PROCEDURE FOR INSTRUMENT CABLING WORKS
PROCEDURE FOR INSTRUMENT CABLING WORKS
- Pre-installation Activities
- Prior to cable laying/pulling, ensure that the cable trench, duct bank, raceway, cable tray and conduit installation was inspected and approved to ensure the routing was completed, clean and free from foreign objects and debris and sweet sand has been installed.
- Ensure that all relevant documents have been approved by Saudi Aramco prior to commencing cable installation, and that the latest revision of IFC drawings, specifications including approved procedures are disseminated to concerned personnel who will carry out the work.
- Ensure that all wires and cables to be transported from warehouse / lay down area to the working area comply with the project specifications.
- Check materials for damage before transporting to the work area. All materials of doubtful condition or quality shall be immediately segregated from the job site. An NCR must be raise, the materials shall not be use and sent to quarantine.
- Ensure that Insulation Resistance & Continuity test (on reel test) has been performed for all cable drums prior to cable pulling. Installed cables shall also be tested after cable laying.
- Secure work permit for cable pulling / installation and another associated works, if required.
- Ensure Safety Barriers are erected at designated work areas.
- Check and confirm actual proposed routing against approved construction drawings.
- For aboveground cable pulling, ensure adequate scaffold ladders and access ways are available at the work location.
- Check all the materials in the presence of QC with proper communication.
- Check cable schedule against actual requirements prior to cutting. Identify cable reel assignment.
- Verify the maximum cable pulling tension which cable can take before starting the cable pulling.
Cable Installation Activities
- Position the cable rollers on cable tray and trench to which the cable will be pulled / routed. Secure these rollers along the entire length of the cable tray /trenches with spacing of at least 1.5 meters for easy pull.
- After all routing and destination was cleared and verified, set up the cable reels in establish pulling points, mark one end of cable by writing the correct cable number base on the cable schedule using a permanent marker, then wrap it with clear tape. Do the same to the other end of the cable after cutting.
- Install adequate temporary scaffold to be used as support of cable rollers for easy movement of cable from the cable reel stand location up to the cable tray.
- Pull the cable in the cable tray / trenches to its intended equipment.
- Post personnel at the drum location to assist the turning of the drum when while pulling is in progress.
- Throughout the cable pulling process the Instrument Supervisor ensures that undue stress is not applied to the cable.
- Ensure the minimum bending radius of cable during pulling / routing as per project requirements.
- Bending radius shall not exceed cable manufacturer recommended values. Bend is free from deformities.
- Where cables of different voltage levels/service are run in parallel, segregation is in accordance with SAES-P-104, SAES-J-902 Section 14.1 through 14.2 or IFC Drawing.
- Cables are identified at each end at every splice and junction box.
- Pull cable and wires into the conduits or cable ducts by rope with basket grip with the application of pulling compound to prevent damage to cable insulation.
- After the cable are pulled to its intended equipment, ample allowance must be provided prior of cutting these cables. Tape the cutting end with a rubber tape then followed by plastic tape to prevent moisture and dirt until such time glanding and termination will be performed. Total length of each installed cable should be recorded.
- Power and control cables laid in tray shall be fixed with cable ties and protected with fire seal or fireproofed materials when entering Substation, PIB and AFD.
- Power and control cables laid in trench shall be filled with sweet sand / selected fill materials whichever is required.
- Install cable identification tags for cables pulled in trench, duct banks, cable trays and in conduits as specified in the construction drawings and specifications.
- Post type surface markers are installed for unpaved areas. Permanent surface markers are installed for paved areas.
- Following confirmation of cable pulling, submit “Request for Inspection” (RFI) to site QC Section, indicating scheduled time and date for inspection.
Cable Laying Methods
Laying by Hands:
- Laying by Hand – Cable rollers placed at distances of between 3 to 4m laying easier.
- Corner rollers or similar devices should be provided at any bend in the route, always maintaining the minimum bending radii of the cable. If the cable is not guided by rollers it must be guided by hand.
- The men supporting the cable should be spaced at between 4 to 6m along the cable.
