MATERIALS
The size and type of cable shall be as shown on the Drawings. Unless otherwise specified cables shall have a voltage rating of 600/1000 volt complying with BS 6004. The number of cores in each cable shall be as shown on the Drawings. Where one earth continuity conductor (ECC) or neutral screen (NS) is shown, these shall be in addition to the number of cores indicated. Signal and communication cables may be shown as the number of twisted cable pairs.
Provide all cables shown on the Drawings and Schedules, and all lugs, links, terminals, glands, clamps, clips, saddles and ties necessary to complete the installation of the cables. Where cables are to be jointed, provide all junction boxes and in-line jointing kits.
TERMINOLOGY
Al – Aluminium conductor.
Cu – Copper conductor. Unless otherwise stated all conductors shall be plain annealed stranded copper.
MIMS – Mineral insulated, metal sheathed.
MIMS/PVC – Mineral insulated, metal sheathed, PVC covered.
XLPE/PVC – Cross-linked polyethylene insulated, PVC sheathed, to AS 3198.
NYY – PVC insulated and sheathed.
NYM – PVC insulated and sheathed.
NYA – PVC insulated. ATA – Aluminium tape armoured.
AWA – Aluminium wire armoured.
STA – Steel tape armoured.
SWA – Steel wire armoured.
COAX – Coaxial cable.
FLEX – Flexible cord or cable.
INSTRUMENT CABLES
- Sensor, instrument control loop and indication cables shall be screened industrial grade instrument cable unless otherwise specified.
- Instrument cables shall be run separated from power cables by a minimum spacing of 1000 mm. Where possible instrument cables shall follow a separate route from, and shall not be run parallel to large power cables or motor cables.
- Cable screens shall be earthed at one end of the cable only. Where screened cable circuits include an intermediate junction point the screens of the respective cables shall be bonded between the two sides of the junction.
- Where instrument cables enter panels and equipment, sealing glands shall be provided which effectively seal and clamp the cable sheath.
- Conductor terminations shall be made using correctly sized crimp lugs or pins.
- Cores that form pairs in a cable shall be connected so that their correct pair relationship is maintained.
COMMUNICATION CABLES
- Communication cables shall be industrial grade screened twisted pair data cable unless otherwise specified.
- Cable characteristics shall be suitable for the transmission rate and format to be used. Advise the Engineer of the proposed cable type before proceeding with procurement.
- Communication cable shall be run separated from power cables by a minimum spacing of 300 mm. Where possible communication cables shall follow a separate route from, and shall not be run parallel to large power cables or motor cables.
- Communication cable terminations and connectors shall match connectors fitted to equipment and shall be arranged to suit that equipment. Terminations shall be made in accordance with any manufacturer’s recommendations and with the recommended presses and tools to suit the connector type.
- Where communication cables enter panels, sealing glands shall be provided which effectively seal and clamp the cable sheath.
FIRE RESISTANT CABLING
Fire resistant cabling shall be copper conductor and fire rated for 2 hour in accordance with the fire conditions defined in IEC 331.
Cabling shall be flame retardant, self extinguishing, low smoke, and Halogen free.
Cabling shall comply with the following standards:
- IEC 331 Fire Resistant Tests
- IEC 60332 Flame Retardance Tests.
- IEC 1034 Smoke Emission Tests.
- IEC 754-2 Halogen Content Test.
Fire resistant cabling shall be installed in accordance with the manufacturer’s recommendations.
Fire resistant cabling shall be fixed with stainless steel cable ties. All termination shall be by crimping.
Fire resistant cabling shall have a voltage rating exceeding .6/1KV and shall be suitable for a 50 Hz mains system.
The outer sheath of all fire rated cable shall be brown in colour.
Where the jointing of fire resistant cabling is approved by the Engineer cabling shall be jointed using proprietary fire rated junction boxes and cable glands or by in line joints. Jointing techniques and materials shall be in accordance with the manufacturer’s recommendations. The fire resistance of the jointed cable shall be not less than the fire resistance of an unjointed cable.
MINERAL INSULATED COPPER CLAD CABLING
Where MIMS (Mineral Insulated, Metal Sheathed) is used to achieve specified fire rating, cabling shall be installed in accordance with the manufacturer’s recommendations. MIMS cabling shall have a voltage rating exceeding .6/1KV and shall be suitable for a 50 Hz mains system.
