According to the regulations, metal braces used for box support must be protected against what?

Metal braces used for box support must be protected against corrosion to ensure their long-term integrity and functionality. Corrosion can occur due to various environmental factors, including exposure to moisture, chemicals, and other corrosive agents. When metal components are left unprotected, they can deteriorate over time, leading to weakened structural support that can compromise electrical boxes and associated wiring.

The National Electrical Code (NEC) recognizes the importance of using corrosion-resistant materials or protective coatings in environments that are prone to corrosion. This provision helps maintain the safety and reliability of the electrical installation, preventing potential hazards that could arise from compromised equipment.

In contrast, while moisture, impact, and rust are related to the overall protection of electrical installations, the specific emphasis on corrosion underscores the need to safeguard metallic components from degradation that could affect their strength and stability. Rusting, for example, is a form of corrosion that specifically refers to the oxidation of iron and steel, but the broader term "corrosion" encompasses various types of material degradation. Thus, focusing on corrosion protection is essential for ensuring the longevity and reliability of metal braces in electrical systems.