"The U.S. Bureau of Mines investigated the operational characteristics of spliced portable power cables. This research had a dual purpose: (1) to determine the thermal and mechanical performance of repaired trailing cables and compare them to undamaged cables, and (2) to gauge the impact of long-term, localized heating on the insulating and jacketing materials contained in the Mine Safety and Health Administration (MSHA) accepted or approved cable splice kits. The range of splice joint resistance and tensile breaking strength was first determined from laboratory measurements. The choice of crimping tools affected the strength of the splice under tension. Next, thermal profiles of energized spliced cables were constructed. Spliced conductor joints were found to operate 5 to 20 C hotter than the intact cable at rated currents. Finally, samples of splice kit insulation and jacket materials were subjected to accelerated life tests. Thermal aging of these materials confirmed a deficiency in the thermal rating of the insulating tape. The recommendations may be utilized to revise splice kit design, splice kit approval criteria, and trailing cable loading guidelines." - NIOSHTIC-2 NIOSHTIC no. 20039202

National Institute for Occupational Safety and Health