gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
091018-2139 EST
The information from wesley1's posts does not indicate that power company current is flowing into the salt water. This is indicated by disconnecting the power company neutral from the main panel. The EGC is still connected to the ground electrode at the main panel. Under these conditions there is reported to be no difference in voltage between the water and the EGC. Thus, no significant stray current flowing thru the ground from the area of the ground electrode at the main panel to the boat dock area.
If the power company installs an isolation transformer, two primary posts and no connection from primary to secondary, at the pole instead of the current single post transformer, eliminates the primary neutral to ground electrode at this pole, moves it away about one pole, and connects the new transformer neutral to the existing pole ground electrode, then there should be little primary neutral current from the new, at least one pole away, remote grounding point to the ground electrode at the customers transformer ground electrode. Thus, negligible voltage from the main panel ground electrode to the EGC at the dock and to the water from the power company. There does not appear to be stray power company ground currents going to the water presently.
You can approximate the direction and magnitude of ground currents with two probes slightly into the ground 12 ft apart by measuring the voltage difference. Two screwdrivers will work as probes.
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The information from wesley1's posts does not indicate that power company current is flowing into the salt water. This is indicated by disconnecting the power company neutral from the main panel. The EGC is still connected to the ground electrode at the main panel. Under these conditions there is reported to be no difference in voltage between the water and the EGC. Thus, no significant stray current flowing thru the ground from the area of the ground electrode at the main panel to the boat dock area.
If the power company installs an isolation transformer, two primary posts and no connection from primary to secondary, at the pole instead of the current single post transformer, eliminates the primary neutral to ground electrode at this pole, moves it away about one pole, and connects the new transformer neutral to the existing pole ground electrode, then there should be little primary neutral current from the new, at least one pole away, remote grounding point to the ground electrode at the customers transformer ground electrode. Thus, negligible voltage from the main panel ground electrode to the EGC at the dock and to the water from the power company. There does not appear to be stray power company ground currents going to the water presently.
You can approximate the direction and magnitude of ground currents with two probes slightly into the ground 12 ft apart by measuring the voltage difference. Two screwdrivers will work as probes.
.