# Useless



## backstay (Feb 3, 2011)

How many circuits?


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## Ccoop64 (2 mo ago)

backstay said:


> How many circuits?


I planned on splitting the lights between 2 circuits.


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## MikeFL (Apr 16, 2016)

Industry standard on the 0-10V dimming is 0.002A per unit.
You have 15 units.
That's a 30mA total load on the 0-10V circuit.
Use a VD calculator to size the wire so you don't get voltage drop with dimmer lights at the far end.

Power drawn by the lights is not a factor.


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## splatz (May 23, 2015)

Ccoop64 said:


> I couldn't find a product like your normal 0-10v dimmer switches because the lights will pull so much power.


That's not how that works.


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## Almost Retired (Sep 14, 2021)

Ccoop64 said:


> Hello, I'm going to be installing 15, 150W UFO high bay fixtures in a large barn. They have 0-10V dimming and I'm wondering what kind of options I have. I couldn't find a product like your normal 0-10v dimmer switches because the lights will pull so much power. Any suggestion are appreciated and if there is a better way to control everything please let me know. I've only had experience with residential work so these are a little new to me.


amazon is selling such a lite with 21,000 lumens, for comparison a normal street lite/dusk to dawn nite lite is 8,000 lumens
unless that barn ceiling is really high, over 2 stories; it is unlikely that you need that many lumens per fixture
you need to investigate the coverage of each fixture at a particular height, (this will be in the spec sheet of each lite)
usually the recommendation is more fixtures of less lumens

you have to realize that what your eye sees is the light reflected off of objects, and actually not the object itself
in other words a wide open floor space will seem darker compared to a wall with plenty of light reflecting off of it
however, if the barn is full of things like tractors, cows or whatever, those things will be reflecting the light and it will appear brighter

the actual dimmer is inside each lite. the lite will have wires for the power and (usually) a purple and grey small wires for the dimming controls
as mentioned above they are separate circuits. in addition to the power wires, you will need to run dimming wires to each fixture.

Southwire already sells 12-2G romex with the additional purple and grey wires included in the outer jacket
look it up

look the lite up on google and get the specs for it as well as find out how it works
then look up the appropriate dimmer control and get the specs for it as well as find out how it works
most lites come with a short list of some of the compatible dimmers

the web is here for research
but you have to get in the habit of using it 
and not asking questions from ppl who are not involved in the project and therefor dont know all the particulars


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