IEC 60364-5-52

SLOVENSKI SIST IEC 60364-5-52:2006

STANDARD
september 2006
Električne inštalacije zgradb – 5-52. del: Izbira in namestitev električne
opreme – Inštalacijski sistemi
Electrical installations of buildings - Part 5-52: Selection and erection of electrical
equipment - Wiring systems
ICS 91.140.50 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

Edition 2.0 2001-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical installations of buildings –
Part 5-52: Selection and erection of electrical equipment – Wiring systems

Installations électriques des bâtiments –
Partie 5-52: Choix et mise en œuvre des matériels électriques – Canalisations

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 13.260; 91.140.50 ISBN 2-8318-5879-8

– 2 – 60364-5-52 © IEC:2001
CONTENTS
FOREWORD.5

520 Introduction.6
520.1 Scope.6
520.2 Normative references.6
520.3 General.13
521 Types of wiring systems .13
522 Selection and erection of wiring systems in relation to external influences .15
522.1 Ambient temperature (AA).15
522.2 External heat sources.15
522.3 Presence of water (AD) .15
522.4 Presence of solid foreign bodies (AE) .16
522.5 Presence of corrosive or polluting substances (AF).16
522.6 Impact (AG).16
522.7 Vibration (AH).16
522.8 Other mechanical stresses (AJ).16
522.9 Presence of flora and/or mould growth (AK) .17
522.10 Presence of fauna (AL) .17
522.11 Solar radiation (AN) .17
522.12 Seismic effects (AP).18
522.13 Wind (AS) .18
522.14 Nature of processed or stored materials (BE) .18
522.15 Building design (CB) .18
523 Current-carrying capacities.18
524 Cross-sectional areas of conductors.39
525 Voltage drop in consumers' installations.21
526 Electrical connections.21
527 Selection and erection of wiring systems to minimize the spread of fire.22
527.1 Precautions within a fire-segregated compartment .22
527.2 Sealing of wiring system penetrations .22
528 Proximity of wiring systems to other services .23
528.1 Proximity to electrical services .23
528.2 Proximity to non-electrical services .24
529 Selection and erection of wiring systems in relation to maintainability,
including cleaning .24

Annex A (normative) Current-carrying capacities .25
Annex B (informative) Example of a method of simplification of the tables of clause 523.51
Annex C (informative) Formulae to express current-carrying capacities .55
Annex D (informative) Effect of harmonic currents on balanced three-phase systems .58
Annex E (informative) IEC 60364 – Parts 1 to 6: Restructuring .60
Bibliography.64

