Substation cable installation in Korea covers installing cable trays and fittings and pulling and jointing power and control cables to wherever energy is needed inside the substation, following the design. A substation has hundreds of control cores running into its equipment, so poor separation and labeling cause confusion at testing and maintenance, while each power cable joint is a likely fault point. This guide covers four stages: cable trays, control cables, power cable pulling and power cable jointing.
Contents
- Common Pre-Work Review
- 1. Cable Trays
- 2. Control Cables
- 3. Power Cable Pulling
- 4. Power Cable Jointing
- Quality Points by Stage
- FAQ
- Reference Standards
- Summary
Common Pre-Work Review
Review the design documents (drawings, calculations, specifications, procurement and fabrication specs, cost breakdown), manufacturer drawings, schedule, the Technical Standards for Electrical Equipment, KEC and KS. The site construction manager confirms that staffing meets the engineer-assignment rules in the Electrical Construction Business Act for the project size. The safety plan covers training, the safety budget, PPE supply, emergency contacts, inspections by process, site surroundings and accident response. Prepare cable cutters, torque wrenches, a compression tool, multimeter and insulation tester; workers wear insulating gloves, hard hats, vests, safety glasses and dust masks.
1. Cable Trays
- Confirm trays and supports can carry their own weight plus the cables, and have no rough edges that could damage sheaths.
- Make wall and floor penetrations fully sound mechanically, electrically and for fire stopping.
- Use proper fittings for changes of direction and joins between trays of different widths.
- On ceilings and walls, use hangers and brackets that carry the full load.
- Keep proper support spacing and fix horizontal runs firmly to cross members.
2. Control Cables
- Install the cable and conductor sizes exactly as designed.
- Separate phases by color for electrical safety and maintenance.
- Read and understand the sequence between installed cables and equipment.
- Group cables by purpose, function and equipment according to the termination list.
3. Power Cable Pulling
- Set up cable drums and mark phases on the cable.
- Monitor tension during pulling so it stays within limits, preventing drum jacks from toppling and cables from tangling.
- After winching, cut and phase-mark the cable and seal ends with waterproof tape.
- Before energizing, carry out a withstand test witnessed by the supervisor.
4. Power Cable Jointing
- Joint according to the cable type and manufacturer’s method.
- Remove the outer sheath to cut back the metallic sheath.
- Make an offset to keep thermal expansion stress off the joint.
- Expose the conductor and pencil the insulation.
- Compress sleeves for each cable size with a compression tool.
- Reinforce insulation with paper build-up and housing work.
- Earth the joint for safety and apply corrosion protection to the metallic sheath.
- Run a withstand test before energizing.
Termination methods differ by manufacturer, so follow that manufacturer’s jointing instructions exactly.
Quality Points by Stage
| Stage | Key checks |
|---|---|
| Cable trays | Strength, smooth surfaces, fire-stopped penetrations, support spacing |
| Control cables | Size, phase and color separation, grouping and labeling per termination list |
| Power cable pulling | Phase marking, tension monitoring, waterproof ends |
| Power cable jointing | Offset, penciling, sleeve compression, insulation build-up, corrosion protection |
| Before energizing | Withstand test witnessed by the supervisor |
Support spacing, allowable pulling tension and test voltages follow KEC, client standards and cable manufacturer instructions.
FAQ
What matters when a tray passes through a wall?
The penetration must be sound mechanically and electrically and must also provide fire stopping.
Why offset a power cable at the joint?
Cables expand and contract with temperature. An offset gives slack and reduces thermal stress on the joint.
When is the withstand test done?
After pulling and jointing, before energizing, witnessed by the supervisor to confirm cable quality.
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
- Technical Standards for Electrical Equipment (전기설비기술기준) — law.go.kr
- KEPCO design standards and substation construction practice; Korean Industrial Standards (KS)
- NCS competency unit Substation Cable Installation (케이블 설치공사, 1901070315_22v2; NCS is Korea’s National Competency Standards) — ncs.go.kr
Summary
The most common mistakes are mixing control cables against the termination list and neglecting tension monitoring when pulling power cables. Trays depend on strength and fire-stopped penetrations; control cables on grouping and labeling; pulling on tension and sealed ends; and jointing on the manufacturer’s method and withstand testing. Related guides: Substation Structure Installation, Substation Switchboard Installation, Substation Auxiliary Power Installation. A Korean version of this guide is available here.
This article restructures the Korean NCS competency unit ‘Substation Cable Installation’ (케이블 설치공사, code 1901070315_22v2) 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 2026-10-26