Perforated Cable Trays allow effective air circulation, dissipating heat to prevent insulation damage and electrical failures. Raceways, on the other hand, provide enclosed pathways to protect wiring from external influences, while maintaining ventilation. This makes it hard for the heat produced by the cables to escape. Environmental Factors: How hot or humid the air is, and how well air moves around, also affects how well cables cool down. Fiberglass cable tray loses 10% of its rated strength at temperatures as low as 100°F. Heat is an inherent byproduct of electrical currents flowing through cables, and in industrial settings, where cables often carry substantial. How to Avoid Severe Heating of Metal Cable Trays The eddy currents from AC power cables induced in the metallic tray generate additional heat.