Fire-Retardant Cable Systems

The increasing use of nonmetallic cables in cable trays for industrial plant applications as recognized in the 1975 National Electrical Code, Article 340, mandates that these cables be suitable for this application and that the outer sheath be flame-retardant. The significance of various flame tests is discussed, and data obtained following procedures and modifications of IEEE Standard 383-1974, Section 2.5, are presented. It is evident that nonmetallic sheathed tray cables are available that will comply. Furthermore, when a flame-resistant jacket is applied over type ALS, MC, or AC armored assemblies, it results in an exceptionally rugged, corrosion, and flame-resistant nonpropagating construction.