Are All Types Of Cable Terminations The Same?
Published 16 Oct 2022
Cable Terminations
3M Cold Shrink
Guest Article by 3M Electrical
From lost time to repairs, cable failure can result in costly power outages. Often, these failures are the result of electrical stress.
Improper cable termination stress control can result in premature electrical aging and can lead to failures. It can also present risk to the overall safety and reliability of a utility distribution system, windfarm, or heavy industrial facility.
The question is are all cold shrink terminations equal? Not necessarily. Test results indicate this is not the case, taking stress control into consideration. Learn more about Geometric and High-K stress relief, the differences between them, and how test results show better performance with 3M’s method of using High-K stress relief.
Managing electrical stress comes down to design.
I’ve noticed when meeting with customers that there is a consensus that all types of cable terminations are equal. That’s simply not the case. Just because cable termination accessories may look similar, it doesn’t mean they perform the same.
To help dispel this myth, we ran our own study comparing our own 3M™ Cold Shrink Termination technology, which leverages capacitive stress control versus geometric stress cones. Here’s what we found.
Capacitive stress control vs. geometric stress cone: what’s the difference?
A test was conducted in a controlled laboratory environment to determine which method is most effective at controlling electrical stress. As part of our study, we looked at the performance difference between two common types of cable terminations:
1. Geometric Stress Cone: This is an electrical stress control method aimed at reducing stress at the shield discontinuity. It works by extending the shield and gradually increasing the thickness of insulation under it.
2. Capacitive Stress Control: This is a high dielectric constant (Hi-K) stress control method that controls the stress at the end of the insulation shield. It lowers the electrical stress at the point of shield discontinuity by diverting the electrical stress along the cable insulation interface.
The comparison: 3M™ Cold Shrink Products that use Hi-K capacitive stress control versus competitive cold shrink products that use geometric stress control.
For the interfaces’ stress control method, we chose our own 3M™ Cold Shrink QT-III Termination. It’s designed to spread the electrical stress lines, which helps to reduce the surface stress, resulting in improved termination performance and overall cable life expectancy.*
After putting both methods through several tests in the 3M lab, the results yielded three key benefits.
Performance Testing of Cable Terminations
| Product | Stress Control Technology |
Partial Discharge |
1 Minute AC Withstand |
15 Minute DC Withstand |
BIL (10+/- Surges) |
HOT BIL (10+/- Surges) |
Partial Discharge |
5 Hour AC Withstand |
5 Minute AC Withstand |
BIL (10+/- Surges) |
Partial Discharge |
| Competitive Sample 2, 3, 4 |
Geometric | X | X | Cannot Test further. Samples failed. | |||||||
| Competitive Sample 5 |
Geometric | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | X | Cannot Test further. Sample failed. | ||
| Competitive Sample 6 |
Geometric | X | ✓ | ✓ | ✓ | ✓ | X | X | Cannot Test further. Sample failed. | ||
 (4 Samples) |
Hi-K | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Performance results
capacitive stress control vs. geometric stress cone study.
Our test results showed that the design behind cable termination accessories can have an impact on electrical stress management and can help prevent premature electrical aging, failures, and power outages.
There are three crucial benefits of choosing 3M™ Cold Shrink QT-III Termination:
- Reliability:Â The Hi-K stress control helps to prevent leakage and electrical discharge for higher cable reliability.*
- Uniformity:Â The design allows for a uniform distribution of the electric field, helping lower surface stress and improve track resistance (i.e. friction).*
- Safety:Â 3M™ Cold Shrink QT-III Termination is easy to install and requires no additional jointing tools, it helps improve overall safety by helping lower the risk of cable preparation mistakes associated with longer insulation interfaces.*
Overall, test results showed that 3M™ Cold Shrink Termination technology has a excellent behaviour compared to the competitive stress cone technology.*
Further Reading
- Cable Terminations | Cold Shrink Terminations MV HV Cables
- 3M Cold Shrink Terminations Connecting Nexans 12kV (MV) Cable Onto Busbar
- 66kV Terminations | NEW Stock Introduction for 3M Cold Shrink Cable Terminations
- 3M Terminations | Surface Tracking on Medium Voltage Cable Terminations by 3M
Thorne & Derrick
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