Cable Tray Connections for Electromagnetic Interference (EMI) Mitigation

Cable trays are used in industry to order cable runs in distributed systems. With little extra effort, cable trays can also be exploited to harden cables against external electromagnetic interference. Some recommendations in this regard are found both in literature and in standards. We critically examine the importance of cable tray end-connections to enclosures as well as their midspan connections. Emphasis is placed on visualizing common-mode currents and magnetic fields, which have bearing on the best type of connection to be used. Results are derived from computational electromagnetic analysis and network analyzer measurements on two models in a screened room. From this study, it is possible to give clear recommendations on best connection practice.