LED bulb compatibility with security light switch

3 Jan 2011
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United Kingdom
I'd like to use three, 2.5W LED bulbs in a light fitting switched by a Timeguard security light switch (ZV210). The Timeguard instructions say that by adding an "adaptor" (FLA01), low energy lamps may be used - but seeing as I purchased the Timeguard well before LED bulbs had entered the domestic arena, I guess the instructions are referring to compact fluorescents? If I added the FLA01 adaptor, could I use my LED bulbs?

Guidance much appreciated.
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I'm 90% sure it would work fine. the only issues I know of are dimmer related and affect both cfl and led. I'm using cfl in security pirs fine.
The FLA01 appears to be a resistor and capacitor "snubber" which will absorb the small trinkle of power that leaks through some timers and PIRs.

Without a snubber this trickle of energy is stored in a low energy lamp until there is enough to flash the lamp for a split second. With LED lamp fittings the trickle is enough to keep the LEDs glowing. A very dim but noticable glow when off

The FLA01 almost certainly will prevent LEDs glowing when the timer / PIR is OFF.

Or you could use a contact suppressor which has similar components


The values to use are

Capacitor 0.047uF micro Farads 250 volts AC
Resistor 100 ohms

Which come pre-packaged as a contact suppressor from RS Components

RS Stock No. 206-7847
Manufacturer Evox-Rifa
Manufacturers Part No. PMR209MB5470M100

There are other sources
I can confirm that the similar Timeguard ZV700 is NOT compatible with LED lamps, even when used with the FLA01 or similar snubber. I have one with 3x Philips Master 8w (40w filament equivalent) LED lamps, a total 24w load.

The snubber did stop the lamps flickering when the ZV700 was in manual on/off mode, but when in either security mode the lamps continued to flicker like crazy.

It's a shame nobody makes such a switch properly capable of handling low energy lamps. It can't be impossible, even when replacing a normal light switch wired in series with the lamp/s. The ZV700 and devices like it are being rendered obsolete by energy efficiency legislation that is increasingly mandating the use of CFL, LED and other low energy alternatives.

UPDATE - The electro-mechanical manual on/off switch on my ZV700 has now failed (stuck permanently on) after less than two years of very light use. Poorly designed and poorly made...
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The problem is that the auto circuitry in the switch has to stay live to preserve the timer settings. Obviously, it needs this even when the lamp is off.

It stays live from the constant live at the COM terminal of the switch, returning to Neutral via a suitable conductor in the lamp. So these switches work perfectly with Tungsten/Argon "incandescent) and Tunsten/Halogen/Quartz lamps (also incandescent, but less inefficient than ordinary T-A).

The circuitry also has a path to Neutral via the ballast in a discharge lamp (eg, CFL, Fluorescent Light Unit/tube). However, except, I would cautiously say, except possibly in the case of an electronically controlled ballast, it will not be safe from the switch's Triac's junction being destroyed by back EMFs across the ballast, mainly when this is operating as a choke. An older switch-start FLU unit with an electronic (not hot bulb) starter MAY BE OK..

I have a room with three compact FLUs (2-D tube) - Dar Lighting "Flush" ceiling fittings. One is an older (outwardly identical) unit. With an FLO1 snubber and an electronic starter (only mildly fast and smooth - not a Fastlux) the ZV700 switch has worked, apparently happily, for over ten years.

I haven't tried it with the brilliant Fastlux starter. I daren't!

LEDs also provide a path to Neutral, but via the diodes. So the lamp will probably glow dimly if connected to a security light switch such as the ZV700, responding to the tiny current drawn continuously by the switch.

This seems an unsurmountable problem, though Timeguard offer an expensive solution to: ask them. The problem is that there is no independent Neutral in a standard lighting cable. If light switch boxes were installed with 3-core + earth cable, Timeguard would have the incentive to re-configure this type of switch so the auto circuitry could be wired to a constant Neutral independent of the supply to the lamp (which itself goes to Neutral., but via the lamp).
I had a problem with G9 lamps and electronic switches, it seems not all LED's are the same, some have large capacitors inside, others very little.

It seems down to luck, not what you want to hear I know, but that's how it works.

It seems the larger physical size of bulb more likely it will work OK. Personally where I can I use smart bulbs, and use built in timers.
I don't know if the FLA01 would stop an LED bulb glowing dimly as the circuity of the ZV600 made its connection to Neutral through its diodes.

The FLA01 is intended for connection to a FLU, where there are accessible terminals for its two tails. It should also stop the emf of the ballast of a CFL damaging the triac in the ZV600, but I am interested to know how and where those who have done this have managed to connect it.

It could certainly be tried with an LED, but the problem there for the ZV600 is not back emf. It's the fact of the switch circuity passing a small current through the diodes of the lamp so as to allow the ZV600 to connect to Neutral in the junction box supplying the lamp circuit.

I suggest phoning Timeguard, who should be able to confirm if the problem can or cannot be solved simply and cheaply and, if it can't, explain the device which they sell which is claimed to overcome this problem, and how and where to install it.
I have looked at the data sheet and adverts for the ZV210N don't know if this is the same switch, but it says it has a 9 volt battery inside?

It states min 40w max 300w and to get 40 watt LED is going to be a lot of light, and it does have some features like dusk to dawn and adjustable light level control for dusk switching to compensate for differing light levels within a building. And at £33.54 it is not a cheap device.

It seems not suitable for 3 x 2.5 watt LED bulbs, you don't say what type, I looked at these GU10 bulbs slightly larger at 4.5 watt, and at £8.48 each not much under the price for the switch, they can be set up with dusk to dawn with an off period in centre, if you have internet available, but clearly not a direct replacement.

There was that little in the price of RGB and white only may as well have RGB but we have no idea where your bulbs are, showing a red light may not be appropriate?

However my point is we need to reconsider how we do things today, I have replaced my outdoor quartz halogen flood lamps for carriage lamps with smart bulbs instead of PIR's to give a better spread of light and be able to switch on before I leave the car.

And with just 2.5 watt is it worth switching off? in days gone by the indicator light was that big, is it really worth switching on and off?

The problem is our property was designed in the days of tungsten, and so we are trying to adapt to LED, and this does not always work, I have electronic switches which work with LED, but need around 10 watt load to work well, so now only 2 or the original 5 still in use, I liked them as they worked with a remote control, no need for the phone, but today we seem to be moving to voice commands.

Not sure I like voice commands, last night looked out to realise outside lights on, seems earlier in the evening wife asked for one light on, and Nest switched on more than asked for, but at 18 watt that was not really a big problem.

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