Technical lighting guide
1–10 V dimming and wiring
An analogue control pair tells a compatible driver how bright to run. It does not dim the mains waveform, supply the LED load, or automatically switch the lights off.
For competent electricians. Generic instructions are not authority to work live. A dimmed or digitally switched-off lamp is not isolated. Identify every supply, secure isolation and prove dead with a suitable two-pole voltage indicator proved before and after use. Control buses can connect equipment on other mains circuits.
How the system works
In a conventional current-sink 1–10 V system, the driver supplies a small control current and a compatible controller sinks it to set the pair's voltage. Around 10 V requests maximum output and around 1 V requests the manufacturer's minimum level, not necessarily 10% brightness or off. Drivers on one pair follow the same command; they are not individually addressed.
1–10 V: 230 V power and the control pair
Two functions, not a universal requirement for two independent 230 V circuits. The lighting driver needs its rated power supply (normally 230 V AC in this UK example), while the control interface has a separate function. An electronic controller may also require a permanent 230 V line and neutral, or a specified DC supply; a passive analogue controller may need no separate operating supply. The exact controller instructions decide this.
Where the controller includes mains switching, bring the protected permanent line to its specified supply/relay input and take its switched-line output to the drivers' L terminals. Connect N to the drivers and, if required, the controller. Wire DIM+ and DIM− separately in parallel to the drivers. A controller can therefore need a permanent mains feed as well as an outgoing switched mains feed to the lamps — neither is the dimming pair. A passive controller with an integral mains switch can carry 230 V switching conductors without needing an electronic operating supply.
Conventional 1–10 V minimum level is not off: a correctly rated switch, relay or contactor normally provides operational off. Check driver inrush, maximum driver count and relay ratings. Manufacturer-supported dim-to-off exceptions must be checked, not assumed. If the switching contact is volt-free, it does not supply 230 V by itself: wire its feed and output exactly as the manufacturer specifies. Do not link separate circuits, phases or neutrals.
Which wiring and cable types can be used?
These are cable options, not an approved cable selection for every installation. The drawings show power and control separately for clarity; an approved combined cable is possible under the conditions below.
- 230 V fixed wiring
- Twin-and-earth PVC or LSZH cable can provide L, N and CPC for suitable indoor fixed routes. Singles in suitable conduit/trunking are another option. Select the actual conductor size by circuit design, protection, installation method, grouping, insulation, voltage drop and fault protection — a lighting circuit is not automatically suitable for 1 or 1.5 mm².
- Separate control cable
- Use a dedicated two-core control cable of the insulation rating, conductor size and construction specified for the controller and drivers. Identify DIM+ and DIM− consistently at every end. Check permitted length, resistance/voltage drop, interface current and screening requirements; there is no universal 1.5 mm² or 300 m rule for analogue dimming. A screened pair is only appropriate where specified, with its screen terminated as instructed.
- Combined power and control
- Where equipment instructions and BS 7671 insulation/segregation rules permit, a suitable five-core mains-rated cable can carry L, N, protective earth and two control conductors. Examples include suitable fixed multicore cable or an appropriate five-core flexible connection at a fitting. Check suitability for the route and use; flexible cable is not automatically a replacement for fixed wiring. Extra permanent/switched feeds or other functions may require more cores or a separate cable.
- Core identification and CPC
- Keep green/yellow exclusively for protective conductors. In a five-core cable, brown can be L, blue N and green/yellow PE, with the other two cores durably identified for DA/DA or DIM+/DIM−, subject to the actual identification requirements. Do not assume black and grey are neutral. Sleeve a bare twin-and-earth CPC green/yellow at terminations; never use it as a signal wire. Twin-and-earth alone does not provide two spare control conductors.
- Outdoor routes and final connections
- Use cable, glands and containment suitable for moisture, UV, mechanical damage and the termination environment. SWA may suit protected external or buried routes where properly designed; armour earthing and CPC adequacy need assessment. Suitable flexible cable may serve the final luminaire connection with correct strain relief and temperature rating. LSZH describes fire/smoke characteristics, not outdoor suitability or guaranteed circuit survival in fire.
- Segregation and testing
- Do not assume DA or DIM terminals are SELV. Where a verified SELV/PELV analogue interface is used, preserve its required separation from mains. Sharing an enclosure, conduit or multicore is conditional on the relevant insulation and segregation rules, not simply on signal voltage. Ordinary Cat5/Cat6, alarm or bell wire must not be substituted merely because it carries a low-voltage signal. Disconnect/protect drivers and controls before insulation-resistance testing as instructed.
