Journeyman Electrician Practice Exam 2026 - Free Electrician Practice Questions and Study Guide

The ampacity of a size 8 AWG single copper conductor is determined by various factors, including the conductor's size, material, insulation type, and its installation conditions. For a size 8 AWG copper conductor with Type FEPB insulation, installed in free air, the ampacity can be referenced from the National Electrical Code (NEC) tables.

When copper conductors are installed in free air, they can usually carry more current compared to those installed in conduit or other configurations. Specifically, Type FEPB insulation is rated to handle higher temperatures, which allows the conductor to safely carry an increased load.

According to NEC guidelines, a size 8 AWG copper conductor with the specified insulation type, under free air conditions, can typically carry 80 amperes. However, depending on the referencing guide or regional amendments, it may be calculated or rounded to 90 amperes in specific scenarios, but the most common referenced value for practical purposes remains around 80 amperes.

Thus, understanding the insulation type and installation method, along with the proper source references, contributes to determining the correct ampacity value for this conductor setup.