When I measure current in the grounding strip coming from my house electric panel to the water pipe using clamp meter I am getting slowly fluctuating value from 1.5 A all the way to 4 A. In my understanding (I have PhD in physics and I work as an electronics engineer, so it is a reasonably good understanding) this strip is normally not supposed to carry any significant current.
Now, this current is not a result of any problem inside the house. The ground and neutral wires are bonded together inside the panel (I've checked), so even if something in the house leaks current to the ground wire this current returns to the neutral in the panel, it does not go into the grounding strip.
I am reasonably sure that utility neutral is bonded to earth at street transformer as well, so ground strip and water pipe and earth is just another way for current to return to the transformer, parallel to the neutral utility wire. But utility wire is 1 inch thick metal conductor and creates a very easy path for current to return, there should not be any reason for 4A of current to go through the grounding strip unless there is something wrong with utility neutral.
Is there any other explanation? I started measuring things because my power consumption is abnormal and I am looking for a reason.
Best regards, Alex.