when you said .... I've seen people running HPS out of standard household sockets. these sockets are connected to a ballast, these are remote ballast which just means the ballast is seperated from the bulb by wire. this means the warm ballast can be placed outside the growroom while the bulb can be placed inside

helps with temperature control. but im pretty sure that all HID(high intensity discharge) lights use a ballast no matter the wattage.