The N4000 switches are advertised as top-of-the-rack switches, however they are not. I have yet to find anyone at dell who has authority to allow me to fix our switch without voiding the warranty.
The Problem:
Air Flow. When switches are placed in the top of the rack, they are placed on the hot isle or rack side. We have 2 switches at the top of the rack and they are ingesting all the hot air from the machines below them, additionally, the switches are mounted via rack rails and thus keep the front of the rack open (I am unable to find a panel that can go over the rail mounts) all of which throws the hot air to the front of the rack again to be sucked up by the servers on top once again. These switches create a hot loop.
I would have no problem opening the switch up and flipping the fan direction inside, but I am unwilling to lose the warranty on it. Until Dell can fix this problem or they make other products the reverse the air-flow direction like cisco and even... Force. 10. I would not recommend people buy these switches for top-of-the-rack use.