Cable trays require serrated washers

Serrated washers are generally not required for cable trays and are often prohibited by standards like NORSOK; alternative fastening methods such as self-locking flange nuts are recommended.Use of Serrated WashersSerrated washers, also known as 'shake-proof' washers, are designed to prevent loosening due to vibration and thermal effects. They are commonly used with cable glands and locknuts to maintain mechanical stability and electrical continuity, especially in harsh industrial or offshore environments . Their internal teeth bite into metal surfaces, enhancing conductivity and preventing inadvertent loosening caused by vibration .Cable Tray InstallationsFor cable trays and ladders, industry standards such as NORSOK explicitly prohibit the use of star-shaped or serrated washers. Instead, these standards recommend using A4 self-locking flange nuts or other approved fastening methods to ensure secure and compliant installations . This is because serrated washers can damage the tray surface or compromise mechanical integrity in large-scale tray systems.SummarySerrated washers: Useful for cable glands, anti-vibration, and grounding in equipment, but not suitable for cable trays.Cable tray fastening: Follow standards like NORSOK, using self-locking nuts or flange nuts instead of serrated washers.Material considerations: When used elsewhere, serrated washers are typically made from AISI 316 stainless steel for corrosion resistance and durability .In conclusion, while serrated washers are valuable for certain electrical connections, they are not required and often prohibited for cable tray installations, and compliant fastening methods should be used to meet safety and regulatory standards.