60364-5-52 © IEC:2001 – 3 –
Table 52-1 (52F) – Selection of wiring systems.8
Table 52-2 (52G) – Erection of wiring systems.8
Table 52-3 (52H) – Examples of methods of installation providing instructions for obtaining
current-carrying capacity .9
Table 52-4 (52-A) – Maximum operating temperatures for types of insulation.18
Table 52-5 (52J) – Minimum cross-sectional area of conductors .21
Table A.52-1 (52-B1) – Schedule of reference methods of installation which form the basis
of the tabulated current-carrying capacities.30
Table A.52-2 (52-C1) – Current-carrying capacities in amperes for methods of installation
in table A.52-1 (52-B1) – PVC insulation/two loaded conductors/copper or aluminium –
Conductor temperature: 70 °C/Ambient temperature: 30 °C in air, 20 °C in ground .32
Table A.52-3 (52-C2) – Current-carrying capacities in amperes for methods of installation
in table A.52-1 (52-B1) – XLPE or EPR insulation/two loaded conductors/copper or
aluminium – Conductor temperature: 90 °C/Ambient temperature: 30 °C in air, 20 °C
in ground .33
Table A.52-4 (52-C3) – Current-carrying capacities in amperes for methods of installation
in table A.52-1 (52-B1) – PVC insulation/three loaded conductors/copper or aluminium –
Conductor temperature: 70 °C/Ambient temperature: 30 °C in air, 20 °C in ground .34
Table A.52-5 (52-C4) – Current-carrying capacities in amperes for methods of installation
in table A.52-1 (52-B1) – XLPE or EPR insulation/three loaded conductors/copper or
aluminium – Conductor temperature: 90 °C/Ambient temperature: 30 °C in air, 20 °C
in ground .35
Table A.52-6 (52-C5) – Current-carrying capacities in amperes for installation method C
of table A.52-1 (52-B1) – Mineral insulation/copper conductors and sheath – PVC covered
or bare exposed to touch (see note 2) Metallic sheath temperature: 70 °C/Reference
ambient temperature: 30 °C .36
Table A.52-7 (52-C6) – Current-carrying capacities in amperes for installation method C
of table A.52-1 (52-B1) – Mineral insulation/copper conductors and sheath – Bare cable
not exposed to touch and not in contact with combustible material Metallic sheath
temperature: 105 °C/Reference ambient temperature: 30 °C.37
Table A.52-8 (52-C7) – Current-carrying capacities in amperes for installation methods E,
F and G of table A.52-1 (52-B1) – Mineral insulation/Copper conductors and sheath/PVC
covered or bare exposed to touch (see note 2) Metallic sheath temperature:
70 °C/Reference ambient temperature: 30 °C .38
Table A.52-9 (52-C8) – Current-carrying capacities in amperes for installation methods E,
F and G of table A.52-1 (52-B1) – Mineral insulation/Copper conductors and sheath/ Bare
cable not exposed to touch (see note 2) Metallic sheath temperature: 105 °C/Reference
ambient temperature: 30 °C .39
Table A.52-10 (52-C9) – Current-carrying capacities in amperes for installation methods E,
F and G of table A.52-1 (52-B1) – PVC insulation/Copper conductors Conductor
temperature: 70 °C/Reference ambient temperature: 30 °C.40
Table A.52-11 (52-C10) – Current-carrying capacities in amperes for installation
methods E, F and G of table A.52-1 (52-B1) – PVC insulation/Aluminium conductors
Conductor temperature: 70 °C/Reference ambient temperature: 30 °C.41
Table A.52-12 (52-C11) – Current-carrying capacities in amperes for installation
methods E, F and G of table A.52-1 (52-B1) – XLPE or EPR insulation/Copper
conductors – Conductor temperature: 90 °C/Reference ambient temperature: 30 °C.42
Table A.52-13 (52-C12) – Current-carrying capacities in amperes for installation
methods E, F and G of table A.52-1 (52-B1) – XLPE or EPR insulation/Aluminium
conductors Conductor temperature: 90 °C/Reference ambient temperature: 30 °C.43
Table A.52-14 (52-D1) – Correction factor for ambient air temperatures other than 30 °C
to be applied to the current-carrying capacities for cables in the air .44

– 4 – 60364-5-52 © IEC:2001
Table A.52-15 (52-D2) – Correction factors for ambient ground temperatures other than
20 °C to be applied to the current-carrying capacities for cables in ducts in the ground.45
Table A.52-16 (52-D3) – Correction factors for cables in buried ducts for soil thermal
resistivities other than 2,5 K·m/W to be applied to the current-carrying capacities for
reference method D .45
Table A.52-17 (52-E1) – Reduction factors for groups of more than one circuit or of more
than one multi-core cable to be used with current carrying capacities of tables A.52-2
(52-C1) to A.52-13 (52-C12) .46
Table A.52-18 (52-E2) – Reduction factors for more than one circuit, cables laid directly
in the ground – Installation method D in tables A.52-2 (52-C1) to A.52-5 (52-C4) –
Single-core or multi-core cables.47
Table A.52-19 (52-E3) – Reduction factors for more than one circuit, cables laid in
ducts in the ground – Installation method D in tables A.52-2 (52-C1) to A.52-5 (52-C4) .48
Table A.52-20 (52-E4) – Reduction factors for group of more than one multi-core cable to
be applied to reference ratings for multi-core cables in free air – Method of installation E
in tables A.52-8 (52-C7) to A.52-13 (52-C12) .49
Table A.52-21 (52-E5) – Reduction factors for groups of more than one circuit of single-
core cables (note 2) to be applied to reference rating for one circuit of single-core cables
in free air – Method of installation F in tables A.52-8 (52-C7) to A.52-13) (52-C12).50
Table B.52-1 (A.52-1) – Current-carrying capacity in amperes .52
Table B.52-2 (A.52-2) – Current-carrying capacities (in amperes) .53
Table B.52-3 (A.52-3) – Reduction factors for groups of several circuits or of several
multi-core cables (to be used with current-carrying capacities of table B.52-1) (A.52-1) .54
Table C.52-1 (B.52-1) – Table of coefficients and exponents .56
Table D.52-1 (C.52-1) – Reduction factors for harmonic currents in four-core and
five-core cables .59
Table E.1 – Relationship between re-structured and original parts .60
Table E.2 – Relationship between new and old clause numbering.62

