electronic dimmers

[wattsup]

hi guys

Electronic Dimmer switch 2-gang from wickes

Customer supplied the above, couldn't get it to work, thought a dodgy switch, so replaced with the same. But not working again.

I replaced with ordinary 2-gang switch, no problem.

I fixed 4 others electronic dimmers, all 1-gang in other rooms with no problems.
Feeds and switch wires all ok. Lamps are dimmable, gu10 50w halogens (exact same lamps in other rooms), load is only 150w per circuit...anyone had probs with these before
Screwless Flat Plate Electronic Dimmer - Switches & Sockets - Electrical -Tools, Electrical & Plumbing - Wickes

 

[pushrod]

Don't know much about halogen lamps but if they are inductive ( and i think they are if they have the little transformers on them) then you should apply a correction factor of x 1.8 to the wattage of the bulbs which brings it very close to the 300VA limit. A quick check would be to put ordinary incandescent bulb in and see if it will dim ok . If they do you know the dimmers are working ok. I think if you reduce the load on the circuit you might get them to work (bit stupid of a stupid suggestion that as the installation is already there - doh!) or find dimmers with a much higher VA rating. good luck.


Edit ; just thought that as the switch is rated at 300VA maybe it has already been derated??

Also found this on the net-
"The need to de-rate a dimmer
When using Mains Voltage Halogen lamps such as GU9, GU10, GZ10 and Linear halogen lamps, dimmers should be de-rated by 25%.
This helps compensate for the additional load due to arcing at the end of the lamp life cycle. This extra load can damage the dimmer. Where possible it is better to use branded lamps such as those produced by GE, Osram, Philips and Sylvania. Generally these have an in-built thermal link and, should the lamp filament short out, the thermal fuse stops the inrush of current which can damage a dimmer. (LIF Technical Statement No.25). Many cheaper imported lamps do not have this thermal link.
In some cases the number of dimmers on a plate must be de-rated because of the heat generated during normal operation."

 

[SirKit Breaker]

I got called to a problem a while back with a competent DIY'er who had bought one of these Electronic dimmers, but it wouldn't work. When i read the installation instructions the customer had fit and wired it correctly, however it turned out that there was a master and slave unit, he only had the slave and he needed both to make the 2 way lighting work correctly. another umpteen pounds later and all was well.

Sorry just realised you are talking about 1 way and not 2 way lighting.
Cheers...........Howard

 

[Spudnik]

I bet its made by Varilight?

 

[KCElectrical]

The dimmer looks very much Lutron inspired to me, except for the price.Can you get a reading of the secondary side from a meter?That might give you a clue.

 

[wattsup]

Thanks
I get a feed through to the dimmer switch wire connection on the switch, when i connect the actual switch wire the feed dissapears? So it seems some thermal / overload operates. Yet several other switches work in other rooms with 4 lamps in circuit. This one has only 3 lamps, per switch.

I have a conventional rotary dimmer, I'll try that tomorrow...and as pushrod said, i'll try an ordinary incandescent across the electronic dimmer