All metallic cable trays shall be grounded as required in Article 250. It instructs us on how to construct them, where to locate them, and how to stuff them with wires without using too much. Grounding and bonding are mandatory for metallic trays. Tray fill limits must be calculated properly. Mesh trays reduce installation time while. However, while wire mesh trays offer mechanical and thermal advantages, proper grounding and bonding are critical to ensure electrical safety, NEC compliance, and long-term system reliability. Steel is the most appropriate due to its ability to withstand melting when compared to aluminum in a way that it serves up to 90 minutes in wire protection. Grounding Properly. To comply with code requirements and ensure system safety, metallic trays must be electrically continuous, properly bonded at all splice points, and securely connected to the building's grounding system. 96 regardless of whether or not the cable tray is being used as an equipment grounding. Power circuit grounding of cable trays is explained in CTI Technical Bulletins, Titles No. 8, 11, and 12, and the National Electrical Code Sections 318-3-© and 318-7.
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