60364-5-52 © IEC:2001 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
–––––––––
ELECTRICAL INSTALLATIONS OF BUILDINGS –
Part 5-52: Selection and erection of electrical equipment –
Wiring systems
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60364-5-52 has been prepared by IEC technical committee 64:
Electrical installations and protection against electric shock.
The IEC 60364 series (parts 1 to 6), is currently being restructured, without any technical
changes, into a more simple form (see annex E).
According to a unanimous decision by the Committee of Action (CA/1720/RV (2000-03-21)),
the restructured parts of IEC 60364 have not been submitted to National Committees for
approval.
The text of this second edition of IEC 60364-5-52 is compiled from and replaces
– part 5-52, first edition (1993) and its amendment 1 (1997);
– part 5-523, second edition (1999).
This publication has been drafted, as close as possible, in accordance with the
ISO/IEC Directives, Part 3.
Annex A forms an integral part of this standard.
Annexes B, C, D and E are for information only.
The committee has decided that the contents of this publication will remain unchanged
until 2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 6 – 60364-5-52 © IEC:2001
ELECTRICAL INSTALLATIONS OF BUILDINGS –
Part 5-52: Selection and erection of electrical equipment –
Wiring systems
520 Introduction
520.1 Scope
Part 5-52 of IEC 60364 deals with the selection and erection of wiring systems.
NOTE This standard also applies in general to protective conductors, while IEC 60364-5-54 contains further
requirements for those conductors.
520.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60364. For dated references, subsequent amend-
ments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this part of IEC 60364 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
IEC 60228: 1978, Conductors of insulated cables
IEC 60287-1-1:1994, Electric cables – Calculation of the current rating – Part 1: Current rating
equations (100 % load factor) and calculation of losses – Section 1: General
IEC 60287-2-1:1994, Electric cables – Calculation of the current rating – Part 2: Thermal
resistance – Section 1: Calculation of thermal resistance
IEC 60287-3-1:1995, Electric cables – Calculation of the current rating – Part 3: Sections on
1)
operating conditions – Section 1: Reference operating conditions and selection of cable type
IEC 60332-1:1993, Tests on electric cables under fire conditions – Part 1: Test on a single
vertical insulated wire or cable
IEC 60332-3-24:2000, Tests on electric cables under fire conditions – Part 3-24: Test for
vertical flame spread of vertically-mounted bunched wire or cables – Category C
IEC 60439-2:2000, Low-voltage switchgear and controlgear assemblies – Part 2: Particular
requirements for busbar trunking systems (busways)
2)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60614 (all parts), Specification for conduits for electrical installations
IEC 61200-52:1993, Electrical installation guide – Part 52: Selection and erection of electrical
equipment – Wiring systems
ISO 834 (all parts) Fire-resistance tests – Elements of building construction
________
1)
A consoldated edition 1.1 exists (1999) that includes IEC 60287-3-1 (1995) and its amendment 1 (1999).
2)
A consoldated edition 2.1 exists (2001) that includes IEC 60529 (1989) and its amendment 1 (1999).

