Today we had a commercial job we were working on with another electrical contracting firm where this happened. The fittings they ordered were supposed to be dimmable and when connected to the C-Bus universal 4 channel dimmer, erratic behaviour occurred with that group of lights. In the end it was found that those 20w LED fittings were in fact not dimmable. We also found out that a dimmable version was available but it required extra wiring for DSI or Dali control dimming. It was too late to add this.
1. Phase control dimming – leading and trailing edge.
2 . DSI dimming
3. Dali control dimming
4. analogue or 0-10v dimming.
The purpose of this article isn’t to discuss these 4 types but just make the point that dimming today is not as simple as it used to be especially when it comes to the new electronic LED and CFL type light fittings.
In domestic premises the majority of dimming with phase control dimmers are what as know as leading and trailing edge. When you buy fittings that you want to dim, make sure that the driver or transformer is dimmable and that it works for either leading or trailing edge dimmers.
The problem is more of an issue with many questionable imported LED fittings being retrofitted into existing homes with older dimmers. As a general rule of thumb though, if you stay with quality and leading brands, they have usually done their homework and made sure that compatibility is achieved somehow.
Clipsal have just released some excellent dimmable LED fittings and lamps that can be installed into their own fittings or substituted into other brands of fittings. They have made sure that these LED lamps dim with their new style traditional dimmers and also are compatible with C-Bus dimmers.
Here is a link to their brochure http://updates.clipsal.com/clipsalonline/Files/Brochures/A0000253.pdf