A new fan, particularly if it's a quality type with ball bearings, ain't gonna cause any fires... unless it gets a cat stuck in it or something... and even then, it ought to have a ~80-120C thermal fuse in the motor winding, preventing tabby flambé.

If you STILL can't sleep, run the friggin' fan on a power strip with a fuseholder fitted with a flea-current fuse. It'll probably pop at the next power surge... but ya know.
Al B. Fuct Reviewed by Al B. Fuct on . a question about extraction fan.... im working from out a small cupboard with one NL Fem. She is doing well...12/12 into the second week. Should I keep the extraction fan on 24hr? its summer where I live. I have the lights on at night to keep temp down and off during day.....usually around 25deg during daytime. another thing, the extraction fan im using is brand new, but im worried if I have it on 24hr or too much it could overheat and cause a fire.....is this possible or am I paranoid? or would it eventually just burn out? Rating: 5