I tried searching myself: Who is mining with two R4's powered by a single APW5 PSU inside the United States?  I currently own a single R4 batch #2 and APW5 PSU.  I am interested in purchasing another R4, however I will need an electrician to install a new outlet for me.  I assume a 220V?  I'm curious what all is required.  I assume a C13 power cord to a specific outlet, but unsure of the outlet type?  I'm not sure where to search further.  Thank you in advance.  Ps. My batch #2 R4 quit hashing on one board after several days, but after flashing to a new firmware image from the bitmain website and rebooting, I have not had any issues since.