just to provide an update
28 Dec - brought the CPU to SLS to troubleshoot and got a new chassis. Seems like it's a chassis problem. Brought home that night to use and, again the electric shock problem surfaced.
29 Dec - brought it down to SLS again to test, none of the problems surfaced. So ruling out any PSU/chord issue. Initial conclusion seems to be outlet/socket issue at my house. I just tested the new system/chassis with the different sockets around the house, all had the same issue. I tried plugging into a Belkin protector extension, problem still exists.
the thing is, only my CPU is having this problem. My iphone charger or other electronics are not seeing major issues so far with the different sockets. So really, I need to live with it or ask an electrician to check the entire house
I've taped the exterior metallic parts to prevent accidental electric shocks for now