Grounding Shielding

My guess is that you've connected to earth carrying a magnetic field from the area-wide electric system.  I have a body voltage meter and one of those grounding (Earthing) pads.  I grounded to earth where the magnetic field was .05 mg, which supposedly is low for civilization, and it greatly increased body voltage when feet were on the pad.  Then I connected to the neutral plug on the electric outlet and could get the body voltage meter (BMV) to zeros using the pad.  That is until everything changed when I became more EMF affected.  Rechecked BMV and sure enough when I put my feet on the grounding pad the BMV skyrocketed.  I think it's another potentially harmful gimmick to waste your hard earned $$ on.

Does your water enter the house on metal pipes?  It comes in, goes through a water meter, and then does it exit onto PVC or metal pipes?  Magnetic fields are created whenever current flows through wiring, by running motors, wiring errors which estimates say over 90% of homes have - my house had many and the magnetic field went to 6 mG every time a light was turned on, power lines, and from the electric utility using earth for a neutral instead of beefing up their own neutral wires to return the electric signal back to the substation - almost all do it regardless if there are laws against it.  There are probably other things which create magnetic fields, but these are what come to mind.

We had a high magnetic field on our copper water pipes which BruceM on this list instructed us how to fix by splicing in pieces of PVC wherever water pipes entered and exited the house.  We disconnected the ground to the water pipes also.  You might consider asking Bruce about this.  He may no longer be on the list, which would be a great loss since he's an electrical engineer who is also ES.  If you can't contact him here, email me off list and I'll try and connect you.

An after thought, have you ever gone through your house room by room when nothing was turned on, done a magnetic field read and then switched on a light to see if the magnetic field rises?  http://emwatch.com/house-wiring-radiation/

Poor House Wiring Causes Strong Magnetic Fields | EM Watch emwatch.com In houses where magnetic field radiation is higher than usual, poor house wiring is often the cause. What kind of wiring issues give rise to a high EMF?

Sailplane wrote:

If you live in civilization, the earth is carrying a magnetic field from our outdated Wye electrical distribution system.  Because of it's poor design, earth around your home is going to be carrying this field with some homes being in a better spot than others.

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.  The field entered pipes in my basement and two stories up I would get a head jolt when turning on bath water.  Even though it was a low magnetic field, I got very affected when sitting on a first floor chair which was over the pipes.  Gas pipes touching earth and entering a home can also carry high magnetic fields and should be fixed by the utility with a dielectric.  I found 25 mG on gas lines coming into a local church.  RF shielding will not block magnetic fields.  I used a gator clip plugged into the ground of an electrical outlet for my RF wall shielding foil at another house, otherwise it was a shocking experience when touching it.  I highly suggest you talk with BruceM since he's an expert on grounding issues.  Most electricians are clueless about magnetic fields being a problem, but as we ES know, they cause a world of hurt.