by ericmark »
Sun Nov 28, 2010 7:14 pm
I have seen these switches for sale where the edge of the switch lights up but how not sure. If they connect between line and switch line that would mean when switched off there would still be a current flow although only a few milliamp. With electronic discharge lamps this would build up and cause the lamp to flash every so often as the lamp tried to start. So clearly should not be permitted. The only other option would be to use the earth as a return again not really the way to do things.
There are clues in the adverts "# Works with many energy saving light bulbs
# List of compatible Energy Saving light bulbs" and "Not compatible with 240v LED light bulbs" The "Litswitch" does not say how much current can flow when switched off but likely just a couple of milliamp. It is noted the method shown in their PDF for connecting two way switches is not the method used by most electricians. In fact it as shown would cause EMC problems as they show different route for feed and return cables.
Nearly every manufacture publishes how there products comply with a BS or EN BS number and I see no such claims on this site.
Wikipedia says:- Illuminated switch
An illuminated switch in the off position
An illuminated light switch has an internal light source (either a neon lamp or an LED) which allows the user to locate the switch in the dark. Most European illuminated switches are two pole requiring the live and neutral wires to pass into the switch which enables the neon to be powered directly from the mains via a resistor. The internal light source in a single pole illuminated switch derives its power when the switch is OFF from current passing through the external light bulb. Single pole illuminated switches work well with incandescent bulbs, non-electronic fluorescent light fixture and halogen lighting, but they can cause a few compact fluorescent lamps to behave erratically. The current through the neon lamp in the switch can slowly charge the internal input capacitor in these lamps, until they begin to operate and produce a brief discharge. This cycle may repeat indefinitely in some cases, resulting in brief repetitive flashing while the switch is in the "off" position.
The point is that although the current is low when connected to a switch mode device it can build up to a dangerous level and I would only fit one in exceptional circumstances.
