260519_LV_Cables_TechSpecs_JULY_2012.pdf

26 05 19: TECHNICAL SPECIFICATIONS: LOW VOLTAGE CABLES

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JULY 2012 (100% FINAL)

Low Voltage Cables

Technical Specs

This document contains proprietary information and is protected by Copyright laws and should hence not be copied or published, in part or in whole, in any form or manner without the written approval of the Integrated Bureau for Engineering & Consultations (IBEC). The document shall be used for viewing and

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General

1- Work includes providing all wires, cables and connections, complete with all accessories in accordance with Drawings and Specifications and as required for a complete system. Wiring size referenced in this specification is metric.

2- Approved manufacturers are firms regularly engaged in the manufacture of wires, cables, and connections of types, sizes and ratings required and whose products have been in satisfactory use in similar service for not less than 5 years.

3- All supplied cables and wires shall comply with the following standards:

a. Applicable local codes.

b. IEC pertaining to wires, cables and connections.

c. DIN/VDE.

d. IEE Wiring Regulations.

In case of conflict among the referenced standards and codes, the more stringent provision will govern.

4- For the brand of cables and wires that will be supplied, the following will be submitted:

a. Manufacturers' data and catalogs on wires, cables and connectors

b. 25 cm sample cable of each type and size of wires and cables. Manufacturer Name, insulation class and reference data should be indicated on the samples.

Main and Sub-Main Cables

5- Contractor shall provide all of the mains cables shown on the drawings or detailed in the Electrical BOQ

6- All single and multi-core cables shall comply with IEC 502 and all conductors shall be copper conductors XLPE/PVC or PVC/PVC insulated/sheathed and shall have insulation class level not less than (0.6/1KV).

7- Copper conductors shall be stranded for sections 3mm2 and above.

8- Conductor sizes shall be metric, as shown on the Drawings. Conductors with cross-sectional areas smaller than specified will not be accepted.

9- The current carrying capacity of conductors has been determined in correlation with the specified type of insulation and the expected conditions of installation. No change will be accepted in the specified type of insulation, unless warranted by special conditions and approved by the Owner’s Consultant.

10- The insulation of each conductor shall be color coded or otherwise identified as required by the Regulations. Color coding or other marking shall be maintained throughout the entire installation.

11- For each batch of cables supplied a certificate of origin issued by the manufacturer stating its origin, manufacturer, constitution and standards to which it complies with will be provided. In the absence of such documents, the owner/consultant reserve the right to require that tests, at the contractor's expense, be performed by an official laboratory on samples taken from batches of cables delivered to the site. The contractor shall be responsible for any delays in the work resulting from non-compliance with the requirements mentioned above.

12- Cable installations whether so indicated or not shall include all joints and accessories at terminating ends or at tap-off points, earthing and bonding etc. carried out to completion.

13- Joints in cable shall not be accepted. Cables shall be supplied in lengths sufficient for a straight-through pull from termination to termination.

This document contains proprietary information and is protected by Copyright laws and should hence not be copied or published, in part or in whole, in any form or manner without the written approval of the Integrated Bureau for Engineering & Consultations (IBEC). The document shall be used for viewing and

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14- The definition of "Low Voltage" given in the IEE Wiring Regulations shall apply.

15- All cables shall be delivered to site with the manufacturer's seals, labels, or other proof of origin intact.

Such labels and seals shall not be removed until the cable is required for use, and shall be retained for inspection.

16- Unless otherwise specified herein or indicated on the drawings or in the Electrical BOQ, all cable over sheaths shall be black.

17- Cables shall be handled, terminated and installed in accordance with the cable manufacturer's recommendations. The technical advice of the manufacturer's specialists shall be followed if any special conditions or unusual circumstances apply.

18- Where cable sizes are not indicated on the drawings or in the Electrical BOQ, the contractor shall be responsible for determining the correct size of each cable. Cable sizes shall be determined on the basis of current rating and/or voltage drop and/or earth loop impedance, together within allowance for grouping with other cables and the method of installation, whichever is relevant, after taking into account the type of cable, the ambient conditions, the method of installation and the disposition of each cable relative to other cables.

19- Full details, with illustrations, of all cable supports and fixing devices shall be submitted before any orders are placed or work put in hand. All cable supports and fixing devices shall be designed to have a factor of safety of not less than 4.

