TC-ER-rated cables can be installed in exposed runs outside the cable tray, up to 6 feet between the cable tray and connected equipment, and without conduit—provided that the cable is secured and protected from mechanical damage, per code. When planning a modern electrical system for industry, utilities or commercial spaces, the question “Do tray cables need to be in conduit?” naturally comes up. It helps prevent overheating, mechanical damage, electromagnetic interference, and allows for future expansion. As opposed to conduit, cable trays are open trays on and along which bundles of cables can be arranged and laid.