The house has some grounded sockets but not that particular one at the moment. I know I should get it fixed some how some dayI don't know if you caught my link,
How important is it for you to eliminate single-coil noise?
. Show a way to install without soldering (soldering frightens some/many players who do not mod). Option for crimp connectors could do it. Possibly a switch option to turn it off and on when desired. See if you can get one of the youtube channel people to demo it, phil Mcknight or 60 cycle...www.strat-talk.com
There are people in rural areas who have created their own grounding points using a copper or steel pole into the ground on their land and then running a heavy duty cable to the mains supply box. These days best done by a qualified electrician. No amount of guitar screening or gadgets can remove all noise if the ground path to Earth is faulty :/