Which bonding methods are allowed for the Tower Ground Bus Bar?

• A. Soldered joints only
• B. Exothermic, irreversible compression or listed two-hole compression lugs; jacketed conductor
• C. Mechanical clamps only
• D. Welding with copper filler

Answer: (B)

Bonding for the Tower Ground Bus Bar must be a permanent, low-impedance, weatherproof connection that can withstand outdoor vibration and corrosion. The allowed methods cover approaches that are proven to be reliable in these conditions: exothermic welding creates a continuous metallurgical bond between conductor and bus bar, yielding a single, uninterrupted path that resists loosening and corrosion. Irreversible compression or listed two-hole compression lugs provide a field-installable, tamper-resistant connection that stays tight through temperature changes and vibration, with the added assurance of UL-listed compatibility for grounding conductors. Using jacketed conductor with these lugs protects the joint from moisture and mechanical wear, helping maintain long-term integrity. In contrast, methods like soldered joints, purely mechanical clamps, or welding with copper filler don’t meet the same durability or listing requirements for outdoor grounding hardware, making them unsuitable for this application.