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. Where cables pass through shafts, walls, slabs, or enter electrical panels or cabinets, openings shall be tightly sealed with firestopping materials in accordance with. Cable Trays have been permitted in the hazardous (classified) locations in the National Electrical Code for Class I (flammable vapor and gases) since the 1978 NEC and have been used extensively in chemical plants, refineries, and other types of facilities. This article is about code requirements. Let's break down what you need to know about explosion-proof requirements for cable trays in these environments, keeping it simple and clear. Chemical plants have risks like explosive gases, dusts, or vapors. UL Listed Systems Concrete Wall - C-AJ-4056 3 HR F-Rating, 3/4 HR T-Rating Gypsum. Cable trays seemed to run through fire rated barriers with reckless abandon; the holes created by passing the tray through the wall or floor varying in size and shape.