20- Wherever cables pass through walls, ceilings, partitions and the like, a heavy-gauge PVC sleeve shall be provided, of internal diameter greater by at least 12 mm, but not more than 25 mm, than the diameter of the cable. The length of any such sleeve shall be such that each end projects by 5 mm beyond the surface of the element through which it passes, and the ends of they bore shall be provided with an adequate radius to prevent chafing of the cable sheath.

21- Wherever cables pass through floors a heavy-gauge steel sleeve shall be provided, of internal diameter greater by at least 12 mm, but not more than 25 mm, than the diameter of the cable and projecting above floor level by at least 50 mm.

22- Where cables pass through walls and/or floors which form part of the building's fire compartmentation, the hole(s) through which the cables pass shall be sealed after the cables have been installed, so as to give the same standard of fire resistance as the original wall or floor. Details of the proposed sealing method shall be submitted for approval prior to implementation.

23- All cables shall be separated from water, gas, and other piped services by a distance of not less than 150 mm unless the circumstances of the installation make this impossible. Fire resistant cables will be used where indicated on the drawings and they shall be made of copper conductors, XLPE/Steel wire armored type fire rated for 3 hours (950 °C), category C,W and Z with normal operating temperature (90 °C) to meet

BS 6387.

Installation

24- Cabling and wiring installation shall be performed strictly in compliance with the IEE Wiring Regulations

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25- Indoor distribution feeders and sub-feeders such as to distribution panel boards, motor control-gear, isolating switches etc. shall be in the form of single conductor pulled inside conduits, or raceways or multi-conductor cables clipped on cable trays, all as generally shown on the drawings. Where two or more cables are run in parallel, they shall be fixed on galvanized steel trays or in approved special cable supporting and protecting raceways.

26- Cables shall be fixed to the supporting structures with approved galvanized cast steel clamps at distances not exceeding 20 diameters.

27- No joints or splices shall be accepted on main feeders and sub- feeders.

28- Wires and cables shall be routed in such a way that they are not exposed to excessive heat or to corrosive agents. If such a condition cannot be complied with the wires and cables shall be of a type designed for the particular condition or enclosed in the necessary protective raceway, duct, concrete etc.

Installation of Sub-Circuit Wiring

29- All wires and cables shall be manufactured to comply with the relevant IEC Standard or equal standard.

The cables delivered to the Site shall bear the mark of identification of the manufacturer and the Standard to which it is manufactured. Any cable not having identification marks shall be rejected.

30- Final sub-circuit work originating from light and power panel boards shall be arranged as shown on the single line diagrams.

31- Final sub-circuit wiring shall be copper conductors, PVC/PVC and shall have insulation class level not less than (600/1000 V).

32- At least 150 mm of free conductor shall be left at each outlet, switch point and pull box for the making up of joints, or the connection of fixtures or devices, except where conductors are intended to loop without joints through lamp holders, receptacles and similar device boxes.

33- Generally, branch circuit conductor sizes are indicated on the drawings. Such sizes are minimum requirements and must be increased, where required, to suit the length of run and voltage drop, at no extra cost. Voltage drop from distribution transformers to furthest outlets shall be maximum 5%.

Terminations of LV Wires and Cables

34- Terminations of wires and cables of sizes up to 16 mm², shall be tightly twisted and where possible doubled back before being clamped. Where two or more wires are looped into the same terminal these conductors shall be tightly twisted together before being inserted into the terminals.

35- Wires and cables of sizes over 16 mm² shall terminate with sweated or compression type lugs. Insulating sleeve shall be used to protect any exposed part of the conductor or sleeve projecting beyond any insulated shrouding or mounting of a live terminal.

36- Glands for the various types of multi core cables shall be purpose made and suitable for the equipment enclosure.

Identification of Low Voltage Cables

37- Except in the case where it is terminated in full view onto a clearly labeled switch, starter, distribution board or similar piece of apparatus, or onto a motor or other equipment the function of which is evident, each and

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every cable end shall be provided with an approved means of identification. In particular, this requirement shall apply to all cables terminating on the back, or in the base, of cubicle type or similar switchboard or control panel and in any other case where the function of the cable is not immediately obvious.

