What is the minimum conductor size required when establishing a bond between electrical service equipment and structural steel?

The minimum conductor size required for bonding electrical service equipment to structural steel is determined by safety standards set forth in the National Electrical Code (NEC). The correct choice, #6 AWG copper or #4 AWG aluminum, is aligned with NEC Table 250.102(C) which specifies these conductor sizes for bonding purposes, ensuring that the bond is capable of carrying fault current effectively.

Using #6 AWG copper provides sufficient current-carrying capacity while also facilitating effective grounding and bonding. In cases where aluminum is used instead, #4 AWG is specified, as aluminum conductors generally require a larger size to carry the same current as copper due to its lower conductivity.

This standard is critical for maintaining safety and preventing electric shock or fires by ensuring that there is a reliable path to ground in the event of a fault. Conductors smaller than those specified may not provide adequate protection, increasing the risk of equipment damage or danger to personnel.