ICS 29.060 NRS 061-1:2002

ISBN 0-626-13743-8 First edition

SPECIFICATION FOR OVERHEADGROUND WIRE WITH OPTICALFIBRE

Part 1: Product specification

Preferred requirements for applications inthe Electricity Supply Industry

N R S

Rationalized User Specification

This Rationalized User Specification isissued by the NRS Project

on behalf of theUser Group given in the foreword

and is not a standard as contemplated in the Standards Act, 1993 (Act 29 of 1993).

Rationalized user specifications allow userorganizations to define the performance and quality

requirements of relevant equipment.

Rationalized user specifications may, after a certainapplication period, be introduced as national standards.

Amendments issued since publicationAmdt No. Date Text affected

Correspondence to be directed to Printed copies obtainable from

South African Bureau of Standards South African Bureau of Standards(Electrotechnical Standards) Private Bag X191Private Bag X191 Pretoria 0001Pretoria 0001

Telephone: (012) 428-7911Fax: (012) 344-1568E-mail: sales@sabs.co.zaWebsite: http://www.sabs.co.za

COPYRIGHT RESERVED

Printed on behalf of the NRS Project in the Republic of South Africaby the South African Bureau of Standards1 Dr Lategan Road, Groenkloof, Pretoria

1 NRS 061-1:2002

Contents

Page

Foreword ................................................................................................................................ 3

Introduction ............................................................................................................................ 4

Key words .............................................................................................................................. 4

1 Scope .............................................................................................................................. 5

2 Normative references ...................................................................................................... 5

3 Terms, definitions and abbreviated terms ........................................................................ 6

4 Requirements .................................................................................................................. 7

4.1 General .................................................................................................................... 7

4.2 Construction ............................................................................................................. 7

4.3 Design information ................................................................................................... 11

4.4 Samples ................................................................................................................... 14

5 Tests ................................................................................................................................ 14

6 Marking, labelling, packaging and documentation ............................................................ 18

Annexes

A (informative) Guide to purchasers on preparing an enquiry ........................................................ 20

B (informative) Model form for schedules A and B ......................................................................... 22

Bibliography ........................................................................................................................................ 23

NRS 061-1:2002 2

Foreword

This specification was prepared on behalf of the Electricity Suppliers Liaison Committee (ESLC) andapproved by it for use by supply authorities. This specification is based on an Eskom, Transmissiondocument (TRMSCAAD6: 1998) compiled by Messrs M. Korber and D.C. Smith. This specification wasprepared by a Working Group comprising the following members:

G S Anderson Nelson Mandela Metropolitan MunicipalityM Gittings eThekwini Metropolitan CouncilA Gouveia Cape Town Electricity DistributorP O’ Halloran City Power Johannesburg (Pty) LtdF M Lukacsovics eThekwini Metropolitan CouncilV N Mokoena (Project Asst) NRS ProjectP H Pretorius Eskom (TSI)V Sewchand (Project Leader) NRS Project J Shillington City Power Johannesburg (Pty) LtdD C Smith (Chairman) Eskom TelecommunicationsI van der Merwe Eskom (Western Cape Region)

A Manufacturers Interest Group (MIG) was also consulted on the contents of this part of NRS 061 and itscomments were incorporated where the working group was in agreement. The MIG comprised thefollowing members:

A Dietchman ATC CablesP Muller Cable Manufacturers AssociationR Phillips Aberdare Cables

The Working Group was appointed by the ESLC, which, at the time of approval, comprised thefollowing members:

eThekwini Metropolitan Council, AMEUR Wienand (Chairman)M N Bailey Distribution Technology , EskomA J Claasen Electrotechnical Standards, SABSN Croucher City of Cape TownP Crowdy Distribution Technology, EskomW G H Dykman City of Tshwane, AMEUA H L Fortmann eKurhuleni, AMEUJ S van Heerden SABS NETFAP A Johnson Technology Standardization , EskomJ G Louw City of Cape Town (Tygerberg)D M Michie Nelson Mandela Metropolitan Municipality, AMEUA J van der Merwe Mangaung Electricity, AMEUP J S van Niekerk City Power Johannesburg (Pty) Ltd

Recommendations for corrections, additions or deletions should be addressed to the NRS ProjectManager, c/o SABS, Private Bag X191, Pretoria, 0001.

ISBN 0-626-13743-8

3 NRS 061-1:2002

Introduction

This specification was prepared to establish and promote uniform requirements for overhead groundwire with optical fibre. This specification is intended to enable purchasers to acquire the specifiedequipment without the need for detailed and extensive contract documents.

The ESLC expresses the wish that, in the national interest and in support of government policy tofoster local manufacture and stimulate export, all purchasers adopt the requirements of thisspecification insofar as their particular conditions will allow. Any differences between thisspecification and the corresponding purchasers requirements should, as far as possible, be clearlyindicated in the schedules attached to this specification and, where appropriate, be submitted forconsideration in future reviews of this specification.