60364-5-52 © IEC:2001 – 7 –
520.3 General
Consideration shall be given to the application of the fundamental principles of IEC 60364-1
as it applies to cables and conductors, to their termination and/or jointing, to their associated
supports or suspensions and their enclosures or methods of protection against external
influences.
521 Types of wiring systems
521.1 The method of installation of a wiring system in relation to the type of conductor or
cable used shall be in accordance with table 52-1, provided the external influences are
covered by the requirements of the relevant product standards.
521.2 The method of installation of a wiring system in relation to the situation concerned
shall be in accordance with table 52-2.
521.3 Examples of wiring systems together with reference to the appropriate table of current-
carrying capacity are shown in table 52-3.
NOTE 1  Other types of wiring systems, not covered in this standard, may be used provided they comply with the
general rules of this standard.
NOTE 2  Table 52-3 gives the reference method of installation where it is considered that the same current-
carrying capacities can safely be used. It is not implied that all these items are necessarily recognized in national
rules of all countries.
521.4 Busbar trunking systems
Busbar trunking systems shall comply with IEC 60439-2 and shall be installed in accordance
with the manufacturer's instructions. The installation shall be in accordance with the
requirements of clauses 522 (with the exception of 522.1.1, 522.3.3, 522.8.7, 522.8.8
and 522.8.9), 525, 526, 527 and 528.
521.5 AC circuits
Conductors of a.c. circuits installed in ferromagnetic enclosures shall be arranged so that all
conductors of each circuit are contained in the same enclosure.
NOTE  If this condition is not fulfilled, overheating and excessive voltage drop may occur due to inductive effects.

– 8 – 60364-5-52 © IEC:2001
Table 52-1 (52F) – Selection of wiring systems
Method of installation
Conductors and Cable
cables trunking
Cable ladder
(including
Without Clipped Cable Cable tray On in- Support
Conduit skirting
sulators wire
fixings direct ducting Cable
trunking,
brackets
flush floor
trunking)
Bare conductors – – – – – – + –
Insulated – – + + + – + –
conductors
Sheathed Multi- + + + + + + 0 +
cables core
(including
Single 0 + + + + + 0 +
armoured
-core
and
mineral
insulated)
+ Permitted.
– Not permitted.
0 Not applicable, or not normally used in practice.

Table 52-2 (52G) – Erection of wiring systems
Method of installation
Cable
trunking
Cable ladder,
Situations (including
Without With Cable On Support
Conduit skirting cable tray, cable
fixings fixings ducting insulators wire
trunking, brackets
flush floor
trunking)
Building voids 40, 46, 0 15,16, – 43 30, 31, 32, 33, 34 – –
15, 16 41,42
Cable channel 56 56 54, 55 0 44, 45 30, 31, 32, 33, 34 – –
Buried in 72, 73 0 70, 71 – 70, 71 0 – –
ground
Embedded in 57, 58 3 1, 2, 59, 50, 51, 52, 44, 45 0 – –
structure 60 53
Surface – 20, 21, 4, 5 6, 7, 8, 9, 6, 7, 8, 30, 31, 32, 33, 34 36 –
mounted 22, 23 12, 13, 14 9
Overhead – – 0 10, 11 – 30, 31, 32, 33, 34 36 35
Immersed 80 80 0 – 0 0 – –
The number in each box indicates the item number in table 52-3.
– Not permitted.
0 Not applicable or not normally used in practice.

60364-5-52 © IEC:2001 – 9 –
Table 52-3 (52H) – Examples of methods of installation providing instructions for obtaining
current-carrying capacity
NOTE The illustrations are not intended to depict actual product or installation practices but are indicative of the
method described.
Reference method of
installation to be used to
Item
Methods of installation Description obtain current-carrying
No.
capacity
(see annex A)
Insulated conductors or single-core
Room
Room
1 cables in conduit in a thermally A1
a
insulated wall
Room Multi-core cables in conduit in a
Room
2 A2
a
thermally insulated wall
Room
Room Multi-core cable direct in a thermally
3 A1
a
insulated wall
Insulated conductors or single-core
cables in conduit on a wooden, or
4 B1
masonry wall or spaced less than

