Posted by sailplane on
URL: https://www.es-forum.com/Grounding-Shielding-tp4030801p4030815.html

Fog Top wrote

The magnetic field is traveling from the earth outside your home where your metal pipes touch it and carried in onto the house metal pipes.  The PVC splice, just a small piece, near where the water pipe enters and just before it leaves the house such as outside spigots where the splices need to be placed to stop the mG from traveling on the copper.  

Ok, I just measured the neighborhood on bike. some places are worse, some are better like you say, even on the street. 1-2mG is the norm.  Some places have 4mG.
Turned off main, I have 0.3mG in my house with mains off completely.

Probably nothing more I can do, the pipes don't carry any magnetic field upstairs, it's all just down there, which is quite far from me.  Probably hooking up the ground to the shielding causes it to emit some low level RF,... I don't have anything sensitive enough to measure that, but this is my guess.