Several grounding points for communication tower feeder lines

Communication tower feeder lines should be grounded at multiple points along the tower, with proper bonding to the tower and grounding electrodes to ensure safety and lightning protection. Key Grounding Practices1. Grounding at the Antenna and Tower Base All coaxial cables, waveguides, and antennas should be bonded to the tower near the antenna base and again near the tower base before routing toward the equipment shelter or ice bridge.

This ensures that any lightning-induced currents are safely diverted to the tower structure rather than sensitive equipment. 2. Multiple Grounding Points Along the Tower For towers over 100 feet, cables should be bonded to the tower at intervals not exceeding 75 feet.

This prevents high-voltage surges from traveling down the cable and protects both the feeder lines and connected electronics. 3.

Grounding Wire Specifications

Use #6 AWG minimum tinned copper wire for coaxial cable grounding. For tower-to-ground connections, use #2 AWG bare tinned solid copper wire or 1/0 AWG bare tinned stranded copper wire for ground rings. Exothermic welds are recommended for below-grade bonding, though irreversible fittings or pressure connections may be used if welding is prohibited.

4. Grounding Electrodes and Spacing Each tower leg should connect to a standard grounding electrode, with a minimum of three electrodes per tower. Electrodes should be spaced at least 6 feet apart, ideally twice the length of the ground rod, and connected via a buried ground ring at least 2.

5 feet below the surface and frost line. 5.

Bonding to Tower and Equipment Grounds

Cable grounds should be bonded to a grounding bus bar near the tower base, which is then bonded to the tower ground. The tower grounding system should be integrated with all other grounding systems within the compound to maintain a single electrical potential. Feeder shields, PoE lines, Cat6 cables, and waveguides should be bonded to the tower or feeder tray near the antenna to handle lightning currents safely.

6.

Resistance Targets

For general tower grounding, resistance to earth should not exceed 25 ohms. For critical equipment, a resistance of less than 5 ohms is recommended, which may require supplemental grounding and extensive below-grade electrodes.

Summary

Proper grounding of communication tower feeder lines involves multiple bonding points along the tower, adequate wire sizing, ground electrodes with correct spacing, and integration with the tower and equipment shelter grounding systems. These measures protect personnel, prevent equipment damage, and ensure reliable operation during lightning events or electrical surges.