What causes issues with dimming and smart switching of LEDs and how can these problems be overcome? The Design Team at Timeguard shares its advice.
LED is certainly not a new subject these days, as people now want to move on and do more with it. Dimming and smart switching are increasingly the norm, but the adoption of these technologies has uncovered a few more issues for installers that, thankfully, have been quickly solved.
Dimming is no longer a problem, but dimmable LED lamps and their non-dimmable counterparts use entirely different circuitry so, quite simply, you shouldn’t put a non-dimmable lamp on a dimmable circuit and expect it to work! Beware the plethora of older-generation, non-dimmable lamps on the market, and check what a customer is using before expecting a new dimmer to work perfectly.
The most common dimmers are either leading-edge or trailing-edge phase-cut dimmers. Both work by trimming the voltage at various phases of an alternating current’s sine wave to reduce the power reaching the lamp. Leading edge dimmers are traditionally used to dim traditional incandescent and mains halogen light bulbs and have a higher wattage range, up to 1,000W. Trailing edge, or LED-ready, dimmers are for use with LED bulbs which call for much less power.
LED ready dimmers will also allow you to dim traditional lighting, but this can lead to a common mistake in estimating how many LED bulbs a dimmer will support. An LED ready dimmer that will accept, for example, 4 x 100W incandescent bulbs will not support 40 x 10W LED bulbs. Check the rating carefully and, if the packaging isn’t crystal clear about the difference between the LED rating and the “incandescent equivalent”, then we’d recommend choosing a different brand.
A few years ago we started to hear reports of LEDs that were under the control of smart switches flickering, even when they were supposed to be off. In a nutshell, this is because smart switches require a constant current to remain charged, which they draw through the switched live of our two-wire system. This was never a noticeable issue with incandescent lighting but, with low-power LED lighting, that tiny current is enough to trigger flickering.
Installers and manufacturers alike scratched their heads about this for seemingly ages, but every solution involved increasing the size of the smart switches on the walls – just when we’d spent years refining them so that they’re not much bigger than the traditional on/off switches that they’re a direct wire-for-wire replacement for.
Fortunately the team at Timeguard came up with an answer – one that you can buy at the wholesaler for about £20 and that will provide a fix for a whole lighting circuit. The patented ZV900 Automatic Switch Load Controller is simply wired into the circuit in-line and tucked through a standard 50mm ceiling aperture.
So fill your boots and go design the controlled LED system your clients will love!