Grounding frequency for 6M and 6.6M is eight times per mile.

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The important point is how often you establish a solid grounding path along an outdoor route to keep potential differences low and provide a reliable return path for fault currents and static discharge. For 6M and 6.6M installations, the standard specifies eight grounding points per mile.

This spacing keeps the impedance of the grounding system low and helps ensure that any fault current or transient (like lightning or EMI) has a quick, direct path to ground, reducing voltage rise along the route. Eight per mile translates to roughly every 0.125 miles (about 660 feet), aligning with typical placements of handholes, pedestals, or other bonding points along an outdoor span. If you spread grounding points farther apart, impedance rises and the system won’t clamp voltages as effectively, which is why the eight-per-mile requirement is the best choice here.