circuit only.
- Installing more than 64 DALI gear on a single segment, causing address conflicts and communication errors. Count gear carefully and split into separate segments with individual controllers and bus power supplies if needed.
- Using a general-purpose DC power supply for the DALI bus instead of a DALI-rated bus power supply. Non-DALI power supplies may not meet the voltage regulation and current-limit requirements of IEC 62386.
- Failing to commission (address) devices after installation and assuming all luminaires will respond because they are wired. DALI devices respond only to the broadcast address until individually addressed.
- Mixing DALI-1 (legacy) and DALI-2 devices on the same segment without verifying compatibility. While broadly backwards-compatible, some features and device types defined in DALI-2 may not operate correctly with older DALI-1 controllers.
- Assuming DALI bus topology must be a ring or specific structure — DALI works on any topology (bus, star, tree, or mixed) and requires no termination resistors.
Troubleshooting
- DALI controller cannot discover devices on the bus
- Cause: Bus power supply not connected or faulty, bus conductors open-circuit, or a short circuit on the bus dragging bus voltage below operating threshold Fix: Measure bus voltage with a multimeter — should be approximately 16 V DC at the controller terminals with no devices connected. Progressively connect devices to isolate any short-circuiting unit. Verify bus cable continuity through the segment. Replace any device that pulls bus voltage below 9.5 V when connected.
- Some luminaires do not respond to DALI commands after commissioning
- Cause: Commissioning was not completed for all devices, a device has lost its stored short address (power interruption during address write), or a driver has failed Fix: Re-run discovery on the DALI controller to find unconfigured (broadcast-only) devices. Confirm all 64 addresses are assigned if 64 devices are present. Check that the driver's mains supply is present and that the driver's status via DALI query shows no fault flags.
- Luminaires flicker or behave erratically on DALI commands
- Cause: Bus cable picking up electrical interference from adjacent mains cables, bus conductor joints with high contact resistance, or a failing device causing bus noise Fix: Check the total bus cable resistance. Inspect all connections for tightness and corrosion. Try increasing separation between DALI bus and mains cables (or use screened cable). Disconnect devices one by one to identify any device causing bus noise or excessive current draw.
Frequently asked questions
Does DALI wiring need to be polarity-correct?
No. DALI is polarity-insensitive. The two bus conductors can be connected either way around at every device without affecting communication. This significantly simplifies installation because electricians do not need to maintain a specific polarity through junction boxes and daisy-chain connections. The bus driver circuitry in each DALI device handles both polarities.
How many devices can a single DALI segment support?
A single DALI segment supports up to 64 individually addressed control gear (ballasts/drivers) and up to 64 control input devices (sensors, pushbuttons). The 64-gear limit arises from the 7-bit short addressing space and the bus current limit of 250 mA. Larger installations use multiple DALI segments, each with its own power supply and controller, connected at the building management system level.
Is DALI the same as 0–10 V dimming?
No. DALI and 0–10 V (also called 1–10 V) are completely different control protocols. DALI is a digital, bidirectional, addressable bus that allows individual device addressing, status feedback, and scene storage. 0–10 V is an analogue protocol providing a single broadcast dimming signal to all connected drivers simultaneously with no addressing or feedback capability.
Do DALI luminaires need a separate power supply for the bus?
Yes. Each DALI segment requires a dedicated DALI bus power supply, typically providing 16 V DC at up to 250 mA. Some DALI controllers have the bus power supply integrated. Some DALI drivers can also supply power to the bus, but this must be carefully designed to avoid exceeding the 250 mA bus current limit. Never power the DALI bus from a general DC power supply not rated for DALI.
What is the maximum cable length for a DALI bus?
The IEC 62386 standard does not specify a maximum cable length directly, but limits the total bus cable resistance to 44 Ω (round trip). For 1.5 mm² cable (approximately 12 Ω/km per conductor), this equates to approximately 1.8 km total length per segment — far more than any practical building installation. In practice, cable length is limited by voltage drop on the bus, not by distance alone.