080620-2016 EST
Between poles are there one or two primary wires. If there is only one primary wire between the poles, then the earth or a wire in the earth has to be the other side of the primary circuit. Note: also the primary neutral wire my be the same wire as your low voltage secondary neutral wire. This will be bundled with the hot wires to all the houses supplied by your transformer. Then it will continue on and connect with the next transformer's secondary and primary neutral.
Put a probe in the ground, use a screwdriver, at your transformer pole. If the earth is being used as one conductor for the primary, then you will see a substantial voltage gradient as you move away from your transformer pole. Be careful. Use insulated probes and maybe other protective means. Put another probe 10 ft away from the first and below your primary power line. Measure the voltage difference. If this is millivolts, then there is not much ground current. If volts over this short range, then be very careful.
The extension wire from probe 1 to your voltmeter at probe 2 needs to be insulated.
Move the second probe further away in the same direction along and under the primary wire. Your results will determine how far you separate the probes, and your safety concerns.
Report back.
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