electricallightinguk
I've just bought a Luxomat 2-wire Indoor 180-N-R Motion sensing light switch.
Manual here: https://www.tlc-direct.co.uk/Technical/DataSheets/BEG/BE180R2W_User%20Instructions.pdf
I was fitting the device and when reading the instructions discovered it has a minimum load of 50 Watts. I would ideally want to use this with an LED bulb but that is just 7 Watts. Apart from buying a 60 Watt filament light bulb what options do I have? Is it possible to use this with an LED bulb?
Location: UK
Wiring diagram for Leviton PR180 3-Way Wall Mount Occupancy Sensor.
The motion sensor's circuits are probably being confused by a voltage spike caused by an inductive kick from the fan. The voltage levels in the device are disturbed, reversing some voltage comparison so that the light is activated. The problem can be attacked at either end. Containing the surge at or near the fan, or preventing its entry into the motion detector.
http://en.wikipedia.org/wiki/Snubber
Perhaps the fan has no snubber mechanism in place to mitigate inductive kicks when the motor is switched off. Without schematics for the fan and its control circuitry, it's impossible to give a specific recommendation such as "get such and such type of diode and solder it across such and such points".
A suitable film capacitor connected across the power terminals of the fan maybe able to contain the spike, and would make for a very cheap fix. The capacitance doesn't have to be very large (I'm guessing, on the order of .0nnn microfarads), but the capacitor should have a decent voltage rating, of at least a few hundred volts (i.e. beyond the line voltage) so it can take the spike.
http://en.wikipedia.org/wiki/Film_capacitor
The small capacitance of the surge cap appears to be nearly an open circuit to 60 Hz power line AC (a very high impedance). But a voltage spike looks like high frequency content which passes through the cap. The cap will "take the edge off" the spike, so to speak. It just has to do that well enough so that the motion sensor isn't falsely triggered.
Best Answer
This is not really suitable for LEDs. Not only is the wattage too low, but since the switch has no direct neutral connection, it gets its power by trickling a small current through the light. With an incandescent light, the power would be so low that you wouldn’t notice it lighting at all when off. However, with most LEDs, you would probably notice a dim glow or flashing from the light with turned off.
Assuming you have a separate neutral wire at the switch (I have no idea how common this is in the UK), you’ll need to return this switch and get one with a third wire that connects to neutral. Make sure it’s rated for LED lights.