UL 13:2005 pdf download – Power-Limited Circuit Cables
UL 13:2005 pdf download – Power-Limited Circuit Cables.
18 Cold Bend Test of Insulation
18.1 After being Conditioned for 4 h in circulating air that is pecoofed to and maintained at a temperature of —20.0°C. +3.0°C. —2.0°C (—4.0°F. +5.4°F, —16°F’), the insulation or integral insulation and jacket on specimens removed from the finished cable (before being conditioned) shall not crack on the inside or outside surface when the specimens are individually wound onto a round mandrel in the cold chamber as described in 18.2 — 18.4.
18.2 A circular metal mandrel is to be used in this test The diameter of the mandrel is to be as indicated in Table 18.1. The single mandrel is to be securely mounted in the chamber in a position that facilitates the winding.
18.3 For testing unjacketed ribbon cable or the integral insulation and jacket of flat cable. 24-inches or
61 0-mm lengths of the complete ribbon or flat cable are to be used as flat specimens. The insulated conductors, wires, and any other coaxial members are to be removed from a 24-inch or 610-mm length of other finished cable and are to be separated from one another and individually placed as round specimens in the precooled Cold chamber. Any jacket and the shield(s) are to be removed from coaxial members before these members are placed in the cold chamber. The specimens and mandrel are to be conditioned for 4 h in circulating air that is precooled to and maintained at a temperature of —20.0°C +3.01—2.0°C (—4.0°F +5.41—3.6°F). At the end of the fourth hour, the specimens are to be wound individually, and in quick succession, for 5 full turns onto the mandrel, with adjacent turns touching (1 complete turn is to be used f or flat cable), The winding of each specimen is to be at an approximately uniform rate of 5 seconds per turn. The winding is to be done in the cold chamber.
18.3 revised Februasy 29. 1996
18.4 With a minimum of handling and while remaining in the coiled form, each specimen is to be slid from the mandrel, removed from the test chamber, and placed on a horizontal surface. The specimens are to rest on that surface undisturbed for at least 60 mm in still air to warm to a room temperature of 24.0 ±8.0°C (75.2 ±14.4°F). Each specimen Is then to be examined tot cracking on the inside and outside surfaces of the insulation or of the integral insulation and jacket. Cracks on the inside surface can be detected as circumferentiat depressions in the outer surface of a specimen of material other than a fluoropolymer. Circumferential depressions in a fluoropolymer surface are likely to be yield marks (locally stronger points) rather than indicators of cracking.
19A.1 Type PLTC cable marked -ER as indicated in 40.1 and 41.1 [NEC 725.61(D)(4)J shall be capable of withstanding without contact between circuit conductors, and without contact between a circuit conductor and any shield, the energy of a free-falling, flat-faced weight that impacts the cable at the point at which the cable is laid over a steel rod. The test shall be conducted and the results evaluated as described in 19A.2 — 19A10. Flat cable shall be capable of withstanding the impact when tested with the broad and narrow faces laid over the rod (flatwise and edgewise using separate specimens).
Revised 19A.I eectrve May 29, 2006
19A2 The results ot this test, conducted on a finished cable containing three circuit conductors that are of identical size, are to be taken as representative of the performance of all other cables of the same construction containing the same or a larger number of conductors of the same or of a larger size. The performance of a two conductor cable is to be tested on a finished cable containing two circuit conductors that are of identical size and shall be taken as representative of the performance of al other cables of the same construction containing the same or a larger number of conductors of the same or of a larger size. The performance of the cabled conductors in a round cable is to be considered representative of performance of those conductors in both round and flat cables.
19A.3 A solid rectangular block of steel 4—3/4 inches or 121 mm long by 3 inches or 76 mm wide by 5 inch or 127mm high, with its upper face (4—3/4 by 3 inches or 121 by 76mm) horizontal, is to be secured to a concrete floor, the building framework, or another solid support. A solid steel rod 3)4 rich or 19 mm in diameter and 4—3/4 inches or 121 mm long is to be bolted or otherwise secured to the upper face of the stationary block with the longitudinal axis of the rod in the same vertical plane as the longitudinal axis of the stationary block.
19A.4 An impact weight of 10 lb or 4.54 kg is to be used and shall consist of a solid rectangular block of steel with its lower face (the face that strikes the cable) 2 inches or 51 mm wide and 6 inches or 152 mm long. The edges of the lower face are to be rounded to a radius of 1/16 inch cx 1.5 mm.