What is the minimum size for a copper bonding jumper if the secondary ungrounded phase conductors are 600 kcmil?

The minimum size for a copper bonding jumper is determined by the size of the ungrounded conductors it needs to bond. In this case, since the secondary ungrounded phase conductors are 600 kcmil, the bonding jumper must be adequately sized to ensure safety and proper functioning of the electrical system, compliant with the National Electrical Code (NEC).

For copper bonding jumpers connected to conductors of this size, the code stipulates specific sizing requirements. Generally, the minimum size for a bonding jumper that connects conductors of 600 kcmil is 1/0 AWG copper. This size provides sufficient conductivity to handle potential fault currents and maintain system integrity, ensuring reliable operation and safety.

Choosing a size smaller than 1/0 AWG, such as 2 AWG, 4 AWG, or 1 AWG, would not meet the necessary requirements for safety and performance in this application. Thus, selecting 1/0 AWG as the minimum size is essential for compliance and effective operation.