If a separately derived system has 600 kcmil copper secondary ungrounded phase conductors, what is the minimum required size for a copper system bonding jumper?

To determine the minimum required size for a copper system bonding jumper in a separately derived system with 600 kcmil copper secondary ungrounded phase conductors, it is important to consult the National Electrical Code (NEC). According to NEC Table 250.102(C)(1), the size of the bonding jumper must be based on the size of the grounded conductors or the largest ungrounded conductor of the system.

In this case, since the system is comprised of 600 kcmil copper conductors, the bonding jumper must be sized accordingly. For copper conductors, the NEC specifies that the bonding jumper should be sized at a minimum of 1/0 AWG copper for conductors that are larger than 250 kcmil. This minimum size ensures adequate conductivity to safely bond the system and mitigate any potential fault currents.

Thus, the choice of 1/0 AWG copper for the system bonding jumper is the correct answer as it meets the NEC requirements for the size of bonding jumpers for a system of this magnitude.