All the clamping screws on the Smart Plug inlet are color coded to make it nearly fool proof. Please notice that I said nearly.
NOTE: New versions of the 30A SmartPlug inlet will begin shipping with the new set screw design you will see below. There is no problem with this design but the new design makes installation even easier. These guys are constantly looking to make this product the absolute best it can be and they DO listen to the trade and DIY customers, when it comes to feedback!!