Cable trays do not always need to be bridged, but metal trays often require grounding connections to ensure electrical continuity and safety.

General Guidelines

For galvanized steel cable trays, bridging is not strictly required at the ends of connecting plates; however, each connection should have at least two fixing bolts with anti-loosening nuts or washers to maintain mechanical stability . For stainless steel and aluminum alloy trays, dedicated grounding bolt holes must be used to achieve proper conductive bridging between sections . This ensures that the tray system maintains electrical continuity and can safely carry fault currents if necessary.

Connection Methods

• Galvanized trays: Use at least two sets of galvanized steel bolts with anti-loosening gaskets for conductive connections, or insulated multi-strand copper wires with crimped tinned copper connectors (cross-sectional area ≥ 4.0 mm²) for bridging .
• Stainless steel/aluminum trays: Use special grounding bolt holes; avoid using bridge connection plates to fix bolt holes .
• Crimping: Wire ends should be crimped with copper or tin-plated copper connectors, secured with galvanized steel bolts and anti-loosening washers .

Support and Grounding Considerations

Cable tray supports should provide sufficient strength for the load and allow for future cable additions . Electrical continuity between trays is recommended, and the system should be grounded to structural steel at intervals of at least 18 meters . This ensures both mechanical stability and electrical safety.

Practical Recommendations

• When purchasing trays, request anti-loosening nuts for connecting bolts rather than washers for easier installation and maintenance .
• Ensure that all conductive connections are properly crimped or bolted to maintain grounding integrity.
• Plan for future expansion by leaving adequate space and considering additional load requirements . In summary, bridging is material-dependent: galvanized trays may not require electrical bridging at every connection, while stainless steel and aluminum trays require dedicated grounding connections. Proper installation with anti-loosening hardware and crimped connections ensures both mechanical and electrical safety.