0,3 × conduit diameter from it
Multi-core cable in conduit on a
wooden, or masonry wall or spaced
5 B2
less than 0,3 × conduit diameter

from it
Insulated conductors or single-core
cables in cable trunking on a
wooden wall
B1
b
– run horizontally
b, c
– run vertically
6 7
Multi-core cable in cable trunking on
a wooden wall
d
Under consideration
b
– run horizontally
b, c
– run vertically
8 9
a 2
The inner skin of the wall has a thermal conductance of not less than 10 W/m ·K.
b
Values given for installation methods B1 and B2 in annex A are for a single circuit. Where there is more than
one circuit in the trunking the group reduction factor given in table A.52-17 is applicable, irrespective of the
presence of an internal barrier or partition.
c
Care shall be taken where the cable runs vertically and ventilation is restricted. The ambient temperature at
the top of the vertical section can be increased considerably. The matter is under consideration.
d
Values for reference method B2 may be used.

– 10 – 60364-5-52 © IEC:2001
Table 52-3 (continued)
Reference method of
installation to be used to
Item
Methods of installation Description obtain current-carrying
No.
capacity
(see annex A)
Insulated conductors or single-core B1
a
cable in suspended cable trunking
Multi-core cable in suspended cable
11 B2
a
trunking
10    11
Insulated conductors or single-core
12 A1
b
cable run in mouldings
Insulated conductors or single-core
B1
cables in skirting trunking
TV TV
ISDN ISDN
Multi-core cable in skirting trunking B2
13    14
Insulated conductors in conduit or
15 single-core or multi-core cable in A1
c
architrave
Insulated conductors in conduit or
16 single-core or multi-core cable in A1
c
window frames
Single-core or multi-core cables:
20 C
– fixed on, or spaced less than 0,3 ×
cable diameter from a wooden wall

C, with item 3 of
21 – fixed directly under a wooden ceiling
table A.52-17
22 – spaced from a ceiling Under consideration

a
Values given for installation methods B1 and B2 in annex A are for a single circuit. Where there is more than
one circuit in the trunking the group reduction factor given in table A.52-17 is applicable, irrespective of the
presence of an internal barrier or partition.
b
The thermal resistivity of the enclosure is assumed to be poor because of the material of construction and
possible air spaces. Where the construction is thermally equivalent to methods of installation 6 or 7, reference
method B1 may be used.
c
The thermal resistivity of the enclosure is assumed to be poor because of the material of construction and
possible air spaces. Where the construction is thermally equivalent to methods of installation 6, 7, 8, or 9,
reference methods B1 or B2 may be used.

60364-5-52 © IEC:2001 – 11 –
Table 52-3 (continued)
Reference method of
Item Methods of installation Description installation to be used to
No. obtain current-carrying
capacity
(see annex A)
> < > 0,3 D
e
≥0,3 D
e
c
30 C with item 2
On unperforated tray
a
of table A.52-17
> < ≥0,3 D
> 0,3 D e
e
> < > 0,3 D
e
≥0,3 D
e
c
31 E or F with item 4
On perforated tray
a, b
of table A.52-17
≥0,3 D
> < > 0,3 D e
e
> 0,3 D
> <
e
≥0,3 D
e
c
32 E or F
On brackets or on a wire mesh
> 0,3 D
≥0,3 De
> < e
33 Spaced more than 0,3 times E or F
cable diameter from a wall with item 4 or 5

of table A.52-17
a, b
or method G
34 On ladder E or F
35 Single-core or multi-core cable E or F
suspended from or incorporating

a support wire
36 Bare or insulated conductors on G
insulators
a
For certain applications it may be more appropriate to use specific factors, for example tables A.52-20 and
A.52-21 (see A.52.4.2 of annex A).
b
Care shall be taken where the cable runs vertically and ventilation is restricted. The ambient temperature at the
top of the vertical section can be increased considerably. The matter is under consideration.
c
D = the external diameter of a multi-core cable:
e
– 2,2 x the cable diameter when three single core cables are bound in trefoil, or
– 3 x the cable diameter when three single core cables are laid in flat formation.

