What is the minimum size required for the bonding conductor that connects the grounding electrode systems for DC and AC sides if the DC side uses 6 AWG copper?

The minimum bonding conductor size required to connect the grounding electrode systems for both the DC and AC sides is determined by the size of the existing conductors. In this case, because the DC side utilizes a 6 AWG copper conductor, the bonding conductor must be appropriately sized to ensure effectiveness and safety.

According to the National Electrical Code (NEC) and grounding practices, when connecting different systems, the bonding conductor must be sized based on the largest conductor in the system. For a 6 AWG copper conductor, the appropriate bonding conductor size that meets both code and safety requirements is 1 AWG copper. This size ensures that the bonding conductor is capable of carrying potential fault currents without overheating, maintaining the integrity and performance of the grounding system.

Using a conductor that is too small could lead to unsafe conditions, including excessive voltage drop or inability to conduct fault currents efficiently. Thus, a 1 AWG conductor is the correct choice for connecting grounding electrode systems for both the AC and DC sides, ensuring compliance with electrical standards and promoting safety.