Case Study

Identifying Workmanship Issues with Factory Grade® Technology

Contractor Workmanship Feedback with IMCORP Factory Grade® Technology

OVERVIEW
Workmanship issues are identified with the Factory Grade® technology.
CHALLENGE
Identifying other accessories with workmanship issues on failed cable system.
RESULTS IMCORP’s
Factory Grade® technology provides critical feedback to utility client trainers and installers.

A utility client requested IMCORP to assist with a dissection and the identification of the root cause of an in-service joint failure on a critical 1000kcmil feeder. Based on the evidence received, the root cause was identified as insulation damage from an overheating connector as a result of improper crimping and little to no wire-brushing of the oxide on the outer aluminum conductor strands. In addition, the investigation revealed cable preparation issues such as jagged/non- radial cable semicon cutbacks. These findings raised concerns about the workmanship quality of recent repairs and the rest of the cable system. As a quality check the utility client had been using our Factory Grade® assessment extensively on their aging residential cable systems and decided to employ the technology as a quality control measure. The results of the assessment  indicated multiple joints throughout the cable system were failing to meet the accessory manufacturer’s minimum performance standards.
 
The utility client asked us to perform a dissection and root cause analysis on some of the substandard joints. The dissection showed systemic workmanship defects including knife cuts in the cable insulation and non-radial/jagged semicon cutbacks (see examples in Figure1).
 
By partnering with IMCORP, the utility’s engineers were able to provide  immediate feedback to their trainers and the installation crews on precisely where to focus training and how to recognize and fix common errors during the installation process. The joints were re-assessed and our Factory Grade® technology verified that the entire cable system met the cable and accessory manufacturer’s performance standards.
  Figure 1: Dissection of the premolded joints shows non-radial and jagged cutbacks (left, red circle) creating stress-enhancements. Knife cuts into the cable insulation at the semicon cutbacks (right, red circle), creating voids and stress enhancements at some of the most critical points of the joint/cable interface

LEADERSHIP

THE STANDARD IN POWER CABLE RELIABILITY