Dimmers & Controls for LED Lights

There are thousands of different dimmable LED light fixtures on the market, but only three major types of dimming method: mains dimming, Dali or DMX. Let’s explain them:

Mains dimming

Mains dimming is the oldest dimming protocol and is the type most likely to be seen in the home, as well as in shops, bars and restaurants.

Dali

DALI (Digital Addressable Lighting Interface) is generally used to provide area lighting control over a number of lighting circuits. It relies on an additional two-core cable connection between the dimmer control and the LED driver.

DMX

DMX (Digital Multiplex) was developed originally for the entertainment world, where it’s used to provide dynamic lighting effects across very many lighting channels. In the architectural world, DMX works best for colour-changing and effects illumination, so there is a very close tie-in to LED performance.

So choose what kind of dimming you want before you select any LED luminaires.

Most lighting control systems offer a variety of dimming protocols, the languages which they use to communicate with the lamp or driver. When you’ve chosen the method that’s right for your installation, you need to get LED drivers which match the performance and the protocol. 

There’s a simple commercial equation that should be borne in mind: cheap = risky. Avoid cheap specifications, particularly of products like LED tape and always check with the control manufacturer that your preferred LED product is compatible with their system.

It’s very important to check that the proposed dimmer works with the selected LED lamp before committing to a specification. Test before you buy.

Some domestic dimmers cannot ‘read’ the low loading of a LED lamp, so requiring an additional electrical load to be connected in order that the light will be recognized by the dimmer, contrary to any desire to reduce energy consumption, of course.

The simple answer is to use only those dimmers that have been designed for LED loads.

All retrofit lamps are intended to replace an existing filament lamp, tungsten or tungsten halogen. That means that there are alternatives across the range, from the ordinary GLS lamp (the light bulb), to directional lamps for spotlighting and even chandelier-style candle lamps, some of which work to great, sparkling, effect. The inherent problem in every retrofit lamp is the limitation on physical size.

A retrofit lamp is no good if it doesn’t fit in the intended light fixture. And however perverse this may sound, that essential feature of a retrofit lamp hasn’t stopped some LED lamp manufacturers from producing lamps that simply don’t fit. It might make for a better engineered product, but it may not fit into the required fixture – so it’s good to check.

It’s never a good idea to mix LEDs from different manufacturers on the same dimming circuit. On the basis that every LED will have its own design of electronic circuitry, the dimmer probably won’t be capable of providing a common signal to each light source. This is a recipe for flicker and hum.