Routing Requirements of Instrument and Control Cables and Data Highways
- Aboveground Routing – Armored Cable and Tray:
a) Cable tray supporting armored cables extending between field instruments and junction boxes shall be ventilated bottom, channel cable tray.
b) The armored cable shall be routed independently of existing overhead tray systems used for “home-run” cables. Commentary Note: This unsupported loop is required to provide sufficient slack for cable gland make-up and for easy removal of the cable from the device for future instrument change-out.
c) The unsupported end of the cable at the instrument shall be looped; this loop shall take into account the bending radius of the cable. The unsupported length of cable at the instrument shall be the minimum length required to provide the service loop.
d) The cable shall be either galvanized steel wire armor or galvanized steel interlocking armor, per 34-SAMSS-913.
2. Routing – Field Junction Box to Control Room Marshalling Cabinets: Cables between field junction boxes and marshalling cabinets may be routed in conduits, on trays or direct buried. The use of armored cables for homerun application is not recommended.
3. Control room cabling/wiring must conform to NEC Articles 725-61 and 725-82 (2005 edition). Wiring requirements for distributed control systems (DCS) are detailed in 23-SAMSS-010 (ARAMCO STANDARD).
- Routing requirements for above ground are in accordance with Section 13 and Paragraph 13.1 of SAES-J-902.
- Routing requirements for Underground are in accordance with Section 13 and Paragraph 13.2 & 188.8.131.52 of SAES-J-902 and SAES-P-104 Section 10.
- Routing requirements for cables under computer floors are in compliance with Section 13 Paragraph 13.3 of SAES-J-902.
- Cable and conduit entering building shall be in accordance with Section 5.2 and 5.4 of SAES-B-008 and Section 15.4 of SAES-P-104.
- Fire proofing cables in fire hazardous areas shall be in accordance with SAES-B-006 including electrical area classifications.
- The end(s) of ducts and conduit terminating below or in open air shall be sealed with duct sealing putty or an equivalent compound.Take enough duct seal compound and press in to gap of conduit opening.
- Smooth compound until satisfied with the result.
- Make sure area is clean and free from dust, dirt and other substances before application.
- Underground cable and underground conduit installation detailmade underground, using threaded PVC to rigid metal conduit adapters as per SAES-P-104, Para: 10.5
- PVC conduits shall not be extended above grade in industrial facilities. Where above grade extensions of buried PVC conduits are required, a transition shall be
- Cable fill and spare space availability in trays, conduit and duct banks. Commentary Note:
- Duct banks shall have 20% spare ducts (minimum one), unless this number is decreased by the facility Proponent as per SAES-P-104 Para. 10 Sec. 10.4.8.
- Because conductor sizes and insulation thickness of IEC and SASO type wires and cables vary from those of NEC type wires and cables, actual dimensions (outside diameters) must be used to calculate conduit fill and maximum number of wires allowed in conduit, instead of NEC tables.
- Conduit fill shall not exceed the maximum fill specified in Attachment 1, NEC Chapter 9, Table 1 & 4 and Notes to Tables.
- In new grass root projects, cable trays extending between the process area and the control room or process interface building, or trays installed beneath raised computer floors, in control rooms or PIB shall be sized for a minimum of 20% spare space for future expansions. This spare capacity is in addition to the installed 20% spare cabling as per SAES-J-902 Para. 9 Sec. 9.6
- Cable Tagging
- All cables shall be tagged, at each end, with a cable-tag
- Homerun cables shall be tagged with the assigned “IC” cable number.
- Cable tags outside junction boxes and marshalling cabinets shall be 316 SS with permanently marked alphanumeric characters i.e., raised or stamped characters.
- The cable tag shall be securely attached to the cable. All cable ties used in the field shall be “nylon 316 stainless steel” as per SAES-J-902 Para: 5.7.1
- All cable ties used inside of enclosures and buildings (i.e., field junction boxes, marshalling cabinets, control rooms, and PIBS) shall be weather resistant nylon cable ties with a stainless steel barb. The cable tie shall have a maximum continuous use temperature rating of 85ºC or higher as per SAES-J-902, Para: 5.7.2
TOOLS & EQUIPMENT FOR INSTRUMENT CABLING WORKS
- Cable reel stand
- Cable guide rollers
- Basket grips
- Stake-bed Truck
- Cable Cutter
- Man lift
- Cable Stripper
- Electrical Pliers
- Megger Tester
- Multi Tester
- Other Relevant Tools