Detailed Construction Plan for Heat-Shrinkable Cable Terminations

I. General Provisions
1. Project Overview:
   - The office building of the Design Institute R&D Base is a public structure with a frame-shear wall system. Most of the electrical cables in the installation project use cross-linked cables. During construction, heat-shrinkable cable termination technology was employed, with over 215 terminations made for cables ranging from 16mm² to 185mm², significantly improving project quality.

2. Scope of Application:
   - This technical standard applies to the construction of heat-shrinkable terminations for 1 (10) kV cross-linked polyethylene insulated power cables in general industrial and civil building electrical installation projects.

II. Construction Preparation
2.1 Equipment and Material Requirements
   - 2.1.1 All equipment and materials must comply with voltage levels and design requirements, and come with product certification.
   - 2.1.2 Main Materials: Insulated trifurcating gloves, insulating tubes, stress tubes, braided copper wire, filler glue, sealing tape, sealing tubes, phase-color tubes, rain skirts. Auxiliary Materials: Terminal lugs, solder, cleaning agent, sandpaper, white cloth, gasoline, soldering flux.

2.2 Main Tools:
   - Blowtorch, crimping pliers, steel tape measure, hacksaw, soldering iron, electrician's knife, wire cutters, screwdrivers, large porcelain tray.

2.3 Working Conditions:
   - 2.3.1 A spacious working area is required, with a clean construction site and access to 220V AC power.
   - 2.3.2 The ambient temperature should be above 0°C, with relative humidity below 70%. Construction is prohibited during rain, fog, or windy conditions.
   - 2.3.3 For overhead work (on poles), a platform should be set up, and a tent should be erected above the construction area to prevent dust intrusion (for outdoor work).
   - 2.3.4 Transformers, high-voltage switchgear (high-voltage switches), and cables should be installed, with cable insulation tested and qualified.

III. Construction Process
If the manufacturer provides a construction process, follow the manufacturer's instructions. Otherwise, proceed with the following steps. Ensure that the process from stripping to completion is continuous and completed in one go to avoid moisture ingress.

3.1 Process Flow:
   - Insulation testing → Equipment and material inspection → Stripping cable sheathing → Soldering ground wire → Wrapping filler and fixing trifurcating gloves → Stripping copper shielding and semi-conductive layers → Fixing stress tubes → Crimping terminals → Fixing phase-color sealing tubes → Power-on and acceptance testing → Fixing insulating tubes → Fixing rain skirts → Fixing sealing tubes → Fixing phase-color tubes → Power-on and acceptance testing.

3.2 Equipment and Material Inspection:
   - Unbox and inspect items to ensure they match the packing list and show no abnormalities. Arrange them in order on a large porcelain tray.

3.3 Cable Insulation Testing:
   - Open the cable ends and use a 2500V megger to test. Proceed to the next step only after passing the test.

3.4 Stripping Cable Sheathing:
   - 3.4.1 Outer Sheath: Secure the cable vertically with a clamp. Measure 750mm (550mm for indoor terminations) from the cable end and strip the outer sheath.
   - 3.4.2 Armor: Measure 30mm of armor from the outer sheath cut, bind it with wire, and strip the rest.
   - 3.4.3 Inner Layer: Measure 20mm of the inner layer from the armor cut and strip the rest. Remove the filler and separate the cores.

3.5 Soldering Ground Wire:
   - Use braided copper wire as the ground wire for the cable's steel tape and shielding. Split the braided wire into three strands, re-braid them around each phase, and solder them to the shielding copper tape using a soldering iron and solder. Sand the steel tape welding area, bind it with wire, and weld it to the steel armor. Fill the braided wire at the sealing point with solder to create a moisture-proof section.

3.6 Wrapping Filler and Fixing Trifurcating Gloves:
   - 3.6.1 Wrapping Filler: Use cable filler glue to fill and wrap the trifurcating area, shaping it into an olive-like form. Clean the cable sheath and core surfaces before wrapping with sealing tape. The maximum diameter of the wrapped sealing tape should exceed the cable outer diameter by about 15mm, enclosing the ground wire.
   - 3.6.2 Fixing Trifurcating Gloves: Slide the gloves onto the trifurcating base. Use a blowtorch to heat and shrink them into place, starting from the base and moving towards the ends.
   - 3.6.3 Precautions for Heating Shrinkable Materials:
     - 3.6.3.1 The heating temperature should be 110–120°C.
     - 3.6.3.2 Adjust the blowtorch flame to a soft yellow flame, avoiding high-temperature blue flames to prevent burning the heat-shrinkable material.
     - 3.6.3.3 When starting to heat the material, approach it slowly, moving the flame around to heat it evenly, and keep the flame in the direction of shrinkage to preheat the material.
     - 3.6.3.4 The flame should advance in a spiral pattern to ensure the tube shrinks uniformly around its circumference.

