EHV & MV Cable Jointing

Extra High Voltage (EHV) and Medium Voltage (MV) cable networks form the backbone of industrial, commercial, and utility power distribution systems. Proper jointing, termination, testing, and commissioning ensure safety, reliability, system efficiency, and long-term performance. Our expertise covers the complete lifecycle—from cable preparation to energization.

1. Cable Jointing (EHV & MV)

1.1 Cable Preparation

• Visual inspection of cable drums and route.
• Correct measurement and marking of jointing points.
• Removing insulation, semi-conductor layers, and armour using specialized tools.
• Ensuring cable ends are clean, smooth, and contamination-free.

1.2 Jointing Process

We follow OEM and IEC/IS standards for heat-shrink or cold-shrink joint kits. Key steps include:

• Straight joint installation with proper alignment.
• Stress control and insulation rebuilding.
• Application of joint sleeves, tubes, and sealing components.
• Use of torque-controlled crimping for connectors.
• Moisture protection to ensure long-term joint stability.

1.3 Termination (Indoor/Outdoor)

• Installation of indoor terminations using heat-shrink/cold-shrink kits.
• Outdoor terminations with sheds, anti-tracking materials, and weatherproofing.
• Earthing and bonding connections as per safety norms.
• Phase identification, lug crimping, and gland fitting.

1.4 Quality & Safety Measures

• Work done only by certified jointers.
• Dedicated safety protocols for handling EHV/MV systems.
• Use of calibrated tools and approved materials.

2. Cable Laying & Route Management

Although optional, cable jointing is usually part of the overall installation:

• Trenching, sand bedding, and backfilling.
• Cable tray, trench or duct installation.
• Cable pulling with rollers, jacks, and tension control.
• Laying of power, control, and earthing cables.
• Cable dressing, clamping, and identification tagging.

3. Electrical Testing (Before & After Jointing)

Testing ensures the reliability and safety of the cable system.

3.1 Pre-Installation Testing

• Continuity test
• Insulation resistance (IR) test
• Conductor resistance measurement

3.2 Post-Jointing Testing

Performed using advanced diagnostic equipment:

• VLF Testing (Very Low Frequency): Applies AC test voltage to check insulation strength and detect weaknesses.
• Tan Delta Testing: Measures insulation health and aging.
• Partial Discharge (PD) Testing: Identifies microscopic insulation defects.
• Hi-Pot (High Potential) Test: Verifies dielectric strength of cables.
• Sheath Integrity Testing: Checks for sheath faults and mechanical damage.

4. Commissioning Activities

Once testing is complete, commissioning ensures the system is ready for energization.

4.1 System Verification

• Phase sequence and polarity check.
• Verification of earthing and bonding connections.
• Checking control & protection circuits.
• Ensuring proper cable routing & clearance.

4.2 Documentation & Reports

• Test reports: IR, VLF, PD, Hi-pot, continuity.
• As-built drawings of cable routes and joints.
• Material certificates and quality checklists.
• Safety compliance and energization permit.

4.3 Energization Support

• Final inspection with client/consultant.
• Gradual energization of cables.
• Monitoring for abnormal heating, PD, or load imbalance.
• Technical support during initial load run.

5. Why Professional Jointing & Commissioning Matters

• Prevents breakdowns and costly maintenance.
• Ensures long-term stability under high load conditions.
• Reduces risk of faults, heating, and electrical hazards.
• Meets regulatory and utility standards.
• Guarantees system performance for 20–30+ years.

6. Applications We Serve

• Industrial plants
• Power utility substations
• Metro & railway projects
• Commercial buildings
• Smart city & infrastructure networks
• Renewable energy (solar/wind evacuation lines)
• Data centers & hospitals
• Airport & port facilities