# Forum Home Renovation Electrical  Distance between ceiling fan and downlight to avoid strobing?

## skidave

Hi all, 
Just cutting the holes for a ceiling fan and downlights in a bedroom, and was wondering how far from the fan blade tips should the downlights be to avoid strobing? 
The room is 3500mm square, and the ceiling fan is in the centre. I was planning on installing 4 downlights towards each of the 4 corners of the room, 600mm from the tip of the fan blade. 
Does this sound ok, or should I move them further away? 
Cheers!

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## skot

Sounds a little close....depends on the drop of the ceiling fan. 
The lower the fan is...the further away the lights should be. Simple line of sight type problem. 
Stand at the edge of room...take a line from your eye height to the ends of the fan blades until it hits the ceiling...thats where the down lights should go

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## skidave

But wouldn't it also depend on the angle of the beam of light coming from each light? 
I don't know if line of sight would work - for example, imagine you had a room 20m long. If you had a fan at the centre, and took a line of sight from one end of the room, past the fan blades - the distance the light would need to be from the fan blades in that case would be several metres - which probably wouldn't be correct... would it?

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## skot

OK,
Then you will have to know or workout the light angle spread of the downlight so it only skims the fan blades Could be 120°

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## skidave

Are there any electricians in here who can shed some light on this? (pardon the pun)

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## chuth77

600mm from the fan tip is way to close, and anyway will give you too much concentrated light at the centre of the room... 
If you were to work in 900mm from each corner, up to max 1100mm, then it would be best... This gives a nice highlight on the wall, and gives a fairly even light through the room... 
Becarful to place the downlights away from battens and rafters the required clearance... Your electrician will know the details...

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## elkangorito

> Hi all, 
> Just cutting the holes for a ceiling fan and downlights in a bedroom, and was wondering how far from the fan blade tips should the downlights be to avoid strobing? 
> The room is 3500mm square, and the ceiling fan is in the centre. I was planning on installing 4 downlights towards each of the 4 corners of the room, 600mm from the tip of the fan blade. 
> Does this sound ok, or should I move them further away? 
> Cheers!

  What are the dimensions of the room? A drawing of the ceiling indicating the location of the lights & fan would be of great help. Also, what type of lights are you using? What is their "radiation angle"?

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## skidave

Thanks guys, below is an image of the room. The orange dots are the downlights (240v, 11watt energy savers). 
Should I can the idea altogether and just get a light built into the fan?

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## chuth77

Definetly go 900 to 1100 in from each corner. If you have them too far away from the centre, you'll have a black spot in the centre of the room... All the light will be wasted on the walls! 
Double check where your ceiling battens and rafters are located. This will then determine the dimension that you can install the lights...

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## elkangorito

Since you say the lights are "downlights", I assume that they are recessed into the ceiling. In this case, your fan should have little effect (if any) on the radiated light. On the other hand & if any part of the light protrudes from the ceiling, the fan may cause slight interference.

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## chuth77

> Since you say the lights are "downlights", I assume that they are recessed into the ceiling. In this case, your fan should have little effect (if any) on the radiated light. On the other hand & if any part of the light protrudes from the ceiling, the fan may cause slight interference.

  What a crock... Why would you say downlights will not cause strobing? Dude, go and install a downlight too close to a fan and see whether you would be affected!

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## skidave

Does it matter that they are the energy saving type, and not halogen bulbs? I think someone in the shop may have mentioned tha tthe halogen cast a direct cone of light, but the energy saving ones are more diffused. Does this sound right? And would this negate the strobing?

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## Ausyuppy

skidave,
Im no lighting expert, however when I installed new downlights into my property, I has ceiling fans in every room. I cant remember the distances I kept from the fan, however having multiple lights in the room should reduce the strobing (to a point  you wont notice it). I would give you the measurements however I have sold the house now. 
I had a similar setup in every room at my old house however I only had two downlights per room and did not notice any stobing. I have attached a photo of the office which was the smallest room in the house. You can see one downlight, the other is above the photographer. There was no strobing in this room, and the downlight was only 600mm at the most away from the fan. 
Cheers
Steve

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## Make it work

> Should I can the idea altogether and just get a light built into the fan?

  We just installed a fan & light combo (clipper style) and it still strobes on the top of the wall and ceiling. 
If you go this way, choose an oyster style light and you won't have a problem. 
Also, I put 2 sets of fans & lights similar to what you describe in another room and they are quite ok. 
The lights are recessed low energy, 15W each , 3 per fan, placed in a triangle with each about 1200 from the centre of a 1200 diameter 4 blade fan and I have not been bothered by strobing. 
BTW, lighting shop guy is spot on about low energy, compact fluro style lights being more diffused than halogen.

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