Industrial plants such as refinery or petrol deposit, steel plants or any manufacturing units, having a Distributed Control System (DCS) where controlling and supervising is distributed among various subsystems throughout the plant, requires instrumentation cabling. Instrumentation cables are used to connect and convey low electrical signals used for controlling electrical power systems and subsystems.
Procedures of instrument cabling works include:
- Before beginning with cable laying/pulling, a thorough inspection has to be conducted on the cable trench, duct bank, raceway, cable tray etc. to ensure the routing was completed and free from foreign objects. Precise amount of sweet sand bed has to be laid before installation.
- Make sure that all documentation and paper works are completed before cable installation.
- All wires and cables have to be transported from the warehouse and laid down on the working area to avoid delay once the work is started.
- Check materials for any possible damages before transporting to the work area, if found as defective segregate them from the perfect ones.
- Take all safety precautions at the designated work sites.
- Double check the installation drawings prior to the construction.
- Check if cable materials and backups match the actual requirements needed to finish the installation.
- Test the performance of cable drums, verify maximum cable pulling tension etc.
Cable Installation Activities
- Position the cable rollers on the cable tray and the trench to which the cable will be installed. Safekeep these rollers all along the length with a spacing of at least 1.5 meters for an easy pull.
- After verifying the routing and destination, set up the cable reels to establish pulling points. Mark one end of the cable on the cable schedule using a permanent marker, then wrap it with clear tape. Do the exact same thing at the other end of the cable after cutting to denote the start and the end.
- Enough temporary scaffolds have to be installed to support cable rollers for easy movement of cables to the tray.
- Now pull the cable from the cable tray to its intended equipment.
- Drum location needs personnel to assist the turning of the drum while cable pulling is in progress.
- Instrument Supervisor must make sure that undue stress is not applied to the cable while pulling processes.
- Ensure minimum bending radius of cable, which shall not exceed cable manufacturer’s recommended values.
- Cables are identified at every splice and junction box.
- Pull the cables into the intended equipment by rope with basket grip and cut the cables. Now tape the cutting end with a rubber tape, then by a plastic tape to prevent moisture and dirt until time glanding and termination. Length of cable installed must be noted for future references.
- Fix the cable ties of control cables and protect them with fireproofed materials.
- Cover the power and control cables laid in the trench with sweet sand or any other selected filling materials whichever is preferred by the supervisors.
- Install cable identification tags for cables as per indicated in construction drawings and specifications.
- Unpaved areas are installed with post-type surface markers and paved areas are installed with permanent surface markers.
- Inspect and confirm the cable installation processes.
The best electrical construction companies in Saudi Arabia have the best equipment, talented workforce with electrical engineering skills and qualified engineers to supervise cable installations in trenches for an effective distributed control system in the plant.