First grow, looking for advice on venting and wiring

im planing my frst grow and am going to do it in my garage attic. I have sectioned it off with black and white plastic and put down floorboards over the rafters. im using a 400w envirolite with thick fireproof insulation overhead in case of infra red sensors on copper-choppers. the floor area is painted white along with the gable wall and the floor area is about 8x8 feet with the ceiling around 5 feet at the ridge. i wanted to know

- What kind of fans to use, ie. do i need an intake and extractor fan or is there a home-made method

- My main worry is that i am currently running an extension lead from a socket in the corner of the garage up into the attic which will obviously raise a few questions to ppl whoo see it. On the garage ceiling there are 2 flourescents and the wiring is in the attic space. does anybody know how i could hook up the envirolite directly to these cables without killing myself??

- What kind of inexpensive grow mediums can i start my seedlings in?

Thanks for reading, any advice greatly appreciated:thumbsup:

you want an inline fan hooked up to a cooltube and a carbon filter

if you dont know electricity dont mess with it, it will kick your ass, or burn your house down
if you feel comfortable, flip the breaker off and wire a wall plug using the lights power source (splice the lines in) then plug the lights in normal to the wall plug

a plain soil pearlite mix

thanks for the advice man. so by plain soil/perlite mix do u mean multipurpose compost/perlite or just plain topsoil/perlite? im a complete noob at this so sorry if these questions sound stupid.

Also about the wring of the light; im assumiing the power to my house is running on a/c because there is one mains cable coming into the garage directly connected to a double socket.Attached to the double socket are 2 cables leading into the attic. im assuming that one of these is connecting the ceiling flrs to each other and the other is returning the current to the mains. so if i turned off the mains, spliced the wire in between the 2 ceiling flrs and connected a socket, would i be in business?

And with the venting, im gonna hook up an inline fan and flexihose leading to the soffit vent to extract the air. as far as air intake goes, would u suggest buying another fan for this (funds are running low at the mo) or is there cheaper method ie. CO2 tablets etc.
thanks again 4 the advice and looking forward to any input:thumbsup::smokin: