IEC 60502-2:2005

 
Power cables with extruded insulation and their
accessories for rated voltages
from 1 kV (Um = 1,2 kV) up to 30 kV (Um = 36 kV) –
Part 2:
Cables for rated voltages from 6 kV (Um = 7,2 kV)
up to 30 kV (Um = 36 kV)
 
 
 
Reference number
IEC 60502-2:2005(E)
INTERNATIONAL
STANDARD
IEC
60502-2
  Second edition
2005-03
 
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Power cables with extruded insulation and their
accessories for rated voltages
from 1 kV (Um = 1,2 kV) up to 30 kV (Um = 36 kV) –
Part 2:
Cables for rated voltages from 6 kV (Um = 7,2 kV)
up to 30 kV (Um = 36 kV)
 
For price, see current catalogue
 IEC 2005 Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical,
including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission,  3, rue  de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch  Web: www.iec.ch
INTERNATIONAL
STANDARD
IEC
60502-2
  Second edition
2005-03
 
XC  Commission Electrotechnique Internationale
International Electrotechnical Commission
Международная Электротехническая Комиссия
PRICE CODE 60502-2  IEC:2005 – 3 –
 
CONTENTS
FOREWORD......................................................................................................................13
 
1  Scope..........................................................................................................................17
2  Normative references...................................................................................................17
3  Terms and definitions...................................................................................................19
3.1  Definitions of dimensional values (thicknesses, cross-sections, etc.)....................19
3.2  Definitions concerning the tests...........................................................................21
4  Voltage designations and materials..............................................................................21
4.1  Rated voltages....................................................................................................21
4.2  Insulating compounds..........................................................................................23
4.3  Sheathing compounds .........................................................................................25
5  Conductors...................................................................................................................27
6  Insulation.....................................................................................................................27
6.1  Material...............................................................................................................27
6.2  Insulation thickness.............................................................................................27
7  Screening.....................................................................................................................29
7.1  Conductor screen................................................................................................31
7.2  Insulation screen.................................................................................................31
8  Assembly of three-core cables, inner coverings and fillers ............................................31
8.1  Inner coverings and fillers....................................................................................31
8.2  Cables having a collective metallic layer (see Clause 9).......................................33
8.3  Cables having a metallic layer over each individual core  (see Clause 10)............33
9  Metallic layers for single-core and three-core cables.....................................................35
10  Metallic screen.............................................................................................................35
10.1  Construction........................................................................................................35
10.2  Requirements......................................................................................................35
10.3  Metallic screens not associated with semi-conducting layers................................35
11  Concentric conductor....................................................................................................35
11.1  Construction........................................................................................................35
11.2  Requirements......................................................................................................37
11.3  Application..........................................................................................................37
12  Metallic sheath.............................................................................................................37
12.1  Lead sheath........................................................................................................37
12.2  Other metallic sheaths.........................................................................................37
13  Metallic armour ............................................................................................................37
13.1  Types of metallic armour.....................................................................................37
13.2  Materials.............................................................................................................39
13.3  Application of armour...........................................................................................39
13.4  Dimensions of the armour wires and armour tapes...............................................41
13.5  Correlation between cable diameters and armour dimensions..............................41
13.6  Round or flat wire armour....................................................................................43
13.7  Double tape armour .............................................................................................43 60502-2  IEC:2005 – 5 –
 
