Underground Transmission Cable Laying Preparation in Korea: 6 Stages

Underground transmission cable laying preparation in Korea covers everything done before cables go into ducts and tunnels: material inspection, safety, cable work preparation, tunnel preparation, duct continuity tests and, for HVDC projects, submarine cable route surveys. Whether pulling day succeeds is largely decided by section-by-section tension calculations, the cable transport plan and route surveys. This guide covers all six stages.

Contents

• Common Pre-Work Review
• 1. Material Inspection
• 2. Pulling Work Safety
• 3. Cable Work Preparation
• Pre-Pulling Checklist
• 4. Cable Tunnel Preparation
• 5. Duct Continuity Test
• 6. HVDC Submarine Cable Route Survey
• FAQ
• Reference Standards
• Summary

Common Pre-Work Review

Before work, review the design documents, method statement, road occupancy permit and KEPCO standards, and study the pulling concept drawings for ducts, tunnels and direct burial. Prepare pulling equipment — pulling eyes, jacks, chain blocks, winches, caterpillar pullers, rollers, cable drums, tension meters, take-up winders, wire rope, cranes, cable guides (rollers, guide pipes, flexible tubes) and communications — and duct-test equipment such as wire rope, swivels, wire brushes and test mandrels. Measuring equipment includes a gas detector, earth resistance tester, insulation tester, multimeter and discharge device. On roads, set out notice boards, traffic signs (beacons, work-in-progress and slow signs), danger signs, safety fencing and cones with reflective tape for night visibility.

1. Material Inspection

1. Understand the regulations and design documents and secure test equipment so the materials selected suit the transmission project.
2. Prepare a list of required materials from the construction plan and secure materials and equipment.
3. On receipt, unpack and check quantities and damage against the packing list.

2. Pulling Work Safety

1. Wear safety equipment.
2. Install fall-prevention facilities according to the safety plan.
3. Secure the working area for pulling and fence it off from traffic and the public.
4. Install traffic and guidance signs and assign flaggers.

3. Cable Work Preparation

1. Calculate the pulling tension for each section from the design documents.
2. Estimate plant and labor for each section.
3. Train workers on how to operate each type of equipment before pulling.
4. For ducts, measure each section’s length with a draw wire.
5. Prepare a cable transport plan so cables arrive on site when needed.
6. Unpack cables and check for visible defects.

Before transport, walk the delivery route to check the height of overpasses, footbridges and tunnels and confirm the cable can pass, then transport safely in line with road regulations.

Pre-Pulling Checklist

Item	What to confirm
Tension	Pulling tension per section; tension limits set
Labor and plant	Plant and crew per section; equipment training
Ducts	Section lengths measured with draw wire; continuity and piece tests
Transport	Transport plan; height limits on route (overpasses, footbridges, tunnels)
Cable	Visual inspection after unpacking
Safety	Fencing, signs, flaggers, manhole gas measurement

4. Cable Tunnel Preparation

1. Prepare safety measures covering road occupancy permits and safety facilities.
2. Use a locator to confirm water, sewer, gas and telecom lines.
3. Drill for soldier H-piles.
4. Install lagging to secure working space and prevent collapse.
5. Excavate along the tunnel route as designed.
6. Install formwork for concreting and to prevent collapse.
7. Waterproof the tunnel and backfill.

5. Duct Continuity Test

1. Open the manhole and measure oxygen and toxic gas levels before entry.
2. Bring in equipment and assemble the mandrel and tools as designed.
3. Remove sediment and debris, then carry out the continuity test for cable entry.
4. If the test fails, carry out a piece test.

6. HVDC Submarine Cable Route Survey

1. Use charts, design documents and topographic maps to confirm landing-point conditions and the connecting grid.
2. Map the seabed with bathymetry, imaging, sub-bottom profiling and coring, and review route options.
3. Fix exact positions at sea and on land with control surveys.
4. Survey seabed relief, soil, currents and soil distribution with current meters and acoustic instruments.
5. Locate existing cables, bottom-trawling activity, artificial reefs and other obstacles with magnetometers, divers and sonar.
6. Review land reclamation, dredging and marine development plans near the route.
7. Review armor construction, characteristics and operating conditions for the submarine cable.
8. Decide cable type and length based on the selected armor.

Landing means bringing a submerged item such as a submarine cable ashore. Route selection decides the success of submarine cable projects, so clearances to existing cables and telecom lines, fishing activity and future reclamation or dredging must all be reviewed.

FAQ

Reference Standards

• Electricity Business Act (전기사업법) — law.go.kr
• Electrical Safety Management Act (전기안전관리법) — law.go.kr
• Electric Technology Management Act (전력기술관리법) — law.go.kr
• Electrical Construction Business Act (전기공사업법) — law.go.kr
• Occupational Safety and Health Act (산업안전보건법) — law.go.kr
• Korea Electro-technical Code (KEC, 한국전기설비규정) — law.go.kr
• KEPCO design standards; field practice manuals for transmission and distribution work; Korean Industrial Standards (KS)
• NCS competency unit Underground Transmission Cable Laying Preparation (지중송전케이블 깔기공사준비, 1901070233_22v4; NCS is Korea’s National Competency Standards) — ncs.go.kr

Summary

The most common mistakes in laying preparation are not checking height limits on the delivery route, so cables cannot reach site, and setting a pulling date without section-by-section tension calculations. Completing inspection, safety, tension and crew planning, duct measurement and testing, and marine route surveys is what keeps Underground Transmission Cable Laying on schedule. For pre-construction preparation, see Transmission Line Construction Planning. A Korean version of this guide is available here.

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This article restructures the Korean NCS competency unit ‘Underground Transmission Cable Laying Preparation’ (지중송전케이블 깔기공사준비, code 1901070233_22v4) as a practical reference. Actual work must follow applicable standards and the judgment of qualified professionals; always confirm specific values, deadlines and criteria against the latest regulations and client standards.

Written/reviewed by VOLT · Last updated 2026-10-25