Energy saving bulbs & time switches

[stuartinlancashire]

Just bought a couple of 11W energy saving bulbs from B&Q as they where on offer for 98p, as we've never used them before I thought we'd give them a try.

One of them was going to go into a lamp thst is on a time switch to come on at night when the house is empty, however I noticed on the box it says you can't use them in conjunction with a time switch, could anybody explain why this is?

 

[THRIPSTER]

The message is on the box so that you realise that you cannot use these in conjunction with a timer switch.

 

[bernardgreen]

The message is on the box so that you realise that you cannot use these in conjunction with a timer switch.

Some timers have solid state ( not mechanical ) relays which leak a small current when OFF. No problem with filament bulbs as there is far too little current to affect the filament. But some energy saving bulbs store this trickle until there is enough to light the lamp for a short flash. This means the lamp although OFF at the timer is flashing once every few seconds.

Also some lamps and appliances have high in-rush current at switch on and the timers switch contact are not able to switch that high current

 

[JohnD]

I use them on time switches anyway. My indoor ones are mostly the old fashioned types with a wheel that goes round and operates it. The outdoor ones are on photocell. I have one electronic timer, it has a plug on one side and a socket on the other, so it switches a 13A load, so it probably has a relay inside. It doesn't flicker.

I have occasionally had flickering on the photocell ones. It seems to vary with brand of switch and lamp. But it doesn't bother me, for the money it saves.

 

[Steve]

It'll be rate.

 

[Silinman]

I have a PIR sensor at the front of the house, and the porch light blew a while ago and I replaced it with a low-energy type without reading the box (never do). Sure enough within about 2-3 weeks the new bulb was no longer working and when I took it out the base containing the elctronics was blackened and burnt out! Only use old style filament bulbs now.

 

[Andrew6180]

I've been reading the topic on time switches and LED lights and do understand that the lack of a neutral is overcome by using at least a 40 watt bulb. But supposing the time switch was controlling a chandelier with 20 3.8w LED bulbs and therefore using 76 watts. Does any know if this would work.
Many thanks

 

[JohnD]

what do you mean by "lack of a neutral?"

 

[JohnW2]

what do you mean by "lack of a neutral?"

I presume that he's referring to single-pole switching.

Kind Regards, John

 

[Andrew6180]

The timer switches I am familiar with replace the light switch and only the positive feed is available and no neutral.

 

[JohnD]

I don't see how the load of lamps in a chandelier has any effect on the lack of neutral in a switch.

 

[RF Lighting]

The timer uses the switched live in series with the lamp as a 'neutral' to power it's electronics. This doesn't work with cfl or led lamps, and causes the intermittent flashing we've all come to know and loath.

 

[Andrew6180]

No I don't know why either. But the suppliers of these time switches do state that the minimum wattage required to make the timer work is 40 watts and they are referring to a single bulb. Currently we have inserted 20 x 25 watt light bulbs into this chandelier and the timer/switch works perfectly with only a positive feed passing through the switch. This chandelier is used for around 5 hours every day using a lot of electricity and it is very tempting to replace the 25w bulbs with 3.8w LED bulbs. However I don't want to buy all these LED bulbs to find that the timer doesn't work, even though we have exceeded 40 watts. I've tried asking the suppliers of the timer/switch but they don't respond and am hoping that someone in the forum has/had a similar situation and knows the answer.

Many thanks Andrew

 

[RF Lighting]

I can't say for certain but I think if you were to leave a couple of standard type lamps in and replace the rest for led lamps you will probably be ok but I don't think anyone will be able to say for sure short of you trying it and letting us know.

You could replace one lamp at a time as they fail with an led, and see how you go on. I'm sure you'll be able to use some, but possibly not all LEDs.

 

[ban-all-sheds]