Key words

Optical ground wire.

NRS 061-1:2002 4

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5 NRS 061-1:2002

SPECIFICATION

Overhead ground wire with optical fibre

Part 1: Product Specification

Preferred requirements for applications in the Electricity Supply Industry

1 Scope

This specification specifies the essential mechanical, electrical and optical characteristics,acceptance criteria and test requirements for metallic armoured optical ground wire (OPGW) forapplication with a nominal voltage from 66 kV up to and including 765 kV.

2 Normative references

The standards contain provisions that, through reference in the text, constitute requirements of thisspecification. At the time of publication, the editions indicated were valid. All standards are subjectto revision, and parties to agreements based on this specification are encouraged to investigate thepossibility of applying the most recent revisions of the standards listed below. Information oncurrently valid national and international standards may be obtained from the South African Bureauof Standards.

IEC 60793-1:1995, Optical fibres — Part 1: Generic specification (all sections).

IEC 60793-1-30:2001, Optical fibres — Part: 1-30: Measurement methods and test procedures —Fibre Proof test.

IEC 60793-1-47:2001, Optical fibres — Part: 1-47: Measurement methods and test procedures —Macrobending loss.

IEC 60793-2:2001, Optical fibres — Part 2: Product specifications.

IEC 60794-1-1:2001, Optical fibre cables — Part 1-1: Generic specification — General.

IEC 60794-1-2:1999, Optical fibre cables — Part 1-2: Generic specification — Basic optical cabletest procedures. (Method E3; Method E4; Method F5).

IEC 60794-4-1:1999, Optical fibre cables — Part 4-1: Aerial optical cables for high-voltage powerlines.

IEC 60815:1986, Guide for the selection of insulators in respect of polluted conditions

IEC 60889:1987, Hard-drawn aluminium wire for overhead line conductors.

IEC 61089:1991, Round wire concentric lay overhead electrical stranded conductors.

IEC 61232:1993, Aluminium-clad steel wires for electrical purposes.

IEC 61312-1:1995, Protection against lightning electromagnetic impulse — Part 1: Generalprinciples.

NRS 061-1:2002 6

IEC 61395:1998, Overhead electrical conductors — Creep test procedures for stranded conductors.

IEC/TR 61282-3 [B.1]:2000, Fibre optic communication system design “guides” —Part 3: Calculation of PMD in fibre optic systems. (In course of preparation. Publication due 2002)

IEC/TS 61941:2000, Optical Fibres — Polarization mode dispersion measurement techniques forsingle-mode optical fibres.

ITU-T Recommendation G.650:2000, Definition and test methods for the relevant parameters ofsingle-mode fibres.

TIA/EIA-598-A, "Optical Fibre Cable Colour Coding".

3 Terms, definitions and abbreviated terms

For the purposes of this specification, the following terms, definitions and abbreviations apply.

3.1 Terms and definitions

3.1.1 approved (approval): Approved in writing by the purchaser.

3.1.2 length: It is the complete length of cable drawn from a pre-form during manufacturing.

3.1.3 maximum allowable ovality: The maximum allowable ovality of a cable or of itscomponent, which is specified by the manufacturer.

3.1.4 optical ground wire: An earth wire conductor with optical fibres embedded within a steel oraluminium earth wire. It must be able to carry both lightning strikes and fault currents withoutdetrimental effect to the optical fibre telecommunication facilities.

3.1.5 ovality: It is a percentage ratio of diameters according to: (d1 – d2) / (d1 + d2) % where d1 isthe maximum measured diameter of the cable and d2 is the minimum diameter of the cablemeasured at the same cross-section as d1.

3.1.6 rated tensile strength: The calculated breaking load of the OPGW construction.

3.2 Abbreviated terms

3.2.1 MAO: Maximum allowable ovality.

3.2.2 OPGW: Optical ground wire.

3.2.3 OTDR: Optical time domain reflectometer.

3.2.4 PMD: Polarization mode dispersion.

3.2.5 ROC: Radius of curvature

3.2.6 RTS: Rated tensile strength.

7 NRS 061-1:2002

4 Requirements

4.1 General

4.1.1 The OPGW shall contain the optical fibres, and the necessary protective outer layer toprevent damage to the fibres due to mechanical elongation, bending, twisting, crushing forces aswell as the effects of elevated temperatures due to fault currents. The OPGW should bemechanically constructed in such a way so as to protect against environmental degrading factors.

4.1.2 The stranded bare conductor shall consist of one or more layers of metal wires, to providematerially the same electrical and mechanical characteristics as a conventional overhead groundwire.

