When cable trays pass through walls or floors, seal openings using fire-rated penetration sealing materials. Do not modify or damage the tray coating or structure during use. Main. This publication is intended as a practical guide for the proper and safe* installation of cable ladder systems, cable tray systems, channel support systems and associated supports. Channel tray can protect against electromagnetic inte, is a welded wire-mesh cable management system made of high-strength steel wire. This article provides an in-depth. These rules have to be respected scrupulously by the engineering services, consulting firms, the fitters (external companies, employees of the technical services or employees of the maintenance services, the laboratory agents) implementing or working on cabling systems in the ITER facility during.