Energy efficient lightbulbs

[Big G]

This is an ‘out of interest’ question.

I’ve just bought some 11W (60W) lightbulbs from General Electric. There’s a puzzling statement on the box though.

It says: Do not use:

1. For photo cell circuits
2. Timer
3. Dimmer switches

I understand why you can’t use on dimmer switches (I think) but why not on a timer or photo cell circuit?

Any ideas?


G

 

[JohnD]

They are likely to have electronic switches which are rated for a resistive load (e.g. a "filament" lamp). The switching load for these lamps will be higher.

However, I am quite happy running them in table lamps off a plug-in timer that is not electronic, but has a sort of electric clock face, and mechanically operated contacts that are beefy enough for a convection heater.

(BTW I also operate some of these in photocell lamps outside, it will be my hard luck if the lamp stops working after a few years. I suspect the manufactures are trying to cover themselves against the risk of claims for premature failure)

 

[Adam_151]

The photocell and timer may use triacs for switching, and there are a few issues I can see here, the first is they tend to let a small amount of power flow when switched off, this wouldn't have any effect on a filament lamp, bit may cause the CFL to flicker when switched off, I'm unsure what startup surge these things have, its possible that when the CFL starts it could damage the triac, and lastly if the circuit is designed to switch resistive loads, it may lack a snubber circuit which may result in it being unable to switch the CFL off in some circumstances.

If your timeswitch or photocell switches with a mechanical relay, then I can't see any problems with using the CFL on it.