– 12 – 60364-5-52 © IEC:2001
Table 52-3 (continued)
Item No. Methods of installation Description Reference method of
installation to be used to
obtain current-carrying
capacity
(see annex A)
40 Single-core or multi-core cable in a
1,5 D ≤ V < 20 D
e e
a, 2
building void
B2
V
V
D
D e
e
V ≥ 20 D
e
B1
Single-core or multi-core cable in conduit
d
in a building void
Under consideration
Insulated conductors in cable ducting
1,5 D ≤ V < 20 D
e e
a, c, d
in a building void
24 V
V B2
D
e
D
e
V ≥ 20 D
e
B1
Single-core or multi-core cable in cable Under consideration
d
ducting in a building void
VV
D
e
D
e
Insulated conductors in cable ducting in 1,5 D ≤ V < 5 D
e e
masonry having a thermal resistivity not
B2
a, b, d
V
V greater than 2 K·m/W
5 D ≤ V < 50 D
e e
B1
Single-core or multi-core cable in cable Under consideration
ducting in masonry having a thermal

d
resistivity not greater than 2 K·m/W
Single-core or multi-core cable:

1,5 D ≤ V < 5 D
e e
– in a ceiling void
V
B2
V a, b
– in a suspended floor
D
D
ee
5 D ≤ V < 50 D
e e
B1
Insulated conductors or single-core
B1
50 cable in flush cable trunking in the floor

Multi-core cable in flush cable trunking B2
51 in the floor
a
V = the smaller dimension or diameter of a masonry duct or void, or the vertical depth of a rectangular duct,
floor or ceiling void.
b
D = the external diameter of a multi-core cable:
e
– 2,2 × the cable diameter when three single core cables are bound in trefoil, or
– 3 × the cable diameter when three single core cables are laid in flat formation.
c
D = external diameter of conduit or vertical depth of cable ducting.
e
d
Care shall be taken where the cable runs vertically and ventilation is restricted. The ambient temperature at the
top of the vertical section can be increased considerably. The matter is under consideration.

60364-5-52 © IEC:2001 – 13 –
Table 52-3 (continued)
Reference method of
installation to be used to
Item
Methods of installation Description obtain current-carrying
No.
capacity
(see annex A)
Insulated conductors or single-core
TV TV B1
cables in embedded trunking
ISDN ISDN
Multi-core cable in embedded trunking B2
52        53
1,5 D ≤ V < 20 D
e e
Insulated conductors or single-core
V
V
cables in conduit in an unventilated
B2
D
D e
e
cable channel run horizontally or
V ≥ 20 D
e
a, b
vertically
B1
Insulated conductors in conduit in
55 an open or ventilated cable channel B1
c, d
in the floor
Sheathed single-core or multi-core
56 cable in an open or ventilated cable B1
d
channel run horizontally or vertically

Single-core or multi-core cable direct in
masonry having a thermal resistivity
not greater than 2 K·m/W
57 C
Without added mechanical
e, f
protection
Single-core or multi-core cable direct in
masonry having a thermal resistivity
58 C
not greater than 2 K·m/W
e, f
With added mechanical protection

a
De = external diameter of conduit
V = internal depth of the channel
The depth of the channel is more important than the width.
b
Care shall be taken where the cable runs vertically and ventilation is restricted. The ambient temperature at the
top of the vertical section can be increased considerably. The matter is under consideration.
c
For multi-core cable installed in method 55, use ratings for reference method B2.
d
It is recommended that these methods of installation are used only in areas where access is restricted to
authorised persons so that the reduction in current carrying capacity and the fire hazard due to the accumulation
of debris can be prevented.
e 2
For cables having conductors not greater than 16 mm , the current-carrying capacity may be higher.
f
Thermal resistivity of masonry is not greater than 2 K·m/W.

