A #12-4 type SO cord is used to supply a portable 120/240 volt, single-phase, incandesant lighting load. One conductor is the ground conductor. One conductor carrys only the unbalanced circuit current. What is the ampacity of the ungrounded conductor?

A #12-4 type SO cord is used to supply a portable 120/240 volt, single-phase, incandesant lighting load. One conductor is the ground conductor. One conductor carrys only the unbalanced circuit current. What is the ampacity of the ungrounded conductor?