400W MH - how high to place over plant?

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biostudent

Well-Known Member
I got a 400 watt metal halide lamp, reflector, and ballast. Got an electrician friend to wire it all up but he said that these are fixed 30 feet high or else they will burn through objects or something. I was of the opinion that these would be placed at max 5 feet above a plant. He said it'll burn the plant too.

What should I do? How high do I place it above the plant?
 
OGkushNC

OGkushNC

Well-Known Member
post some pics so we can see what your dealing with, if its 400w I can't imagine having to put it some 30ft away from my plants, 5ft is still too far away but unless there's a pic I have no clue what your dealing with. And not mention im growing with a 400w hps and a 100w mh and i have them both 1ft away from the tops of my ladies.
 
dusty82

dusty82

Active Member
biostudent said:
I got a 400 watt metal halide lamp, reflector, and ballast. Got an electrician friend to wire it all up but he said that these are fixed 30 feet high or else they will burn through objects or something. I was of the opinion that these would be placed at max 5 feet above a plant. He said it'll burn the plant too.

What should I do? How high do I place it above the plant?
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Is your friend an actual licensed electrician? Because if he is then he's pretty stupid and should go back to trade school. What he's should have said is that these fixtures are "typically" mounted at 20'-30' high ceilings in an industrial/commercial application so that at that height they provide an adequate spread of light on the floor. He should have also noticed that when he turned on the fixture he wasn't getting burned, so why would it burn anything else??? My first grow I ran with a 400w High bay MH fixture (Hangs with a reflector pointing down) and had it as close as I could get it. Just hang the fixture until you start to feel the back of your hand get warm when held over top of the plant (not hot, warm), that is a good height to hang your fixture from. Plant will get optimum light and not burn, no need to go 5' away.
 
B

biostudent

Well-Known Member
dusty82 said:
Is your friend an actual licensed electrician? Because if he is then he's pretty stupid and should go back to trade school. What he's should have said is that these fixtures are "typically" mounted at 20'-30' high ceilings in an industrial/commercial application so that at that height they provide an adequate spread of light on the floor. He should have also noticed that when he turned on the fixture he wasn't getting burned, so why would it burn anything else??? My first grow I ran with a 400w High bay MH fixture (Hangs with a reflector pointing down) and had it as close as I could get it. Just hang the fixture until you start to feel the back of your hand get warm when held over top of the plant (not hot, warm), that is a good height to hang your fixture from. Plant will get optimum light and not burn, no need to go 5' away.
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I had sensed some error in his logic as well, but just wanted to make sure. Since I don't know much about electronics, didn't want to take any risk. I read numerous times on this forum of people using 400, 600+ mh at close range so I wasn't exactly sure. My budget is low and can't afford any screw ups. Thanks for the input.
 
OGkushNC

OGkushNC

Well-Known Member
Man I think you can put that bad boy about a 1ft 2ft away easy as long as you have a fan or 2 you should be golden.
 
aCiDjEsUs

aCiDjEsUs

Well-Known Member
That's a regular High-Bay light they come in both flavors MH and or HPS, it's a decent light if you go remote with the ballast so the ballast would sit let say outside of your grow area (they tend to get warm) but over all it's a good light to work with and you said it was free rite? :) You might just want to change the bulb because you don't know how long that bulb was used for and you ready to roll :fire: Here's the link to how to convert to remote ballast if you want to check it out or just ask you "electrician" friend to do it for you :) it really pretty easy. How to Use an Industrial Low Bay Light Fixture?
 
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