Which bonding method should be used for tower structure ground conductors unless directed otherwise by the manufacturer?

• A. Irreversible High Compression
• B. Exothermic bonding
• C. Solder
• D. Welding

Answer: (B)

Exothermic bonding is used for tower structure ground connections because it creates a strong, continuous metallurgical bond right at the joint without needing external heat or power sources. The thermite reaction fuses the bonding conductor directly to the tower members, forming a durable, corrosion-resistant connection that can handle outdoor exposure, vibration, and temperature changes typical of tall structures. This method is especially practical in the field on large conductors and mixed metals, providing a reliable electrical path with low impedance.

Other methods have drawbacks in this context. Solder requires significant heat and careful control, making it impractical for large ground conductors and field-installed tower components. Welding can introduce distortion or be difficult to perform safely on existing structures with coatings or on certain metal alloys. Irreversible high compression relies on clamping forces and surface cleanliness; it may not offer the same long-term reliability in harsh outdoor conditions.

Therefore, unless the manufacturer directs otherwise, exothermic bonding is the preferred approach for bonding tower structure ground conductors due to its robustness, field-compatibility, and durable electrical performance.