Light fitting works with 2.2 watt bulbs, not with 3.8 watt bulbs

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David_Dublin

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Hi. Wondering if we have any electrician types on here?!

I've a light fitting which takes 4 bulbs, E27. It's on a dimmer switch. When I fit 2.2 watt bulbs they light fine, no issue. They aren't dimmable bulbs so I bought dimmable ones. But these won't light, and I can't work out why. All are LED bulbs.

The dimmer switch seems to be an ample spec - 10 lamps and LED max 120W. Could there be something in the light fitting itself? When I screw in a single 3.8 watt bulb it lights, albeit very dimly. When I screw in a second one, that one lights (v dimly too) and the other stops lighting.

So it feels to me like either the dimmer is the issue or there is something in the fitting that prevents enough power getting into the bulbs. I had a look at the fitting and I can't see anything that might be doing this though.
 
Done a bit more digging.

The power rating for the dimmer that won't fire the 3.8w bulbs is 120w.

When I rewire the switch to run the light through a 1000w switch, the bulbs fire bright. So it must be the dimmer. Strange though that the dimmer rated as 120w wont even fire 1 3.7w bulb.
 
David_Dublin said:
Strange though that the dimmer rated as 120w wont even fire 1 3.7w bulb.
Click to expand...
Not all dimmers are capable of dimming LED bulbs, and dimmers generally have a minimum load, even many of the LED specified dimmers need 5W . Check the specs of the one you have, do you know make / model?
 
Thanks @Leo

The dimmer is a V-Pro, the label on it says Up to 10 lamps, LED Max 120W. 1 or 2 way dimmer switch

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Check the code on the products here, but the spec of the one linked states dimmable 0-120W, which suggests they should work. There are support contacts linked on that page.
 
I think I know the issue. Seems like the dimmer is not powerful enough . 110w dimmer means it can power up to a total of 11watts of bulbs (not 110 watts, curiously you have to divide the dimmer power by 10), from what I have read.

If I want to power 4 x 3.8 watts bulbs, I'll need a dimmer with power = 3.8 x 4 x 10 = 152 watts.
 
Turns out by re programming the dimmer I was able to get this working.....trial and error, not a science.
 
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