you can position your ballast however you want. i keep mine on a shelf in a closet inside my grow room. mine sit on one inch rubber, helps isolate the buzzing and ballast. i typically run five thousand watt ballasts in each room. four hps and one mh. as long as your circulation is decent you won't have to much of a problem with heat. depending on how you are doing your lighting, mines vertical(hanging), make sure they are where you can service them if need be. if you use a longer cord from the ballast to the socket, make sure you take in account for how much amperage you are drawing and make sure to size the cord wire correctly. a safe rule of thumb is never use anything less than twelve gauge wire, for up to about twenty five feet. this is for thousand watts lights. one of the biggest mistakes people make, is using cheap timers. spend forty bucks on ebay and pick up a used intermatic timer, or eighty dollars new. they are easy to use, very dependable, and made to take the amperage of lighting. one timer will typically be safe for about forty amps. they can be used for 110 or 220.