12 Power-Cable Installation Mistakes

Nearly half of all cable-related outages can be traced to these 12 common installation mistakes.

By Mark Franks, AVO Training Institute

It’s been estimated that approximately 15% to 20% of U.S. electrical distribution is underground—with approximately 40% of these installations at or near the end of their projected 40-yr. service lives. Many of these systems have already experienced failures, been repaired, and returned to service, only to fail again. The adverse effect on costs and reliability of North America’s power grid is enormous.

Studies have found that approximately 50% of all cable-related outages can be attributed to failed splices and terminations, a majority of which are directly related to poor workmanship during the installation. A significant number can be attributed to mishandling of the cable during the installation process, either in direct-bury or duct applications.

These statistics come as no surprise to the training industry. Similar skill-related issues exist in other crafts. As with other sectors, advanced technologies (in this case, improved materials-engineering and cable design) haven’t able been to overcome the “human effect.” The sad fact for electric-power distributors and users alike is that even the highest-quality cable in the world, installed in a protected environment, will fail prematurely if it’s spliced by a worker who hasn’t received proper training. Consider the following “Dirty Dozen” list of common cable-installation mistakes.

Installation Mistakes

• Excessive tension during cable pulling, causing separation of cable components, shield damage, and jacket failure.
• Cuts in cable due to protrusions or debris in the duct system.
• Rocks in the backfill of direct-bury cable.
• Exceeding the minimum-bending radius of cable during installation.

Splicing Mistakes

• Not following critical-dimension instructions during prepping or assembly.
• Not cleaning insulation surfaces or allowing contamination during splicing operation.
• Improper crimping of dies, number of crimps, or sharp protrusions on connector sleeve after crimping.
• Longitudinal and radial cuts through semi-conductive insulation shield, causing insulation failure.

Termination Mistakes

• Not following instructions for critical dimensions during preparation.
• Not installing proper seals to resist outside moisture.
• Not cleaning insulation surfaces, allowing contamination during termination.
• Longitudinal and radial cuts through semiconductive insulation shield, causing insulation failure.

Every item on this list points to a lack of worker training and/or tooling issues during splicing. Without concerted efforts to provide comprehensive hands-on skills training, reinforced by accomplished mentors on the job, this list and the outages it spawns will continue to plague the electric-power-distribution sector and the customers it serves. Training and certification of cable-installation personnel is crucial in assuring the quality of their work, as well as the reliability of the systems and processes that work supports. MT

To learn more about power-cable installation and other electrical-training topics and services, visit avotraining.com.