4.1.3 Designs where any synthetic material containing the fibres is likely to be exposed topollutants in the atmosphere or ultra-violet radiation from the sun, for example, where bird-caging ofthe outer layer of the conductor occurs as in the case of a single layer configuration will not beaccepted, unless otherwise approved by the customer.

4.1.4 The OPGW shall comply with all the requirements of IEC 60794-4-1. The cable shall begreased as per IEC 61089 if necessary and shall be specified in schedule A.

4.1.5 Unless otherwise specified in schedule A, the OPGW shall be designed to operate withinspecification under the following operating conditions:

a) Pollution level (as per IEC 60815): heavy;

b) Maximum temperature: 50 °C;

c) Minimum temperature: -10 °C;

d) Maximum wind speed: 36 m/s; and

e) Route altitude: 2000 m.

4.1.6 The following information shall be stated in schedule B:

a) name of manufacturer;

b) place of manufacturer; and

c) manufacturer’s reference number.

4.2 Construction

4.2.1 Fibre optic

4.2.1.1 Optical fibres

These shall be single mode fibres in accordance with (ITU-T Recommendations G 650),IEC 60793-1 and IEC 60793-2.

NRS 061-1:2002 8

4.2.1.2 Fibre carrier

The fibre carrier shall house the optical fibres, and also protect them from damage caused by largetemperature variations as a result of overcurrent conditions, moisture ingress and mechanical forcessuch as crushing, bending, twisting, tensile stress, aeolian vibrations and mechanical forces. Thefibre carrier shall consist of a stainless steel or aluminium/aluminium alloy tube or channelled rod.Other designs may be considered. The type of fibre carrier shall be either G.652 or G.655, asspecified in schedule A.

4.2.2 Armour

4.2.2.1 The OPGW armour which is the conductor excluding the optical fibre carrier, shall bedesigned to provide similar mechanical and electrical characteristics as a conventional shield wire,and satisfy the short-circuit current requirement, as specified in schedule A.

4.2.2.2 The basic construction of the armour shall comprise bare metallic wires of unique orcombined metals stranded in one or more layer(s). The stranded wires shall be any of the followingmaterials:

a) galvanized steel;

b) aluminum alloy as per IEC 60889; or

c) aluminum clad steel as per IEC 61232.

The stranded wires shall be made of multiple layers, and can be of combined metal types in eachlayer. The stranding and wire diameter shall be specified in schedule B.

4.2.2.3 The direction of lay shall be reversed in successive layers.

4.2.2.4 The finished wires shall contain no joints or splices.

4.2.2.5 The wires shall be so stranded that, when the complete OPGW is cut, the individual layerscan easily be regrouped.

4.2.3 Attenuation and dispersion

When tested in accordance with 5.1.2.1, the PMD design value shall be as specified in table 1 andtable 2 for G.652 and G.655 fibres respectively, with a probability of 0,0001 that this value beexceeded for a numerical concatenation of 20 lengths of cables and measurement shall be done perIEC/TS 61941. The value of PMDsubQ shall be determined by the Monte Carlo method ofIEC/TR 61282-3 [B.1] such that when the fibre is cabled, PMDsubQ shall be equal to the valuespecified in tables 1 and 2 with m = 20 and Q = 0,01 %.

4.2.4 Proof stress

When tested in accordance with 5.1.2.2, during manufacture, or subsequent works testing, the entirelength of each fibre shall be subjected to a proof test of at least 1 % elongation with an unload timeof 20 m s.

9 NRS 061-1:2002

4.2.5 Macro-bend resistance

When tested in accordance with 5.1.2.3, the attenuation increase shall be less than the valuespecified in table 1 and table 2 for G.652 and G.655 fibres respectively. Where G.652 fibre isspecified, a 100 turns shall be placed on a 50 mm diameter mandrel. Where G.655 fibre is specified,a 100 turns shall be placed on a 75 mm diameter mandrel.

4.2.6 Crush resistance

During stringing, the conductor is subjected to side compression when it passes over metal pulleysor when clamps are installed. To endure these stresses, the OPGW shall have a high anti-crushingresistance. When tested in accordance with 5.1.3.2, there shall be no measurable permanentchanges in optical attenuation at 1550 nm, while any temporary change in attenuation shall be lessthan 0,1 dB.

4.2.7 Tensile performance

The OPGW shall be so designed that it can withstand a specified tensile load without deleteriousinfluence on the optical fibres. When tested in accordance with 5.1.3.3, the change in attenuationshall be less than 0,05 dB/km from no load to 50 % of the RTS of the cable.

4.2.8 Cable deformation

During installation the OPGW cable shall be subjected to passing, under tension, over several metalpulleys.

The cable shall be constructed so that when tested in accordance with 5.1.3.4, the ovality of theOPGW and its components shall remain under 10 % and there shall be no change in fibreattenuation at 1 550 nm before and after the test.