See the cable descriptions guide for construction examples and the circuit-design tool for its supported design checks. Neither replaces the product wiring instructions or a site-specific design.
Multiple supplies and emergency fittings
One control group or DALI bus can include equipment fed from more than one mains circuit. Identify and safely isolate every relevant source, including separately powered controllers, bus PSUs and emergency batteries, before working; label multiple supplies and provide the required isolation arrangements. Do not disconnect or bridge control wiring live. Emergency luminaires may require a permanent 230 V charging/monitoring feed as well as a switched maintained-lighting input, depending on the exact product. Do not assume a dimming command or a lighting switch isolates that permanent feed. Follow the emergency gear's wiring and testing instructions.
1–10 V is not automatically 0–10 V
The terms are often used loosely, but sourcing/sinking behaviour, minimum level and dim-to-off capability vary. Do not mix interfaces by name alone, or add an arbitrary external voltage source to driver terminals. Ordinary phase-cut dimmers, push-to-dim inputs and DALI interfaces are different systems; only use a documented compatible interface or converter.
Wiring and commissioning sequence
- 1
Choose a matched controller and driver
Confirm an actual 1–10 V interface, its polarity and whether the driver supplies the control current and the controller sinks it. Match the controller's sink capacity to the sum of all driver interface currents. A 0–10 V sourcing output is not automatically compatible.
- 2
Plan separate power and control functions
Provide the driver's rated mains supply and a dedicated control pair. For conventional 1–10 V gear, minimum level is not off: provide a suitably rated mains switching contact or relay where needed. Check LED-driver inrush and the contact's permitted load, not only steady-state watts.
- 3
Isolate and terminate
After secure safe isolation, connect mains line and neutral to the specified supply terminals and CPC to required earth terminals. Connect controller + to every DIM+ and controller − to every DIM− in parallel. Keep each independently controlled group on its own pair. Do not connect mains to DIM terminals.
- 4
Respect the insulation requirements
Do not assume the control terminals are SELV just because the signal is small. Follow the driver's insulation classification and BS 7671 wiring/segregation requirements. A shared multicore is possible only where the insulation, identification, terminals and equipment instructions permit it.
- 5
Test, then set the operating range
Complete the installation tests with sensitive electronics disconnected/protected as specified. Reconnect, energise safely, and check high level, minimum level, smooth dimming and off switching. Verify control voltage only with appropriately rated equipment and competent live-testing precautions; the signal is not a voltage-to-brightness calibration guarantee.
Common fault checks
All lamps stay bright: check the correct input type, pair continuity, polarity and controller operation; an open pair commonly produces maximum output, but confirm the driver instructions. Lamps reach minimum but will not turn off: check the separate switching function. Uneven dimming: check mixed driver types and their minimum levels. Never short or disconnect the pair live as an improvised diagnostic procedure.
Where it makes sense
Commercial or architectural schemes needing straightforward group-level control, including compatible bulkheads, panels and linear luminaires. An extra control pair normally needs planning at installation or a suitable existing cable route; it is not a direct replacement for a two-wire domestic dimmer.
Paul's products: do not assume every Kosnic DD lamp, Blanca fitting, BELL tube or Aurora lamp accepts this interface. Confirm the exact driver/module code and accessories first. A Blanca enclosure alone does not determine the dimming system.
Verified sources and limitations
- Helvar HES98020 manufacturer data sheet: source/sink configuration and separate switching; model-specific example, not a specification for all controllers.
- Tridonic basicDIM Wireless manufacturer data sheet (archived/discontinued): distinct sourcing/sinking analogue modes and switched mains output; not a current purchasing recommendation.
- DALI Alliance — analogue/digital comparison: polarity distinction from 0/1–10 V.
- Helvar 472 converter data sheet, issue 6: model-specific example of mains input, switched-live output and a separate analogue interface. Not a universal controller wiring schedule.
- HSE GS38: safe electrical test-equipment selection.
BS 7671:2018+A4:2026, Chapter 52 (wiring systems), Chapter 53 (isolation, switching and control) and Part 6 (verification) provide the installation framework. This guide is not the licensed standard or a universal terminal diagram; consult the applicable edition and current instructions for every installed product. No printed page numbers are assumed.