This seems like a really stupid question, but I haven't been able to puzzle it out on my own. I *thought* I knew how to disconnect my house from the grid, but apparently I don't. I recently received PTO for my 3 PW + Solar Roof installation. I have my whole house backed up (no loads were separated out when the system was designed / installed). What is the proper / correct way to disconnect my house from the grid while leaving the PWs and solar operating (i.e. simulate a grid power failure)?