4.2.9 Stress-strain

When tested in accordance with 5.1.3.1, there shall be no visual change to the OPGW strands.

4.2.10 Impact

When tested in accordance with 5.1.3.5, there shall be no measurable permanent changes in opticalattenuation at 1 550 nm, while any temporary change in attenuation shall be less than 0,1 dB.

4.2.11 Aeolian vibration

The optical attenuation increase shall be less than 0,05 dB/km at 1550 nm and when tested inaccordance with 5.1.3.6, any significant damage to the components of the cable shall constitutefailure of the test.

4.2.12 Conductor creep

When tested in accordance with 5.1.3.7, the manufacturer shall submit records of a long term(>1 000 h) elongation test, with extrapolation to 15 years of an OPGW sample tensioned at 20 %RTS.

NRS 061-1:2002 10

4.2.13 Temperature cycle

When tested in accordance with 5.1.3.8, the changes in attenuation over the last four cycles shallnot exceed 0,10 dB/km from the mean. The mean attenuation shall be defined as the averageattenuation encountered at 20 °C over the last 4 cycles.

A temperature cycle shall be:

T1 T2 T3 T1

+20 °C -10 °C +70 °C 4 hours

a) T1 = + 20 °C

b) T2 = - 10 °C

c) T3 = + 70 °C, and

d) T1 = 4 hours

Figure 1 — Temperature cycle

4.2.14 Short - circuit current

When tested in accordance with 5.1.4.1, any temporary increase in attenuation shall be less than0,1 dB/km at 1 550 nm, while any permanent increase shall be considered a failure. Bird-caging orbreaking of the conductor strands shall also be considered as failure of the test.

T2

T1

T3

t1t1

Tem

pera

ture

Time

11 NRS 061-1:2002

4.2.15 Lightning

When tested in accordance with 5.1.4.2, no severed strands shall be visible and the remainingstrength of the OPGW sample shall be at least 90 % of the original RTS. There shall be nomeasurable permanent change in fibre attenuation at 1 550 nm. (see 4.3.1.6).

4.2.16 Routine test

When tested in accordance with 5.2, each fibre shall be measured for continuity and length, whilethe cable is on a drum, prior to delivery.

4.2.17 Sample test

When tested in accordance with 5.3, sample tests shall be performed to ensure that the materialused and the manufacturing processes are without defect.

4.3 Design information

4.3.1 Optical aspects

4.3.1.1 The required number of loose buffered single mode fibres to be incorporated in the cable willbe specified in schedule A. Each fibre shall be uniquely identified in an approved manner as perTIA/EIA-598-A.

4.3.1.2 The fibre carrier design shall be such that no moisture shall be able to penetrate and comein contact with the fibres.

4.3.1.3 The cladding of the fibres for both G.652 and G.655 fibres shall comply with ITU-Trecommendations G.652 or G.655 and are specified in table 1 and table 2 respectively. The claddingconfiguration, whether depressed or matched will be specified in schedule A. The G.652 fibres shallbe capable of operating in both the 1 310 nm and 1 550 nm wavelengths while the G.655 fibre shalloperate in the 1 550 nm region, depending on specific link requirements. The required attenuation,chromatic dispersion coefficient, PMD characteristics, mode field diameter and concentricity errorare also specified in tables 1 and 2.

