400w HPS in closet safe?

as long as it isnt touching anything it will be fine. and if you dont do something drastic with ventilation it will 100+ degrees in there. use a aircooled reflector and your temps will be fine and you could put close on top of it without worrying about fires although i still wouldnt.

thats what my set up is. dont have any clothes or anything like that in it. purely used for a grow room. got a bit of a problem with heat stress with the plant but going good so far.

like i said gotta go air cooled

i have a 400w air cooled hps in a closet. it's not dangerous but without fresh cool air the temps easily get in the mid-upper 90s. keep the ballast outside the closet if you can and remember there's only so cool you can keep things by recirculating the same air.

Definitely take everything out of the closet that doesn't absolutely need to be in there. The major thing likely to lead to a fire is if your household wiring is faulty or outdated, or the ballast you're using is old\faulty, or you have flammable materials close to the bulb (use common sense).

I'm using fluorescent's right now, I have a good sized fan giving a lot of good air flow, I also have the swamp cooler on in my house keeping it at 75 degrees or lower.

you can use a couple cfls without an in/out fan, just a small clip on 6in fan blowing at them will do with cfls but as for hps you will need in/out air flow as they get realy hot

Just hang your light from something secure.

And know that HID lighting will give you some serious temp issues in the summer.