MIMS resistant cabling shall be copper conductor and fire rated for 2 hour in accordance with the fire conditions defined in IEC 60702. MIMS cabling shall be served with a PVC outer sheath. Jointing of MIMS cabling is to be subject to specific prior review by the Engineer. Cabling shall be jointed using proprietary fire rated junction boxes and cable glands or by in line joints.
Jointing techniques and materials shall be in accordance with the manufacturer’s recommendations. The fire resistance of the jointed cable shall be not less than the fire resistance of a unjointed cable. “Speedseal” jointing shall not be used.
MIMS cabling shall comply with the requirements of AS 3187, Mineral insulated metal sheathed cables. Terminations shall comply with AS 3188, terminations and glands. MIMS cabling shall be tested in accordance with the manufacturer’s recommendations no sooner than 24 hours after installation but within one week prior to energization.
INSTALLATION
All cable installation shall be carried out in accordance with the manufacturer’s written recommendations.
Cables shall be installed using the supporting systems shown on the Drawings. Refer Specification Section CABLE SUPPORT SYSTEMS for details and installation of supporting systems.
Installation shall be carried out so as to minimise failure under normal use, wear and tear, and any abnormal conditions which may reasonably be anticipated including electrical fault
conditions.
Single core cables forming part of a three phase system shall be rigidly held in trefoil formation by approved cable clamps. Such cable installations shall be capable of resisting the forces
arising from the prospective short circuit current. When parallel conductors are required, these shall be of equal length and shall follow substantially identical routes. Trefoil groups of parallel conductors shall each comprise one conductor of each phase.
Cable entries to equipment shall be made through glands, sleeves, or bushes in accordance with Specification Section CABLE TERMINATIONS.
Cabling to generator, motor or mechanical plant shall provide for vibration and movement by allowing cable slack or loops. Where necessary to allow for relative movement or extreme
vibrations, the fixed cabling shall terminate in a junction box and the final connections be completed with a flexible cable.
Care shall be taken during installation of cables to prevent cuts or abrasion damage to cable sheaths. Dry lubricant shall be applied to cables during pulling in of PVC sheathed or covered
cables to prevent welding or scuffing of cable sheaths. No cable shall at any time be bent to less than its minimum recommended bending radius. Cables shall not be installed where they
may be subject to damage due to a subsequent work (such as nailing of linings and the like). Cables shall not be embedded directly in concrete or plaster.
Where cables are liable to environmental damage, they shall be protected in a suitable manner. Where building features make it necessary to run cable through block walls or concrete slabs and the like, any such cable shall be protected within PVC conduit. All cables shall be protected where they pass through any openings, gaps, holes etc., by ensuring that surrounding surfaces are smooth and free of sharp edges etc., and that holes are bushed where necessary with close fitting plastic bushes. All cable entries to buildings and to equipment in exterior locations shall be vermin-proof and shall be firmly sealed to prevent ingress of gases and water. Where cables pass through fire rated walls or floors a fire barrier or fire rated sealing compound shall be used to seal the space after installation of the cables.
Cable lengths purchased shall be such that any cable runs required can be made without joints. Cables shall not be jointed except with specific prior review by the Engineer. Where joints are permitted they shall be accessible and in proprietary junction boxes or made with proprietary jointing kits to the approval of the Engineer.
Cables shall be adequately supported at all points and shall be neatly fixed with clips, saddles, cleats or ties as appropriate, and in accordance with the manufacturer’s written recommendations.
Cables shall be neatly arranged on trays or in trunking as shown on the Drawings. Twisting, unnecessary crossovers, bunching, excessive slack or excessive tightness shall be avoided.
Where cables join or leave trays, unnecessary crossovers and tangling of cables shall be avoided.
Subcircuit wiring shall be concealed. Where this is not possible, the cable route shall be subject to specific prior review by the Engineer. Where cables are supported on catenary wires, not more than eight cables shall be bunched together on any one catenary wire. Cables shall be securely clipped or tied to catenary wires using proprietary clips or ties.
Vertical cable rises exceeding 6 metres shall have loops or offsets to avoid differential movement between cable cores and sheath. Provision shall be made for longitudinal expansion occurring in long lengths of MIMS cables.
Cables which penetrate fire-rated walls and floors shall be treated in the following or equivalent manner: Paint the surface of each cable for a distance of 300mm from each side of the penetration with PYROSAFE KB-1 intumescent paint. Seal the penetration with PYROSAFE SVT universal bulkhead system, packing any gaps with FYRFYBA ceramic fibre. Small penetrations may be sealed with Fire Research foaming sealant.