NRS 061-1:2002 12

Table 1 — Specifications for G.652 fibre

1 2

Attributes Value

1. Cladding diameter 125 µm ± 1,0 µm

2. Cladding non-circularity ≤ 1,0 %

3. Attenuation coefficient at

a) 1 290 nm to 1 340 nm < 0,36 dB/km

b) 1 525 nm to 1 575 nm < 0,25 dB/km

4. Chromatic dispersion coefficient at

a) 1 310 nm < 3,5 ps/nm.km

b) 1 550 nm < 18 ps/nm.km

5. Polarization mode dispersion (PMD) ≤ 0,5 ps/√ km

6. Mode field diameter at

a) 1 310 nm 9,2 ± 0.4 µm

b) 1 550 nm 10,50 ± 1.0 µm

7. Mode field concentricity error ≤ 0,5 µm

8. Proof test ≥ 1 %

9. Fibre Curl (ROC) ≥ 4,0 m

10. Macrobend test on fibre at 1 550 nm ≤ 0,1 dB

Table 2 — Specifications for G.655 fibre

1 2

Attributes Value

1. adding diameter 125 µm ± 1,0µm

2. Cladding non-circularity ≤ 1,0 %

3. Attenuation coefficient at

a) 1 550 nm < 0,25 dB/km

b) 1 625 nm < 0,25 dB/km

4. Chromatic dispersion coefficient at

a) 1 550 nm < 6,0 ps/nm.km

b) 1 625 nm < 8,6 ps/nm.km

5. Polarization mode dispersion (PMD) ≤ 0,1 ps/√ km

6. Mode field diameter at

a) 1 550 nm 8,4 ± 0,6 µm

b) 1 625 nm 8,7 ± 0,6 µm

7. Mode field concentricity error ≤ 0,5 µm

8. Proof test ≥ 1 %

9. Fibre Curl (ROC) ≥ 2,0 m

10. Macrobend test on fibre at

a) 1 550 nm < 0,5 dB

b) 1 625 nm < 0,5 dB

13 NRS 061-1:2002

4.3.1.4 The fibre carrier shall be designed to minimize hydrogen absorption by the fibres.

4.3.1.5 The cable shall be designed such that when a cable is installed in accordance with themanufacturer’s instructions, no fibre shall be under any strain when the cable is subjected tooperating conditions.

4.3.1.6 There shall be no measurable long-term optical attenuation change due to the temperaturerise associated with fault current flowing in the earth wire or a lightning strike on the earth wire.

4.3.1.7 There shall be no fibre splices in any individual drum length of OPGW.

4.3.1.8 If a fibre carrier gel is required, it will be specified in schedule A.

4.3.2 Mechanical and electrical characteristics

The following mechanical and electrical characteristics of the OPGW shall be specified inschedule B:

Mechanical characteristics:

a) conductor material;

b) nominal cross-section;

c) actual cross-sectional area;

d) maximum overall diameter;

e) maximum mass per meter of cable;

f) rated tensile strength (RTS);

g) initial modulus of elasticity;

h) final modulus of elasticity;

i) maximum drum length; and

j) direction of lay of outer layer.

Electrical characteristics:

a) d.c. resistance at 20 oC/km; and

b) continuous current carrying capability 4.3.2.1 Full details of the cable construction shall beprovided in schedule B, including details of the measures taken to minimize hydrogen absorptionand water ingress by the fibres.

4.3.2.2 The system fault level will be specified in schedule A.

NRS 061-1:2002 14

4.4 Samples

4.4.1 If a sample is required, it shall be stated in schedule A.

4.4.2 Correctly labelled samples, reflecting the item number from schedule A, and the name of thetendering company, shall be delivered to the purchaser’s nominated offices not later than a weekbefore the closing of tenders.

4.4.3 The sample length shall be 1 m unless otherwise specified in schedule A. Samples ofoverhead optical ground-wires submitted shall be similar to the items offered.

4.4.4 Tenderers are required to note that tender documents shall not be included in parcelscontaining samples.

4.4.5 The purchaser reserves the right to submit samples to such tests as deemed reasonable andnecessary.

4.4.6 Unsuccessful tenderers shall collect their samples within one month of being notified thattheir tenders have not been successful, failing which, they shall be deemed to have waived all rightsto the samples and such samples not collected after one month from the date of such notification,shall become the property of the purchaser for disposal at his discretion.

5 Tests

5.1 Type Tests

5.1.1 General

The OPGW shall successfully pass the type tests in 5.1.2, 5.1.3 and 5.1.4. Type testing of a fibreoptic cable may be waived if type test results of cables of the same type and similar rating areavailable.

Copies of these type test reports shall be a prerequisite of tender compliance and shall be providedas part of the tender document. Suppliers are requested to provide copies of all type test reports ontests performed on the fibre, before and after assembly and drumming of the cable.

5.1.2 Optical tests

5.1.2.1 Attenuation and dispersion characteristics tests

During manufacture, both fibres shall be tested as per ITU-T Recommendation G.650 in both1 300 nm and 1 550 nm range for attenuation if G.652 fibre is specified, and at 1 550 nm forattenuation if G.655 fibre is specified. Measurement of the refractive index and dispersioncharacteristics shall be performed on a sampling basis to prove the suitability of the manufacturingprocess. The results shall be supplied to the user on request. Check for compliance with 4.2.3.

5.1.2.2 Proof test

The proof test shall be performed in accordance with IEC 60793-1-30. Check for compliance with4.2.4.

15 NRS 061-1:2002

5.1.2.3 Macro-bend resistance test

The macro-bend resistance test shall be performed in accordance with IEC 60793-1-47. Check forcompliance with 4.2.5.

5.1.3 Mechanical tests

5.1.3.1 Stress-strain test

A stress-strain test shall be performed to prove the capability of the OPGW under load conditions.The test shall be performed in accordance with annex B of IEC 61089, and the measuringtechniques shall be as specified in IEC 60794-1-1. The test shall be performed on samples of atleast 10 m in length, and the end fittings used shall be the system fittings, unless otherwise specifiedby the purchaser. Check for compliance with 4.2.9.

5.1.3.2 Crush test

The crush test shall be performed in accordance with the method specified in IEC 60794-1-2(method E3).

