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Well what a coincidence, I was going to post a warning regarding that very problem. I took one look at the bolts, then the power supply and decided to use standoffs then move the power supply away from the sheet of Acrylic so the air vents weren't compromised, but my standoffs were the wrong thread.

What I ended up doing was put one M5 nut on the M4 bolt between the acrylic and power supply. A little fiddy, but when I finally managed to get them all in the supply was clear enough to allow plenty of air into those vents, plus there was no hope of the bolts causing a short.

Actually 3 of the 4 bolts could come in contact with the PCB, a very dangerous situation. You're lucky one of them didn't make the supply casing live. Another "could be" problem I saw was the excess of wire used in the build. Long lengths of small diameter wire can show too much resistance, especially with the Hot Bed heater and Hot End drawing a lot of current. I spent an afternoon shortening every wire on the printer. The end result is a lot neater too. Combine those two problems and it's no wonder other guys were getting blown power supplies and that of course could lead to blown controller boards.

I suggest anyone with a Prusa I3 checks their setup to ensure they don't have an accident waiting to happen. Spread the word to any newbies about to start building too. Thanks Francisco, a good find.