Cable edge test

Cables pass the test if, when they are wiped clean after burning has ceased, the charred or affected portion has not exceeded 2.5 m above the bottom edge of the burner. 

Another variant of these tests concerns resistance to fire with mechanical shock. A 1200 mm long sample of cable is mounted onto a vertical wall (Fig. 3.128). The cable is ignited by a gas burner system located at the bottom of the wall while a steel bar pivoted near the upper edge of the wall strikes the top of the wall at its midpoint once every 30 s. The cable complies with the requirements of the standard if no fuse is ruptured during the 15-min period of test. Cable is rated according to the flame temperature of the gas burner as follows ... 

It is important to check the extensometer knife edges for damage and to ensure that no additional load is applied by the weight of the extensometer cable, which is best supported with a magnetic clip attached to the metal frame of the testing machine. If wedge action grips are used, make certain that the shear pins are intact. 

Some of the telecommunication cable plant components are made with met2ils embedded in polymers, and the metals are exposed to the corrosive environment only at very small areas (e.g., edges or sm2dl defect sites on the polymer). Test methods are used to ev duate the penetrability of the metal-to-polymer interface and the ensuing progressive corrosion of the metal. 

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