Perform the crush test by “sandwiching” the OPGW between two 50 mm x 50 mm flat plates andapplying a load of 10 kN for 1 min. Measure the optical attenuation at 1 550 nm and check forcompliance with 4.2.6.

5.1.3.3 Tensile performance test

This test is intended to determine the optical unit’s performance under a tensile load and shall beperformed using load conditions in accordance with annex B of IEC 61089, and the measuringtechniques as specified in IEC 60794-1-1. Check for compliance with 4.2.7.

5.1.3.4 Sheave Test

This test method shall use pulleys of an agreed upon diameter between purchaser andmanufacturer.

The OPGW cable shall be subjected to passing under tension over several metal pulleys and theovality of the cable and attenuation at 1 550 nm , measured.

5.1.3.4.1 Test set-up:

The test sample shall be terminated at each end with suitable end fittings. The test length of theoptical fibre shall be a minimum of 100 m. Fibre optical attenuation shall be measured using a lightsource and power meter connected to either end of the test fibre. An OTDR may be used, but theminimum optical fibre length shall be determined by the characteristics of the OTDR.

NRS 061-1:2002 16

5.1.3.4.2 Test conditions:

The general test conditions are as follows:

— pulling angle (α): 30 °, unless otherwise agreed between purchaser and manufacturer.

— tensile load: 15 % of RTS, unless otherwise agreed between purchaser and manufacturer.

— number of cycles:10 (one cycle being forwards and backwards).

— sheave diameter: to be agreed between purchaser and manufacturer.

5.1.3.4.3 Test procedure:

A 5 m minimum length of OPGW shall be pulled through the sheave for the required number ofcycles. Before the first pull, the beginning, midpoint and the end of this length shall be marked. Theoptical attenuation shall be measured throughout the test. After the test, the ovality of the OPGWand its components shall be determined and compared with their relative MAO at each of themarked points. Check for compliance with 4.2.8.

5.1.3.5 Impact test

This test shall be performed in accordance with IEC 60794-1-2 (method E4). The impact test shallbe performed by placing the end of a 20 mm diameter steel mandrel on the OPGW, and dropping a4 kg weight from a height of 100 mm onto the mandrel, repeated 20 times. Check for compliancewith 4.2.10.

5.1.3.6 Aeolian vibration test

The objective of this test is to assess the fatigue resistance of the OPGW under characteristic windinduced vibration. The test length of the OPGW shall be at least 100 m. The test sample shall besubjected to a minimum of 107 vibration cycles, at the nearest resonant frequency produced by a4,5 m/s wind. The peak-to-peak amplitude of the antinode shall be maintained at a level equal toone third of the conductor diameter. A final optical test shall be performed at least 2 h after thecompletion of the vibration test. Check for compliance with 4.2.11.

5.1.3.7 Conductor creep test

This test shall be performed in accordance with IEC 61395. Check for compliance with 4.2.12.

5.1.3.8 Temperature cycle test

A length of cable (minimum 200 m) shall be loosely coiled. A drum is not required, but, if a drum isused, there shall be a maximum of 2 layers of cable on the drum. The cable shall, for its own lengthbe exposed to the temperature changes, and therefore the barrel of the drum shall be ventilated.

The cable shall be placed in an environmental chamber. The temperature of the chamber shall becapable of programmable cycling between -10 °C and 70 °C.

The cable ends shall be outside the chamber and the fibres shall be spliced in cascade so as toachieve an optical fibre path length of between 1 000 m and 2 000 m. A temperature probe shall beplaced between the two layers of cable. The measurements from this temperature probe shall berecorded on a chart together with the trace of the chamber's temperature.

17 NRS 061-1:2002

The fibre shall be coupled to optical measurement equipment with stability such that a change of0, 05 dB/km can be reliably recorded over a period of one week.

The cable shall be subjected to five complete cycles. The attenuation of the cable shall be monitoredand recorded for the duration of the test and will be measured at both 1 550 nm and 1 310 nm. Check for compliance with 4.2.13.

5.1.3.9 Water ingress test

The water ingress test shall be performed in accordance with the method specified in IEC 60794-1-2(method F5), unless otherwise specified.

5.1.4 Electrical tests

5.1.4.1 Short-circuit test

This test is to appraise the effect of the instantaneous temperature rise on the optical characteristicsof the fibres, which is caused by short-circuit conditions. The ambient temperature during the testshall be the maximum temperature specified in schedule A (see item B.1).

The sample under test shall then be subjected to current pulses, so that the OPGW will be allowedto cool to within 5 ºC from the ambient temperature between each current pulse. The opticalattenuation of the test fibres shall be monitored continuously. Check for compliance with 4.2.14.

5.1.4.2 Lightning test

The lightning test shall be performed by subjecting the mid-point of a 10 m long sample of OPGW toa simulated lightning strike. This test shall be performed in accordance with annex C of IEC 61312-1 and consists of two components, namely:

a) Initial strike.

