What is the minimum-size bonding jumper required between the communications grounding electrode and power grounding electrode system in a commercial building?

The minimum-size bonding jumper required between the communications grounding electrode and the power grounding electrode system in a commercial building is specified as 6 AWG. This requirement is established to ensure that there is adequate conductivity and safety in the bonding connection between the two grounding systems.

Using a bonding jumper of sufficient size is crucial to minimize the risk of hazardous voltages occurring under fault conditions, as well as to ensure the effective operation of overcurrent protective devices. The 6 AWG size is recognized as adequate for carrying fault current and providing a reliable bond that will help in grounding systems functioning effectively together.

In contrast, while other sizes like 4 AWG or 8 AWG may be stronger, they exceed the minimum requirement established for safety and practicality. Meanwhile, a size of 10 AWG does not meet the necessary criteria for proper bonding and might not provide adequate protection, as it could potentially be insufficient in a fault scenario. Therefore, using 6 AWG ensures both compliance with electrical codes and adequate safety measures.