Summary
Highlights
The speaker initially discusses significant proposed changes to Article 310, specifically 310.3A, for the 2023 NEC. These proposals aimed to introduce 16-gauge copper and 14-gauge copper-clad aluminum for branch circuit wiring. Although this would have been an industry-changing alteration, these specific changes did not pass in the 2023 code cycle, though there's a possibility they could be adopted in later cycles (2026 or 2029).
Despite the major proposed changes not passing, some important updates were made in Article 310. The primary change was the addition of specific requirements for copper-clad aluminum conductors in 310.3. The speaker emphasizes the importance of understanding copper-clad aluminum, even if one doesn't personally use it, as it's a valid and increasingly used product in the field.
The new requirements stipulate that solid aluminum conductors (8, 10, or 12 gauge) and stranded aluminum conductors (8 gauge through 1000 kcmil) must utilize a AA-8000 series aluminum alloy. For copper-clad aluminum, the conductor must be at least 10% copper, and its aluminum core must also be a AA-8000 series aluminum alloy.
The speaker explains the manufacturing process of copper-clad aluminum, highlighting how the aluminum core is metallurgically bonded with copper in a controlled, oxygen-free environment. This process prevents the formation of aluminum oxide, which is an insulator and the primary concern with standard aluminum terminations, thereby eliminating termination issues typically associated with aluminum wire.
A significant addition is the requirement that copper-clad aluminum conductors must be listed. Unlike copper or pure aluminum conductors, which do not have a universal listing requirement, the more involved manufacturing process of copper-clad aluminum necessitates listing to ensure it meets all product standard test requirements. This applies to individual conductors, such as XHHW or THWN, used in conduits, distinct from listed cable assemblies like NM cable.