Since the GEC can be connected to the grounded conductor at any point between the load end of the service drop or lateral to the bonded neutral buss in the service disconnecting means I see no problem with connecting the GEC at the service head. Back when I was doing rural work we would always have a rod at the yard pole were the meter was located in order to ground the grounded conductor at that point. That was done to make the overhead wires cope with lightning more effectively. The rods we were using were sectional and were driven with an air hammer. The rod at the meter was always tested with a three pole ground impedance tester. I can never remember needing more than two rod sections in order to pass the test.
When I was in the air force I helped a work party ground fire alarm boxes for ground return signaling. The NCO in charge told me he had one installation that took five sections to get the box a reliable signal pathway. If I remember correctly the signal current was four tenths of an amp. The voltage on those circuits was forty eight volts DC.
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Tom
Grounding Service-Supplied Alternating-Current Systems.
(a) System Grounding Connections. A premises wiring system that is supplied by an ac service that is grounded shall have at each service a grounding electrode conductor connected to a grounding electrode that complies with Part H of Article 250. The grounding electrode conductor shall be connected to the grounded service conductor at any accessible point from the load end of the service drop or service lateral to and including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means. Where the transformer supplying the service is located outside the building, at least one additional grounding connection shall be made from the grounded service conductor to a grounding electrode, either at the transformer or elsewhere outside the building. A grounding connection shall not be made to any grounded circuit conductor on the load side of the service disconnecting means.