14  Oversheath..................................................................................................................43
14.1  General...............................................................................................................43
14.2  Material...............................................................................................................45
14.3  Thickness............................................................................................................45
15  Test conditions .............................................................................................................45
15.1  Ambient temperature...........................................................................................45
15.2  Frequency and waveform of power frequency test voltages..................................45
15.3  Waveform of impulse test voltages.......................................................................45
16  Routine tests................................................................................................................47
16.1  General...............................................................................................................47
16.2  Electrical resistance of conductors.......................................................................47
16.3  Partial discharge test...........................................................................................47
16.4  Voltage test.........................................................................................................47
17  Sample tests................................................................................................................49
17.1  General...............................................................................................................49
17.2  Frequency of sample tests...................................................................................51
17.3  Repetition of tests...............................................................................................51
17.4  Conductor examination........................................................................................51
17.5  Measurement of thickness of insulation and of non-metallic sheaths 
(including extruded separation sheaths, but excluding inner extruded
coverings)...........................................................................................................51
17.6  Measurement of thickness of lead sheath............................................................53
17.7  Measurement of armour wires and tapes..............................................................55
17.8  Measurement of external diameter.......................................................................55
17.9  Voltage test for 4 h..............................................................................................55
17.10 Hot set test for EPR, HEPR and XLPE insulations and elastomeric sheaths..........57
18  Type tests, electrical....................................................................................................57
18.1  Cables having conductor screens and insulation screens.....................................57
18.2  Cables of rated voltage 3,6/6 (7,2) kV having unscreened insulation....................65
19  Type tests, non-electrical..............................................................................................69
19.1  Measurement of thickness of insulation................................................................69
19.2  Measurement of thickness of non-metallic sheaths (including extruded
separation sheaths, but excluding inner coverings)..............................................69
19.3  Tests for determining the mechanical properties of insulation before and
after ageing.........................................................................................................69
19.4  Tests for determining the mechanical properties of non-metallic sheaths
before and after ageing.......................................................................................71
19.5  Additional ageing test on pieces of completed cables...........................................71
19.6  Loss of mass test on PVC sheaths of type ST2 ....................................................73
19.7  Pressure test at high temperature on insulations and non-metallic sheaths...........73
19.8  Test on PVC insulation and sheaths at low temperatures.....................................73
19.9  Test for resistance of PVC insulation and sheaths to cracking (heat shock
test)....................................................................................................................73
19.10 Ozone resistance test for EPR and HEPR insulations...........................................75
19.11 Hot set test for EPR, HEPR and XLPE insulations and elastomeric sheaths..........75
19.12 Oil immersion test for elastomeric sheaths...........................................................75
19.13 Water absorption test on insulation......................................................................75 60502-2  IEC:2005 – 7 –
 
19.14  Flame spread test on single cables ......................................................................75
19.15 Measurement of carbon black content of black PE oversheaths............................75
19.16 Shrinkage test for XLPE insulation.......................................................................77
19.17  Thermal stability test for PVC insulation...............................................................77
19.18 Determination of hardness of HEPR insulation.....................................................77
19.19 Determination of the elastic modulus of HEPR insulation......................................77
19.20 Shrinkage test for PE oversheaths .......................................................................77
19.21 Strippability test for insulation screen ..................................................................79
19.22 Water penetration test.........................................................................................79
20  Electrical tests after installation....................................................................................81
20.1  D.C. voltage test of the oversheath ......................................................................81
20.2  Insulation test......................................................................................................81
 
Annex A (normative)  Fictitious calculation method for determination of dimensions of
protective coverings............................................................................................................93
Annex B (informative)  Tabulated continuous current ratings for cables having
extruded insulation and a rated voltage from 3,6/6 kV up to 18/30 kV................................103
Annex C (normative)  Rounding of numbers......................................................................143
Annex D (normative)  Method of measuring resistivity of semi-conducting screens............145
Annex E (normative)  Determination of hardness of HEPR insulations...............................149
Annex F (normative)  Water penetration test .....................................................................153
 
Bibliography .....................................................................................................................157
 
Figure B.1 – Single-core cables in air................................................................................105
Figure B.2 – Single-core cables buried direct ....................................................................107
Figure B.3 – Single-core cables in earthenware ducts .......................................................107
Figure B.4 – Three-core cables.........................................................................................109
Figure D.1a – Measurement of the volume resistivity of the conductor screen....................147
Figure D.1b – Measurement of the volume resistivity of the insulation screen....................147
Figure D.1 – Preparation of samples for measurement of resistivity of conductor and
insulation screens.............................................................................................................147
Figure E.1 – Test on surfaces of large radius of curvature.................................................151
Figure E.2 – Test on surfaces of small radius of curvature.................................................151
Figure F.1 – Schematic diagram of apparatus for water penetration test............................155
 
Table 1 – Recommended rated voltages U0 ........................................................................23
Table 2 – Insulating compounds..........................................................................................25
Table 3 – Maximum conductor temperatures for different types of insulating compound.......25
Table 4 – Maximum conductor temperatures for different types  of sheathing
compound..........................................................................................................................27
Table 5 – Nominal thickness of PVC/B insulation................................................................27
Table 6 – Nominal thickness of cross-linked polyethylene (XLPE) insulation........................29 60502-2  IEC:2005 – 9 –
 
