Evaluation of crimped terminations and splices in in-wall electric heaters

This study evaluates crimp wire terminations and splices in new in-wall electrical heaters, which are permanently installed for room heating in homes. Crimped wire terminations and splices are generally used for the internal wiring, with current flow up to about 15 A. Burnout failures of the crimp terminations have been investigated in field samples of these heaters. The results of this study of crimp terminations from new heaters reflect a wide quality variation. Some defects are noted on visual examination. Connection resistance measurements show a range of more than two orders of magnitude. Cross-sections of samples of relatively high-resistance crimps show that the wires are not adequately compacted in the terminals. The results of this study indicate that many of the field failures are attributable to deficiencies that are intrinsic to the crimp terminations when new. Improvement of both the applicable industry standards and the manufacturing quality assurance methods are discussed.