Month: May 2014

Timer Switch for LEDS, Timer Light CFLs & How to get it to work

Timer switches are necessary for turning lights on automatically – whether your not home or just want the have them turn on and off automatically.

Can you use a timer switch with LED or low energy light bulbs.

With the replacement of traditional incandescent bulbs with new low energy CFL and LED bulbs We often get asked by  many people with built in timers why they experience flickering or LEDs remaining on.  We will attempt to explain why timer switches can be used with energy saving bulbs and LEDS,  and how you can resolve the issue in this article.  We will explain (briefly) how electrical timers work first and what causes the flickering.

How Electrical timer switches work.

Electrical timer switches require power to operate.  Light switch timers (eg. those that replace a standard light switch) don’t have a direct power connection.  The draw power to keep the timer ticking over is by passing a very small current through the light bulb.

The filament in old style bulbs passes the small current without any problems and the current isn’t high enough to light the bulb.  the timer simply use the resistance of the filament of an incandescent lightbulb as part of the timer circuitry.

Timer switch CFL energy saving Flickering

CFL bulbs do not have a resistance characteristic to offer the timer – (they are inductive).  The typical electronic timer reaction is to switch itself rapidly on and off due to the inductive element charging and discharging.

Timer switch, LEDS, dimly lit

In the case of LEDs, the small current is enough to produce light with LEDs, meaning they are dimly lit and stay on.  That is why the many timer switches therefore typically require a minimum load in order to operate.  this is usually 40w or more.

This also has the additional issue of the fuse in the timer switch blowing each time the light bulb blows requiring you to turn off the mains before replacing the fuse.

So how can you use a timer switch with your energy saving bulbs?Timer energy saving bulbs flicker

So what can you do?  there are a number of options available,
Get a large resistor.
Some timer switch manufacturers offer a larger external resistor which can be fitted between the bulb and the switch allowing them to operate bulbs of 20W.  these will not fit behind the switch and need to be wired into the ceiling.
Use old bulbs or more bulbs.
With CFLs you could try increasing the number of bulbs so if you have 3 bulbs of 15w you can meet the minimum load requirements of the timer switch.


A timer which works with Energy saving bulbs, LED’s or CFL

There is another solution which does work with all types of bulb – The light switch timer which mechanically operates the light switch and so can be used with any LED or CFL type bulb.

The light switch timer simply operates the existing light switch mechanically as you would with your finger.  This has the advantage that it does not matter what type of light bulb or LED you use you will not have any issues. In addition it does not require any wiring as it is a retro fit solution fitting over the existing switch.


CLF LED Timer siwtch light