Most premature medium-voltage cable failures do not start in the cable – they start at the ends. Terminations and joints are assembled in the field, by hand, in conditions that are often dusty, humid or hurried. Workmanship defects – incorrect stripping, contamination, wrong stress-control placement, moisture ingress – create the weak points that fail years early. Quality control of termination installation is therefore one of the highest-return activities in cable asset management.
Why terminations fail early
Field assembly risk
Unlike the factory-produced cable, a termination is built at the site: insulation stripped to length, stress control applied, connectors fitted, the whole assembly sealed. Each step carries workmanship risk.
Environmental exposure
Humidity, dust and rain during installation contaminate the insulation interface. Moisture in the termination migrates under voltage stress and drives discharge activity.
Quality control at installation
1. Procedure discipline
Follow the kit manufacturer’s installation instructions step by step: correct stripping dimensions, clean surfaces, correct stress-control placement, proper connector crimping and sealant application. Installer certification and procedure adherence are the first line of control.
2. Environmental management
Control dust and moisture during assembly – shade, cleanliness and dry conditions matter as much as the components themselves.
3. Electrical verification
Prove each termination electrically before service:
- PD testing (OWTS) – detects discharge activity at terminations and joints, localising defects to the exact position.
- Withstand testing – proves the termination survives the specified voltage stress.
- Visual and dimensional checks – documented per termination.
4. Documentation
Record every termination: kit type, installer, date, conditions, test results. A documented termination register makes responsibility clear and supports warranty claims.
Acceptance testing as the control point
Oscillating wave acceptance testing before energisation is the decisive control: it finds workmanship defects while the jointing crew is still on site. A termination that passes acceptance has a clean PD map recorded as its baseline – and that baseline is the reference for every future diagnosis of the circuit.
Building termination QC into projects
- Specify the acceptance PD limit and test procedure in the contract before work begins.
- Require installer certification for the termination kits used.
- Witness acceptance testing and keep the records in the asset register.
- Retest after major repairs or re-jointing.
About HUWOR
Zhuhai Huawang Technology Co., Ltd. (HUWOR) manufactures oscillating wave test sets and PD diagnosis systems used for cable termination acceptance testing, supporting utilities, EPC contractors and testing companies worldwide with OEM/ODM supply and application guidance. Contact the HUWOR sales team for specifications.