i have burned out 2PSU. one was enermax 87+(stock) and 2nd was CHIEFTEC APS-1000C. All they burned out couse power consumption is little more than 1000 Wats! it is 1150-1200! So minimum 1500 Wats PSU is needed for Antminer S2 =((
I agree that the PSU was a poor choice, but where are you reading 1150-1200? At the wall?
Are you sure you burned out the Enermax? I have a number of S2 units and the worst that happens to me is that the PSU overheats because my hosting environment is less than ideal. Power off for 15 mins, then they're good to go.