Dimming Fluorescent Question

[GarryJ]

Hi all.

Just looking for some help with dimming 2 x 6ft fl fittings. Only 2 on circuit and standard wiring. Feed and SL at normal switch just now. I asked wholesalers to source me a solution for the customer as he wanted them to be able to be dimmed. They came back saying change 2 ballasts in fl fittings to Helvar EL1x70sc and change switch to dimmer - Danlers DPID10VDCMB.
They said this will work on existing wiring and no extra cables would be required however looking at it to me there needs to be a 2 core run from switch position to ballast then between fittings which customer does not want. Can anyone assist?
Thanks in advance for any help

 

[davesparks]

You are quite right, you need another cable from the dimmer to the fittings.

Flourescents cannot be dimmed through a normal dimmer, they always require dimable ballasts with a 240V supply and a seperate control signal.

 

[telectrix]

what he said^^^. dimmable ballasts, normal switching on 240V, but with a elv cable from dimmer to ballasts dimmer then applies between 0v an 10V to the dimmable ballast to dim. only other way would be to swap out the fluorescents for dimmable type of light. maybe yo can get dimmable LED tubes.

 

[GarryJ]

Thought that. Clearly shows an additional 2 core control cable on front of ballast they must have got it wrong. Thanks guys

 

[7029 dave]

Why on earth would you want to dim fluorescent lighting?, designed for good light working area's.

 

[Plonker 3]

Why on earth would you want to dim fluorescent lighting?, designed for good light working area's.

Use them a lot in a high street optician where they require good light to do paper work etc then dim light to do eye tests.

 

[Guest77]

It is possible to dim fluorescent lights without special ballasts if they have starters, you can change the starters from conventional to a different type (cannot remember now the exact name for them) and run a length of metal sticky tape along the back of the tube from one end cap to another lol, I wouldn't recommend it with today's technology but it can be done, I have done it and seen it done by others a lot in the eigthies when dimming was a gimmic rather than the norm it is today. With the high frequency ballasts today that method won't work, but if you had an old switch start fluorescent in your garage I bet it would.

 

[telectrix]

Why on earth would you want to dim fluorescent lighting?, designed for good light working area's.

also in medical and vet practices. good bright light to see by, but dimmed down in x-ray room. had same the other week in a vet's. dimmer replacement.

 

[Guest77]

Most decent modern fluorescents come with automatic dimming today, they dim up and down with the lux levels in the room without the occupier of the room even knowing it is going on, used a lot in schools and colleges for student concentration and proper lux level working conditions. Thorlux is a main manufacturer of this type of lighting, it is the modern way Dave.

 

[topquark]

Cheers Mike, that's today's lesson then

 

[Brightspark2]

Why on earth would you want to dim fluorescent lighting?, designed for good light working area's.

See it in meeting rooms too in office blocks, the lights can be dimmed while the projectors on then put back up to work, or sit around, as they mostly seem to do...

 

[varilite]

Also in telly where fluorescents that are not dimmed are too bright for cameras

 

[Marvo]

It is possible to dim fluorescent lights without special ballasts if they have starters, you can change the starters from conventional to a different type (cannot remember now the exact name for them) and run a length of metal sticky tape along the back of the tube from one end cap to another.....

I know the method you're talking about but you have to be sure the fitting is isolated before touching the tube because you get a whack off the foil tape. Not for the faint hearted and I'm pretty sure this method would be outlawed by the H&S brigade nowadays.

 

[Guest77]

oh yeah for sure, just saying it can work

 

[Marvo]

Sorry Mike, it does work to a point at least but I just wanted to rule it out before people think it might be a viable option as sales of foil tape start rocketing in the UK .