Mike Dolt Enterprises
Mike Dolt Enterprises
User: mshields, Location: Boston, MA
Asked on: Tuesday, April 5, 2011 at 9:17 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:49 am EDT
Question: I've specified that a length of 12 year old shielded EPR 15kV Okonite cable be removed such that this feeder can go to a new switchgear lineup via a splice and a new length of cable. i.e. the feeder now goes to a 30 year old S&C switchgear and I'm rerouting it to a brand new lineup.The EC would like to pull this 50 feet of cable out by hand and reinstall it. He believes there is sufficient length to do so. He also contends that avoiding a splice will provide for a more reliable installation.I think I'd rather have the splice and have the length of cable running in the new duckbank to the new gear be a brand new length of cable. I have always heard that splices when done right are more reliable than the cable itself. I'd be curious for your collective input/experience. If by chance you know of any articles on the subject, all the better.Thanks,Mike
Reliability Considerations Properly made splices
When executed correctly, splices can indeed be more reliable than the original cable. Splices eliminate potential weak points in the cable, which can arise from aging, damage, or manufacturing defects.
Benefits of new cable
A new length of cable can provide peace of mind as it is free from previous wear and tear or potential defects. However, it also introduces a new point of connection (i.e., the splice) that could potentially become a source of problems in the future.
Aging of existing cable
The 12-year-old shielded EPR 15 kV Okonite cable has been in service for a considerable time, and its insulation and shielding properties may have deteriorated. Replacing a portion of this cable with new material could improve the overall reliability of the system.
Practical Considerations Availability of slack cable
It is crucial to verify if there is truly sufficient slack cable to allow for the removal and reinstallation of 50 feet of cable by hand. This requires careful on-site assessment and measurements.
Feasibility of a splice
If there is insufficient slack cable, a splice may be the only viable option. In such cases, having a skilled electrician make a reliable splice is essential.
Recommendations
Based on the available information, the following recommendations are made: If there is sufficient slack cable to remove and reinstall 50 feet by hand and the EC is confident in their ability to do so safely and reliably, it could be a viable option to avoid a splice. However, if there is any doubt about the availability of slack cable or the reliability of the EC's proposed hand-pulling method, it is strongly recommended to splice in a new length of cable. A properly made splice should not compromise the reliability of the system and may provide advantages over a longer length of aged cable.
Articles on the Subject [Reliability of Spliced Medium Voltage Cables](https://www.researchgate.net/publication/345730119_Reliability_of_Spliced_Medium_Voltage_Cables) [Splicing of Medium Voltage Underground Distribution Cables](https://www.teconex.com/resources/white-papers/splicing-of-medium-voltage-underground-distribution-cables)* [Splicing Power Cables: Best Practices for Reliability and Performance](https://ecmweb.com/design/article/21583382/splicing-power-cables-best-practices-for-reliability-and-performance) Flag for review