This is an E-1 color code (formerly known as a K-1 code) because it includes both a white and green conductor. Per NEC guidelines, white is meant to serve as the neutral conductor, while green is only used to ground. Here's how the process unfolds: Cleaning: Remove oil, dust, and rust from the tray surface to ensure proper adhesion. Rust Removal: Use sandblasting, acid washing, or grinding to eliminate rust. The surface must reveal a clean metallic shine. As a result, this tray cable may not work for every situation. rcuits in commercial and industrial environments.