Yep.. and you are correct about mainly being able to see if there is leakage into the water with shore power - because the shore power is definately referenced to the water.
FYI, I when I quickly looked at the OP numbers (below)
Black (power lead) 9.50 Amps
White (common) 9.15 Amps
Green (ground) 0.45 Amps
I had assumed that the current on the white and green (9.15 plus .45) exactly matched the current on the black (9.50)
But.. they dont exactly. The white and green add up to 9.6 amps... There is an unaccounted for 0.1 amp?? If on shore power and no current is leaking into the water, currents on white plus green should equal current on the black. Is this just a resolution error on the meter (ie, resolution is only .1 amp).
Edit to add an interesting thing you brought up. If you put a current meter on a shore power cord (total cord, not individual wires), you can only tell if there is leakage into the water because the net return current will not match the source current. But if the ground fault is internal to the boat, putting the current meter on the the whole shore power cored wont show anything.. because the sum of green and white current will exactly match the black current. Ie, the net current in is still equal net current out so meter doesnt show anything.
FYI, I when I quickly looked at the OP numbers (below)
Black (power lead) 9.50 Amps
White (common) 9.15 Amps
Green (ground) 0.45 Amps
I had assumed that the current on the white and green (9.15 plus .45) exactly matched the current on the black (9.50)
But.. they dont exactly. The white and green add up to 9.6 amps... There is an unaccounted for 0.1 amp?? If on shore power and no current is leaking into the water, currents on white plus green should equal current on the black. Is this just a resolution error on the meter (ie, resolution is only .1 amp).
Edit to add an interesting thing you brought up. If you put a current meter on a shore power cord (total cord, not individual wires), you can only tell if there is leakage into the water because the net return current will not match the source current. But if the ground fault is internal to the boat, putting the current meter on the the whole shore power cored wont show anything.. because the sum of green and white current will exactly match the black current. Ie, the net current in is still equal net current out so meter doesnt show anything.
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