Parameters Protection level Tolerance

Peak current I (kA) 200 +/−10 %

Charge Qs (C) 100 +/−20 %

Specific Energy W/R (MJ/Ω) 10 +/−35 %

b) Continuing current.

Parameters Protection level Tolerance

Charge Ql (C) 200 +/−20 %

Duration T (s) 0,5 +/−10 %

The length of the applied arc shall be greater than 50 mm.

The fibre attenuation should be evaluated by measuring the end-to-end attenuation when all thefibres in the cable have been concatenated. Check for compliance with 4.2.15.

NRS 061-1:2002 18

5.2 Routine Tests

The purchaser shall require an inspector to be present when these final measurements areperformed. The purchaser’s attendance shall not relieve the supplier of his responsibility for thesatisfactory performance of the cable during subsequent testing at site, and thereafter to the end ofthe warranty period.

5.3 Sample Tests

The following sample tests shall be done:

a) on wire before stranding:

— as per IEC 60889 and IEC 61232;

b) on the completed cable:

— cross-sectional area;

— overall diameter;

— surface condition;

— lay ratio and direction of lay; and

— dc resistance.

6 Marking, labelling, packaging and documentation

6.1 Marking and labelling

Each reel shall be labelled with at least one water-resistant tag, containing the following minimuminformation:

a) manufacturer’s name;

b) place of manufacture;

c) OPGW size and number of fibres;

d) OPGW shipped length (standard or specified);

e) gross tare and net weight;

f) drum number;

g) order/contract number;

h) type of cable;

i) destination;

j) stock code;

19 NRS 061-1:2002

k) the words “ Not to be laid flat” unless the manufacturer guarantees that the drum or reel may belaid flat without damage to the OPGW;

l) an arrow or the words “Roll this way “ shall be used (to indicate the direction in which the drum orreel is to be rolled in order to prevent the OPGW from unwinding) unless the manufacturerguarantees that the drum or reel may be rolled in either direction without damage to the OPGW;and

m) the outer end of the cable shall be accessible for testing purposes.

6.2 Packaging

6.2.1 OPGW shall be supplied tightly and uniformly wound onto wooden cable reels. The woundlength of the OPGW on each reel shall be as specified in B.6 of annex B.

6.2.2 The reel shall be of such construction that no damage to the OPGW will occur duringshipping and handling and, be fitted with wooden battens around the periphery of the drum to ensureadequate protection. The outer layer of the OPGW on the reel shall be protected by a water-resistantwrapping over the exposed surface, to prevent ingress of moisture and dirt during shipping andhandling.

6.2.3 Each end of the OPGW shall be properly sealed to prevent the ingress of moisture into theoptical fibre unit during shipment or storage, i.e. heat shrink end-cap to be used for sealing.

6.3 Documentation

6.3.1 If so specified in schedule A, the following information shall be provided:

a) index;

b) cable type test reports;

c) routine test reports;

d) details of cable design; and

e) details of fibre numbering and colour coding.

6.3.2 All documentation called for shall be provided in hard-covered ring files that can open flat onany page and shall comply with the following requirements:

a) all documentation including type test reports, shall be supplied in triplicate in English;

b) all documentation shall be in standard A4 size;

c) any drawings and descriptions included shall conform to the standard A4 size. Drawings, whichmust be folded in two directions, are not acceptable (295 mm x 210 mm). Larger drawings shallbe folded in a single panel along the 210 mm axis; and

d) different sections of the documentation shall be separated by means of thumb-tag fileseparators.

e) an electronic format shall also be accepted, subject to approval.

NRS 061-1:2002 20

Annex A(informative)

Guide to purchasers on preparing an enquiry

A.1 General

A model form is given in annex B to provide the purchaser with a convenient aid to purchasing. Theuse of this form is intended to obviate the need for preparing a detailed technical specification.

The purchaser need only specify compliance with this specification, provide the tenderers withdetails of his particular requirements, and set out the information he requires the tenderer to provide,as indicated below.

A.2 Schedules

A.2.1 General

The model form in annex B provides the purchaser with examples of a schedule A and aschedule B. In his enquiry, the purchaser should provide his own schedule A and schedule B, basedon these examples.

A.2.2 Schedule A

Schedule A lists the requirements to be specified by the purchaser in enquiries and orders. Theserequirements include references to the relevant subclauses in this specification to assist in compilingthe schedules.

Where the text of any referenced standards stipulates that the purchaser shall indicate hisrequirements, these requirements should also be specified in schedule A.

The purchaser should set out his particular requirements and choices in his own schedule A.

A.2.3 Schedule B

The purchaser should draw up his own schedule B (based on the schedule B in the model form), andrequire the tenderer to fill in this schedule. By doing this, the tenderer will be stating compliance withthis specification and will provide the information the purchaser has requested.