– 14 – 60364-5-52 © IEC:2001
Table 52-3 (continued)
Reference method of
installation to be used to
Item
Methods of installation Description obtain current-carrying
No.
capacity
(see annex A)
Insulated conductors or single-core
59 B1
a
Cables in conduit in masonry
a
60 Multi-core cables in conduit in masonry B2

Multi-core cable in conduit or in cable
70 D
ducting in the ground
Single-core cable in conduit or in cable
71 D
ducting in the ground
Sheathed single-core or multi-core cables
D
direct in the ground
– without added mechanical protection
(see note)
Sheathed single-core or multi-core cables
73 D
direct in the ground
– with added mechanical protection
(see note)
Sheathed single-core or multi-core cables
80 Under consideration
immersed in water
NOTE  The inclusion of directly buried cables in this item is satisfactory when the soil thermal resistivity is of
the order of 2,5 K·m/W. For lower soil resistivities, the current-carrying capacity for directly buried cables is
appreciably higher than for cables in ducts.
a
Thermal resistivity of masonry is not greater than 2 K·m/W.

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521.6 Conduits and trunking systems
Several circuits are allowed in the same conduit or trunking provided all conductors are
insulated for the highest nominal voltage present.
522 Selection and erection of wiring systems in relation to external influences
NOTE The external influences categorized in table 51A of IEC 60364-5-51 which are of significance to wiring
systems are included in this clause.
522.1 Ambient temperature (AA)
522.1.1  Wiring systems shall be selected and erected so as to be suitable for the highest
local ambient temperature and to ensure that the limiting temperature indicated in table 54-4
will not be exceeded.
522.1.2  Wiring system components including cables and wiring accessories shall only be
installed or handled at temperatures within the limits stated in the relevant product
specification or as given by the manufacturers.
522.2 External heat sources
522.2.1 In order to avoid the effects of heat from external sources, one of the following
methods or an equally effective method shall be used to protect wiring systems:
– shielding;
– placing sufficiently far from the source of heat;
– selecting a system with due regard for the additional temperature rise which may occur;
– local reinforcement or substitution of insulating material.
NOTE Heat from external sources may be radiated, convected or conducted, e.g.
– from hot water systems,
– from plant appliances and luminaires,
– from manufacturing process,
– through heat conducting materials,
– from solar gain of the wiring system or its surrounding medium.
522.3 Presence of water (AD)
522.3.1 Wiring systems shall be selected and erected so that no damage is caused by the
ingress of water. The completed wiring system shall comply with the IP degree of protection
relevant to the particular location.
NOTE In general, the sheaths and insulation of cables for fixed installations may be regarded, when intact, as
proof against penetration by moisture. Special considerations apply to cables liable to frequent splashing,
immersion or submersion.
522.3.2 Where water may collect or condensation may form in wiring systems, provision shall
be made for its escape.
522.3.3 Where wiring systems may be subjected to waves (AD6), protection against mecha-
nical damage shall be afforded by one or more of the methods of 522.6, 522.7 and 522.8.