Table 7 – Nominal thickness of ethylene propylene rubber (EPR) and hard ethylene
propylene rubber (HEPR) insulation....................................................................................29
Table 8 – Thickness of extruded inner covering...................................................................33
Table 9 – Nominal diameter of round armour wires..............................................................41
Table 10 – Nominal thickness of armour tapes....................................................................43
Table 11 – Routine test voltages.........................................................................................49
Table 12 – Number of samples for sample tests..................................................................51
Table 13 – Sample test voltages.........................................................................................57
Table 14 – Impulse voltages...............................................................................................63
Table 15 – Electrical type test requirements for insulating compounds.................................81
Table 16 – Non-electrical type tests (see Tables 17 to 23)..................................................83
Table 17 – Test requirements for mechanical characteristics of insulating compounds 
(before and after ageing)....................................................................................................85
Table 18 – Test requirements for particular characteristics  for PVC insulating
compound..........................................................................................................................85
Table 19 – Test requirements for particular characteristics  of various thermosetting
insulating compounds.........................................................................................................87
Table 20 – Test requirements for mechanical characteristics of sheathing compounds 
(before and after ageing)....................................................................................................87
Table 21 – Test requirements for particular characteristics  for PVC sheathing
compounds.........................................................................................................................89
Table 22 – Test requirements for particular characteristics  of PE (thermoplastic
polyethylene) sheathing compounds ...................................................................................89
Table 23 – Test requirements for particular characteristics  of elastomeric sheathing
compound..........................................................................................................................91
Table A.1 – Fictitious diameter of conductor........................................................................95
Table A.2 – Increase of diameter for concentric conductors and metallic screens ................97
Table A.3 – Increase of diameter for additional bedding ....................................................101
Table B.1 – Nominal screen cross-sectional areas............................................................103
Table B.2 – Current ratings for single-core cables with XLPE insulation   Rated voltage
3,6/6 kV to 18/30 kV * Copper conductor...........................................................................111
Table B.3 – Current ratings for single-core cables with XLPE insulation   Rated voltage
3,6/6 kV to 18/30 kV * Aluminium conductor ......................................................................113
Table B.4 – Current ratings for single-core cables with EPR insulation   Rated voltage
3,6/6 kV to 18/30 kV * Copper conductor...........................................................................115
Table B.5 – Current ratings for single-core cables with EPR insulation   Rated voltage
3,6/6 kV to 18/30 kV * Aluminium conductor ......................................................................117
Table B.6 – Current rating for three-core XLPE insulated cables Rated voltage 3,6/6
kV to 18/30 kV *  Copper conductor Armoured and unarmoured........................................119
Table B.7 – Current rating for three-core XLPE insulated cables Rated voltage 3,6/6
kV to 18/30 kV *  Aluminium conductor Armoured and unarmoured....................................121
Table B.8 – Current rating for three-core EPR insulated cables  Rated voltage 3,6/6 kV
to 18/30 kV * Copper conductor Armoured and unarmoured ..............................................123 60502-2  IEC:2005 – 11 –
 
Table B.9 – Current rating for three-core EPR insulated cables  Rated voltage 3,6/6 kV
to 18/30 kV * Aluminium conductor Armoured and unarmoured..........................................125
Table B.10 – Correction factors for ambient air temperatures other than 30 °C..................127
Table B.11 – Correction factors for ambient ground temperatures other than 20 °C...........127
Table B.12 – Correction factors for depths of laying  other than 0,8 m for direct buried
cables..............................................................................................................................127
Table B.13 – Correction factors for depths of laying  other than 0,8 m for cables in
ducts................................................................................................................................129
Table B.14 – Correction factors for soil thermal resistivities  other than 1,5 K•m/W for
direct buried single-core cables........................................................................................129
Table B.15 – Correction factors for soil thermal resistivities  other than 1,5 K•m/W
single-core cables in buried ducts.....................................................................................131
Table B.16 – Correction factors for soil thermal resistivities  other than 1,5 K•m/W for
direct buried three-core cables.........................................................................................131
Table B.17 – Correction factors for soil thermal resistivities  other than 1,5 K•m/W for
three-core cables in ducts.................................................................................................133
Table B.18 – Correction factors for groups of 3-core cables  in horizontal formation
laid direct in the ground....................................................................................................133
Table B.19 – Correction factors for groups of 3-phase circuits  of single-core cables
laid direct in the ground....................................................................................................135
Table B.20 – Correction factors for groups of 3-core cables  in single way ducts in
horizontal formation..........................................................................................................135
Table B.21 – Correction factors for groups of 3-phase circuits  of single-core cables in
single-way ducts...............................................................................................................137
Table B.22 – Reduction factors for groups of more than one multi-core cable in air To
be applied to the current-carrying capacity for one multi-core cable in free air...................139
Table B.23 – Reduction factors for groups of more than one circuit  of single-core
cables (Note 2) To be applied to the current-carrying capacity for one circuit  of single-
core cables in free air.......................................................................................................141 60502-2  IEC:2005 – 13 –
 
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
 
POWER CABLES WITH EXTRUDED INSULATION AND THEIR ACCESSORIES
FOR RATED VOLTAGES FROM 1 kV (Um = 1,2 kV) UP TO 30 kV (Um = 36 kV) –
 
Part 2: Cables for rated voltages from 6 kV
(Um = 7,2 kV) up to 30 kV (Um = 36 kV)