Zen83237 wrote:


"Mike Clarke" wrote in message
et...
Zen83237 wrote:

I see, the Government in their wisdom are phasing out filament bulbs,
maybe they need to tell industry making the fittings and switches then.

Well the instructions with the last few PIR lights I bought specifically
said that CFL's were not suitable for use with them.

--
Mike Clarke

With respect this is not a PIR, a room switch with inbuild light sensor to
switch the lights on a dusk for predetermined interval.

Fair point, which I'd overlooked.

One reason why PIR's and CFL's don't mix well is that PIR's invariably
switch the lights on for brief periods which is a mode of use that CFL's
are not suited to. Clearly this doesn't apply to dusk to dawn switches.

The other reason why CFL's are a problem with some PIR's is that the sensor
requires a small current to flow through it from line to neutral, the
resistance of a filament bulb is low enough to provide this but a CFL
doesn't provide the right conditions for this with the result that the bulb
may flicker on and off. Domestic dusk to dawn switches sold as replacements
for conventional switches depend on this too and so will not be suited to
use with CFL's. The manufacturers will certainly certainly be aware of it
and ought to point this out.

--
Mike Clarke