38- The means of identification shall be as follows:

a. An engraved brass or aluminum label securely fixed to the cable sealing box.

b. An engraved brass or aluminum label securely tied to the cable with galvanized iron or tinned copper binding wire.

c. Self-adhesive embossed plastic labels will not be accepted as permanent means of identification.

39- The means of identification shall give the cable size, number of cores, and function together with the cable reference number if one has been allocated.

40- The cores of all control cables shall be individually identified, at terminations, by means of approved plastic ferrules bearing indelible characters, in accordance with the numbering on the relevant wiring diagrams.

41- All cables run above and under ground shall be identified by means of engraved brass or aluminum label at intervals not exceeding 30 meters. The labels shall bear details of the cable size, number of cores, function, and reference number (if any) and shall be securely attached to the cables with galvanized iron or tinned copper binding wires.

Inspection and Testing (Low Voltage Cables 600V) The tests to be carried out shall include but not necessarily be limited to:-

42- Visual and Mechanical Inspection

a. Inspect exposed sections of cables for physical damage and evidence of overheating.

b. Inspect bolted electrical connections for high resistance using one of the following methods:

i. Use of low-resistance ohmmeter.

ii. Verify tightness of accessible bolted electrical connections by calibrated torque-wrench method.

iii. Perform thermographic survey.

c. Inspect compression-applied connectors for correct cable match and indentation.

43- Electrical Tests

a. Perform resistance measurements through bolted connections with low-resistance ohmmeter, if applicable.

b. Perform insulation-resistance test on each conductor with respect to ground and adjacent conductors. Applied potential shall be 500 volts dc for 300 volt rated cable and 1000 volts dc for 600 volt rated cable. Test duration shall be one minute.

44- Test Values

a. Compare bolted connection resistances to values of similar connections.

b. Bolt-torque levels.

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c. Micro-ohm or milli-volt drop values shall not exceed the high levels of the normal range as indicated in the manufacturer's published data. If manufacturer's data is not available, investigate any values which deviate from similar connections by more than 50 percent of the lowest value.

d. Minimum insulation-resistance values should be comparable to previously obtained results but not less than two mega-ohms.

Small Wiring For the purpose of this specification, the description "small wiring" shall apply to all low voltage cables and wiring connected directly or indirectly to the public electricity supply system, or to any independent private supply system for the purpose of supplying electricity to general power and lighting circuits, but not including telephone, public address, and other communication circuits, fire detection, alarm, and other security circuits, cables and wiring forming part of a system for the control and/or supervision of the building Owner’s Consultanting services.

45- All cables to be used for small wiring shall comply with the relevant British Standards. The contractor shall submit with his tender package details of any internationally recognized Standards and Codes of practice he proposes to use au lieu of, or in addition to, those stated.

46- All wiring shall be carried out using one or more of the following wring systems, as indicated on the drawings:

a. Single-core unsheathed cables drawn into metallic or non-metallic conduit and/or trunking as specified elsewhere.

b. Twin- and/or multi-core sheathed cables, armored or unarmored, clipped to cable tray as specified elsewhere.

c. Flexible cords and/or cables.

47- All cables to be used for small wiring shall comply with the relevant DIN/VDE and IEC Standards.

48- PVC cables and rubber cables to according to IEC/DIN/VDE shall not under any circumstances be run underground.

49- No cables shall be installed unless the ambient temperature and the temperature of the cable are above 0oC, and have been so for the preceding 24 hours.

50- Where cables have subjected to temperatures below 0oC, care shall be taken to ensure that they are above that temperature for 24 hours before installation.

Acceptable Manufacturers Pirelli El Sewedy (Egypt)

BICC

Energya (Egypt) Or Approved Equal

Field Quality Inspection and Verification

51- Check for physical damage and proper connection in accordance with drawings.

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52- Megger conductors phase-to-phase and phase-to-ground for continuity and insulation testing before connection to utilization devices according to the following:

a. 100 percent of feeders.

b. 10 percent of branch circuits.

Perform tests prior to connecting equipment and in presence of authorized owner/consultant representatives.

53- Prior to energization, test wires and cables for electrical continuity and for short circuits.

54- Subsequent to wire and cable hook-ups, energize circuits and demonstrate functioning in accordance with requirements. Where necessary, correct malfunctioning units, and then retest to demonstrate compliance.

Replace units which cannot be satisfactorily corrected.

End of Specification