Timer Switches For Lighting

[chrisnewmanuk]

Hi

Im just about to get my tank delivered (wednesday all being well) and I want to get a time switch for the lighting on it.

Ive looked at some from Homebase but they specifically state "not for flourescent, low energy or discharge lighting"

Anyone know somewhere that sells timers that are "ok" on flourescent tubes?

Thanks

Chris

 

[Silverlady]

I bought mine at B&Q i didnt notice anything about special lights onthe package. Mine works O K .

 

[chrisnewmanuk]

I bought mine at B&Q i didnt notice anything about special lights onthe package. Mine works O K .

Thanks, I'll pop up to B&Q and see what they have - there is an electrical wholesaler down the road who actually sell to the public (shock horror!) so I'll see what they have too

 

[andyj]

Argos also sell them

I bought a pack of 3 for about £10 if I remember rightly

Andy

 

[emo]

Argos also sell them

I bought a pack of 3 for about £10 if I remember rightly

Andy

That's right, I use the Argos ones, and have for a year now for my lighting. They work absolutely fine.

 

[BigC]

Argos multipack x3. for me also. No problems thus far.
Regards
BigC

 

[chrisnewmanuk]

Hi

I found out the reason why they "shouldnt" be used. Some tubes can draw upwards of 30 Amps at startup - which of course is catered for on some *lighting* circuits but not on *socket* circuits (13A). Although most dont draw that much at startup, some do and actually fuse the timer switch contacts whilst either blowing the switch or the tube or the main circuit breaker!

Since these timers seem to be 13-15A rated, as long as the tube does suck over that at startup, all will be well! I found something about the ballast in the tubes as well having to be magnetic otherwise there are harmonics problems where the timer switch and the tube ballast battle for supremecy - one eventually dies.

I guess its easier for the companies to say "no tubes" that to give the real reason!!!

Chris

 

[Rooster]

Hi

I found out the reason why they "shouldnt" be used. Some tubes can draw upwards of 30 Amps at startup - which of course is catered for on some *lighting* circuits but not on *socket* circuits (13A). Although most dont draw that much at startup, some do and actually fuse the timer switch contacts whilst either blowing the switch or the tube or the main circuit breaker!

Since these timers seem to be 13-15A rated, as long as the tube does suck over that at startup, all will be well! I found something about the ballast in the tubes as well having to be magnetic otherwise there are harmonics problems where the timer switch and the tube ballast battle for supremecy - one eventually dies.

I guess its easier for the companies to say "no tubes" that to give the real reason!!!

Chris

Mmmmm, where did you get this info ? I would say the author has little knowledge of electricity !
ALL UK lighting circuits are fused at 5A, so a 30 Amp surge would trip the "fuse"

More likely to be the case is that "standard" flourescent tube circuits use a choke which is basically a coil of wire, in series with a starter that pulses electricity on and off through both the choke and tube... this creates a large "back EMF" or high voltage.
I suspect some timers use a transistor, or triac/diac to actually do the switching part... all these are likly to be damaged by the higher voltages at switch on/off...
The timers I have come across use a relay as the switch, which is a mechanical , errr switch, which IS usable with most low (ish) current circuits - including florry lighting....
Get your timer, use the over-ride button to switch on and if you hear a "tick" its a relay and you are safe !

 

[Lateral Line]

I have used mechanical timeswitches for years without issue. I have seen people talking about this here before and was always a little puzzled as to why a mechanical switch operated by a mechanical timer can behave differently from a mechanical switch operated by a Mk 1 digit.

The back emf caused by the collapse of the magnetic field may certainly fry a triac or thyristor of course. But the OP said they should not be used on "low energy" lamps which have electronic starters? The back emf would not arc a mechanical switch as the pulse comes after the conatcts are closed.

 

[chrisnewmanuk]

Thanks for the (correct) info!

Shall go back to the person I found it from and give them the link to this topic!

 

[littleimp]

I used one of these on my twin 400w halides and unsurprisingly it caught fire!!!

You need a contacter you see, see if you are having problems with blown timers get one of these!!