How to fix glow and flicker

The technical team at Timeguard advise on how to eliminate glow and flicker in LED & CFL lamps in standby/off mode.

The evolution of LED, coupled with smart switches and home automation systems, has certainly delivered on energy saving. But like with so many new technologies in the past, LED brings its own collection of problems for the installer.

You’ve only got to take a glance at the internet to see electricians desperately trying to find answers to the same problems with LED lighting. Often the complaint will be that an installer has replaced a customer’s old incandescent lamps with LED lamps only to find that the damn things won’t switch off! “No matter what you do, they just glow or flash”, or “The automatic light switch seems to have stopped working after a week! “

What’s causing the problems?
As hinted above, the ‘culprit’ is the automatic switch, but there is finally a fix for the problem.

LED lamps use a fraction of the power of incandescent or halogen, so quite logically it only takes a fraction of the power for them to illuminate. Any small voltage/current within the circuit can cause LED lamps to glow or flash. Now, most automatic switches are designed to operate as replacements for a standard 2-wire light switches, where there is normally no neutral connection available at the switch. For these to function, a small amount of power has to be drawn down through the switched live connection to operate the switch whilst in standby. This isn’t a problem for incandescent or halogen but can be for LEDs, which continue to glow and flicker.

Another common problem arises when LEDs are switched on: due to the circuitry needed to power the actual LED chips a momentary power surge is created – commonly known as an inrush current – within the lighting circuit they’Re connected to. This can be enough to damage many switches.

What’s the solution?
The obvious answer of changing to a different (and probably more-expensive) LED lamp manufacturer, rarely works. Changing the automatic light switch doesn’t help either (assuming you’ve already made sure the one you put in has a specific LED rating and that it’s high enough). Designers have also tried introducing dummy loads into circuits, but with very limited success.

The one solution that’s having universal success seems to be Timeguard’s patented Automatic Load Controller. It uses semiconductor technology to create the right electrical environment for 2-wire automatic switches and LED lamps to operate in harmony, and there’s no need for manufacturers to modify the electrical design of their automatic switches (timed, PIR or photocell operated) or LED lamps.

The ZV900 works straight out-of-the-box with just about any smart wall switch and lamp combination. It can be used with any make of LED-rated smart wall switch (not just Timeguard’s own models) and off-the-shelf LED or CFL lamps. You simply wire it in series with the lamp and then hide it away by popping it neatly through a standard 50mm aperture.

One device per circuit is sufficient to eliminate flicker and glow in up to 200W of LED or CFL lighting, and it will consume less than 1W itself. In fact, using the Automatic Load Controller can also boost the switching power of most existing automatic wall switches up to 200W, while also providing built-in surge and current inrush protection.