NOTE 1 Where this specification allows the purchaser to make a choice, the example of schedule A (in the model form inannex B) lists the preferred items/values/quantities. In the interests of standardisation, purchasers are encouraged not todeviate from these preferences.

NOTE 2 When preparing his own schedule A and schedule B from the examples in the model form in annex B, thepurchaser need only include the items he considers to be relevant or necessary.

NOTE 3 These schedules, when completed, become normative annexes to the enquiry specification.

21 NRS 061-1:2002

Annex A(concluded)

A.3 Commercial conditions

A purchaser will furthermore need to indicate the commercial conditions applicable and draw up aprice schedule. Requirements for delivery, storage, packing and marking should be attended to inthis part of the enquiry.

A.4 Quality assurance

This specification does not cover the purchaser's possible requirements in respect of qualityassurance, quality control, inspections, etc., since each purchaser needs to consider the criticality ofthe application of each component, his own policy towards these matters, etc. Purchasers arereferred to SABS ISO 9001:2000 for guidance.

A.5 Testing

Attention should be paid to the subject of tests and the related costs. Tests should be carried out byan accredited laboratory and tenderers should be requested to provide assurances on this point.Price schedules should be so drawn up and covering letters so worded that the costs of all servicessuch as tests, delivery and spares are declared and allowed for in the tender.

Before type tests, routine tests and sample tests are carried out, the number of samples used andthe frequency of sampling should be agreed upon with the supplier.

A.6 Revision of standards used as normative references

This specification, as has been indicated, is based on a set of defined standards, which may havebeen revised or amended. Most purchasers will, in principle, wish to employ the latest standards. Itis recommended that an approach to this question be to secure an undertaking from a supplier toreview the latest versions and amendments and to incorporate these where possible and agreeableto both parties. A blanket commitment to work to the "latest" versions of standards creates legaldifficulties of interpretation and risks for both parties and should be properly assessed. Thisinvariably cannot be done in the time available.

NRS 061-1:2002 22

Annex B(informative)

Model form for schedules A and B

This model form is provided as a convenient aid to purchasing. Guidance on preparing an enquiryusing this form is given in annex A.

Schedule A: Purchaser's specific requirements andSchedule B: Particulars of equipment to be supplied.

Item Clause Description Schedule A Schedule B

B.1 4.1.4 Grease conductor as per IEC 61089? Yes/No __________ xxxxxxxxxx4.1.5 Pollution level, if other than heavy __________ xxxxxxxxxx

Maximum temperature, if other than 50 °C °C __________ xxxxxxxxxx

Minimum temperature, if other than –10 °C °C __________ xxxxxxxxxxMaximum wind speed, if other than 36 m/s m/s __________ xxxxxxxxxxRoute altitude, if other than 200 m m __________ xxxxxxxxxx

4.1.6 Name of manufacturer xxxxxxxxxx __________Place of manufacturer xxxxxxxxxx __________Manufacturer’s reference number xxxxxxxxxx __________

B.2 4.2.1.2 Type of fibre carrier __________ xxxxxxxxxx4.2.2.1 OPGW 1 s current rating; kA __________ xxxxxxxxxx4.2.2.2 Stranding and wire diameter xxxxxxxxxx __________

B.3 4.3.1.1 Number of fibres __________ xxxxxxxxxx4.3.1.3 Cladding configuration (depressed or

matched). If other, state details. __________ xxxxxxxxxx4.3.1.8 Is a fibre carrier gel required? Yes/No __________ xxxxxxxxxx4.3.2 Conductor material xxxxxxxxxx __________

Nominal cross-section xxxxxxxxxx __________Actual cross-sectional area xxxxxxxxxx __________Maximum overall diameter xxxxxxxxxx __________Maximum mass per meter of cable kg/m xxxxxxxxxx __________Rated tensile strength (RTS) xxxxxxxxxx __________Initial modulus of elasticity xxxxxxxxxx __________Direction of lay of outer layer xxxxxxxxxx __________DC resistance at 20 oC / km Ω xxxxxxxxxx __________Continuous current carrying capability A xxxxxxxxxx __________

4.3.2.1 Complete details of cable construction, xxxxxxxxxx __________including measures to minimise hydrogenabsorption and water ingress.

4.3.2.2 System fault level kA __________ xxxxxxxxxxB.4 4.4.1 Is a sample required? Yes/No __________ xxxxxxxxxx

4.4.3 Length of sample, if not 1 m __________ xxxxxxxxxxB.5 6.3 Is documentation required? Yes/No __________ xxxxxxxxxxB.6 6.2.1 Wound length of OPGW xxxxxxxxxx __________

23 NRS 061-1:2002

Bibliography

SABS ISO 9001:2000, Quality management systems — Requirements.

sabs pta