Why does a electric meter need a ground wire?
Residential power uses a common “Neutral/ground” lead. Your service wires connecting from the meter box to the main panel should have a ground conductor which is attached to the ground bus in the main panel and bonded to neutral. Its possible that the ground rod was installed near the main panel rather than the meter socket. The bare copper ground wire is for safety and to ensure a low resistance current pathway back to the circuit breaker or fuse. The idea is the a fault from a hot lead to a receptacle or switch box for example will find a pathway of sufficient current carrying capacity back to the fuse/CB panel that will trip the circuit. If this ground (bonding) lead did not exist than you might receive a shock if you were to touch the metal box with an insulation fault. Using the Earth as a ground (via the copper rod driven into the soil) provides a pathway for lightning or an accidental high voltage spike to discharge to. (Like a car hitting a pole and a high voltage line crosses
