Connection between Building Ground Ring and Tower Ground Ring

• A. #4 AWG Copper in 1 point
• B. #2 AWG Copper in at least 2 points
• C. #1 AWG Copper in 3 points
• D. #2 AWG Aluminum in 2 points

Answer: (B)

Bonding the Building Ground Ring to the Tower Ground Ring creates one continuous, low-impedance path that keeps everything at the same electrical potential. This minimizes dangerous voltage differences during lightning, fault currents, or static discharge and helps protect both personnel and equipment.

The best practice is to use copper conductors of at least #2 AWG and make the connection in two or more independent points between the rings. Using two bonding paths provides redundancy—if one connection is damaged or degraded, the other still maintains the low-impedance link. Copper is preferred for its excellent conductivity and durability, and it resists corrosion better in these bonding applications.

Choosing a smaller conductor or a single bond would reduce the reliability and impedance performance, while using aluminum can introduce galvanic corrosion issues and is not the standard bonding practice in this context.