Journeyman Lineman (JL) Verbal Practice Test 2026 - Free Journeyman Lineman Sample Questions and Study Guide

The ability of a protective ground to carry current depends on its conductor size—the larger the wire, the higher its ampacity. The grounding conductor is sized to carry fault current long enough for the protective device to trip, so bigger conductors can handle more current without overheating. Among the options, 4/0 copper has the largest cross-sectional area, giving it the highest ampacity (about 400 A in the provided rating). The smaller conductors—#2 copper (200 A), 2/0 copper (300 A), and 1/0 copper (250 A)—have lower ampacities, so they can carry less current continuously.