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. The effective weatherproofing of cable trays helps to keep weather out, preventing damage to the building envelope, avoiding thermal breaks, maintaining the indoor environment and helping to keep the various cables and wires protected. The last part of our penetration seal series of articles. Cable tray installation must comply with specific technical standards to ensure electrical safety, system reliability, and long-term maintainability. Route. the roxtec sealing system for cables and pipes protects against fire – but also against gas, water, and several other risk factors.