Evaluation and Acceptance Criteria for Innovations in Explosionproof Electrical Enclosures

摘要

A conventional trailing cable connection box on a continuous mining machine was modified by the addition of two innovative devices: A pressure vent to preclude buildup of high pressure caused by an explosion inside the enclosure and a grommet-type cable entry to simplify and speedup cable entering procedures. The devices were evaluated for 8-1/2 months in a working section of an underground coal mine. Laboratory tests before and after the in-mine exposure show no measureable change in the devices. Following the favorable in-mine evaluation, technical performance criteria were defined to serve as the basis of approval for the use of the devices. Additional tests to measure comparable gripping of the cable by asbestos rope, substitution rope materials, and by the urethane grommet-type entry were included in the effort.