3.7 Stripping Copper Shielding and Semi-Conductive Layers:
   - Measure 55mm of the copper shielding from the glove fingertip and strip the rest. Measure 20mm of the semi-conductive layer from the copper shielding end and strip the rest.

3.8 Creating Stress Cones:
   - Clean the cable cores with alcohol and follow the requirements in Figure 2-26.

3.9 Fixing Stress Tubes:
   - Clean the copper shielding, semi-conductive layer, and insulation surfaces with a cleaning agent to ensure no carbon traces remain. Slide stress tubes onto each phase, overlapping the copper shielding by 20mm, and heat-shrink them from the bottom upwards.

3.10 Crimping Terminals:
   - Determine the lead length, adding 5mm to the terminal hole depth. Strip the core insulation and shape the end into a "pencil tip." Crimp the terminal, clean the surface, fill the gap between the terminal and insulation with filler glue, and overlap the insulation and terminal by 10mm to ensure smoothness.

3.11 Fixing Insulating Tubes:
   - Clean the insulating tube, stress tube, and glove surfaces, then slide the insulating tube to the trifurcating base (extending 10mm beyond the filler glue). Heat and fix it starting from the base.

3.12 Fixing Phase-Color Sealing Tubes:
   - Slide the phase-color sealing tube onto the terminal connection area, preheat the terminal, and heat-shrink it from the top. Indoor cable termination is now complete.

3.13 Fixing Rain Skirts:
   - 3.13.1 Fixing Three-Hole Rain Skirts: Slide the three-hole rain skirt into place according to the diagram and heat-shrink the neck to fix it.
   - 3.13.2 Fixing Single-Hole Rain Skirts: Slide the single-hole rain skirt into place according to the diagram and heat-shrink the neck to fix it.

3.14 Fixing Sealing Tubes:
   - Slide the sealing tube onto the terminal connection area, preheat the terminal, and heat-shrink it from the top.

3.15 Fixing Phase-Color Tubes:
   - Slide the phase-color tubes onto the sealing tubes and heat-shrink them into place. Outdoor cable termination is now complete.

3.16 Power-On and Acceptance Testing:
   - 3.16.1 Testing: After completing the cable termination, have the testing department conduct the required tests.
   - 3.16.2 Acceptance: After passing the tests, power on and run the system without load for 24 hours. If no abnormalities are found, complete the acceptance process and hand it over to the construction unit. Submit technical documents such as change orders, product manuals, certificates, test reports, and operation records.

IV. Quality Standards
4.1 Key Requirements:
   - 4.1.1 Cable terminations must be tightly sealed, with full filler and no bubbles or cracks. Core connections must be tight. The results of withstand voltage tests, leakage current, and insulation resistance must comply with construction standards.
   - 4.1.2 The semiconductor tape and shielding tape must not extend beyond the midpoint of the stress cone. The cone must be uniform and smooth.
   - 4.1.3 Cable terminations must be securely installed and fixed, with correct phase sequence.
   - Inspection Method: Visual inspection and review of installation and test records.

4.2 Basic Requirements:
   - Cable terminations should be aesthetically pleasing, smooth, wrinkle-free, and glossy.
   - Inspection Method: Visual inspection.

V. Product Protection
5.1 After inventorying equipment and materials, arrange them in order on a porcelain tray and cover them with white cloth to prevent debris from entering.
5.2 After completing the cable termination, notify the testing department to conduct tests as soon as possible. Once the tests are passed, install and fix the termination. Connect it to the transformer and high-voltage switchgear, and power it on. If power cannot be supplied immediately or other work is required, protect the cable termination to prevent damage.

VI. Quality Issues to Note
From stripping to completion, the process must be continuous and completed in one go to avoid moisture ingress.