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522.4 Presence of solid foreign bodies (AE)
522.4.1 Wiring systems shall be selected and erected so as to minimize the danger arising
from the ingress of solid foreign bodies. The completed wiring system shall comply with the IP
degree of protection relevant to the particular location.
522.4.2 In a location where dust in significant quantity is present (AE4), additional precautions
shall be taken to prevent the accumulation of dust or other substances in quantities which
could adversely affect the heat dissipation from the wiring system.
NOTE A wiring system which facilitates the removal of dust may be necessary (see clause 529).
522.5 Presence of corrosive or polluting substances (AF)
522.5.1 Where the presence of corrosive or polluting substances, including water, is likely to
give rise to corrosion or deterioration, parts of the wiring system likely to be affected shall be
suitably protected or manufactured from a material resistant to such substances.
NOTE Suitable protection for application during erection may include protective tapes, paints or grease.
522.5.2 Dissimilar metals liable to initiate electrolytic action shall not be placed in contact with
each other, unless special arrangements are made to avoid the consequences of such
contacts.
522.5.3 Materials liable to cause mutual or individual deterioration or hazardous degradation
shall not be placed in contact with each other.
522.6 Impact (AG)
522.6.1 Wiring systems shall be selected and erected so as to minimize the damage arising
from mechanical stress, e.g. by impact, penetration or compression.
522.6.2 In fixed installations where impacts of medium severity (AG2) or high severity (AG3)
can occur protection shall be afforded by:
– the mechanical characteristics of the wiring system; or
– the location selected; or
– the provision of additional local or general mechanical protection; or
– by any combination of the above.
522.7 Vibration (AH)
522.7.1  Wiring systems supported by or fixed to structures of equipment subject to vibration
of medium severity (AH2) or high severity (AH3) shall be suitable for such conditions,
particularly where cables and cable connections are concerned.
NOTE Special attention should be paid to connections to vibrating equipment. Local measures may be adopted
such as flexible wiring systems.
522.7.2  Fixed installation of suspended current-using equipment, e.g. luminaires, shall be
connected by cable with flexible core. Where no vibration nor movement can be expected,
cable with non-flexible core may be used
522.8 Other mechanical stresses (AJ)
522.8.1  Wiring systems shall be selected and erected so as to prevent during installation,
use or maintenance, damage to the sheath and insulation of cables and insulated conductors
and their terminations.
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522.8.2  (522.8.1.1) When buried in the structure, conduits or cable ducting systems shall be
completely erected for each circuit before any insulated conductor or cable is drawn in.
522.8.3  (522.8.1.2) The radius of every bend in a wiring system shall be such that
conductors or cables shall not suffer damage.
522.8.4  (522.8.1.3) Where the conductors or cables are not supported continuously due to
the method of the installation, they shall be supported by suitable means at appropriate
intervals in such a manner that the conductors or cables do not suffer damage by their own
weight.
522.8.5  (522.8.1.4) Where a permanent tensile stress is applied to the wiring system (e.g.
by its own weight in vertical runs) a suitable type of cable or conductor with appropriate cross-
sectional areas and method of mounting shall be selected in such a manner that the
conductors or cables do not suffer damage by their own weight.
522.8.6  (522.8.1.5) Wiring systems intended for the drawing in or out of conductors or
cables shall have adequate means of access to allow this operation.
522.8.7  (522.8.1.6) Wiring systems buried in floors shall be sufficiently protected to prevent
damage caused by the intended use of the floor.
522.8.8  (522.8.1.7) Wiring systems which are rigidly fixed and buried in the walls shall be
run horizontally or vertically or parallel to the room edges.
Wiring systems concealed in the structure but not fixed may follow the shortest practical
route.
522.8.9  (522.8.1.8) Flexible wiring systems shall be installed so that excessive tensile
stress to the conductors and connections is avoided.
522.9 Presence of flora and/or mould growth (AK)
522.9.1  Where the conditions experienced or expected constitute a hazard (AK2), the wiring
system shall be selected accordingly or special protective measures shall be adopted.
NOTE An installation method which facilitates the removal of such growths may be necessary (see clause 529).
522.10  Presence of fauna (AL)
522.10.1  Where conditions experienced or expected constitute a hazard (AL2) the wiring
system shall be selected accordingly or special protective measures shall be adopted,
for example, by:
– the mechanical characteristics of the wiring system; or
– the location selected; or
– the provision of additional local or general mechanical protection; or
– by any combination of the above.
522.11  Solar radiation (AN)
522.11.1  Where significant solar radiation (AN2) is experienced or expected, a wiring system
suitable for the conditions shall be selected and erected or adequate shielding shall be
provided.
NOTE See also 522.2.1 dealing with temperature rise.

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522.12  Seismic effects (AP)
522.12.1  The wiring system shall be selected and erected with due regard to the seismic
hazards of the location of the installation.
522.12.2  Where the seismic hazards experienced are low severity (AP2) or higher, particular
attention shall be paid to the following:
– the fixing of wiring systems to the building structure;
– the connections between the fixed wiring and all items of essential equipment, e.g. safety
services, shall be selected for their flexible quality.
522.13  Wind (AR)
522.13.1  See 522.7, Vibration (AH), and 522.8, Other mechanical stresses (AJ).
522.14  Nature of processed or stored materials (BE)
522.14.1  See 527, Selection and erection of wiring systems to minimize the spread of fire.
522.15  (522.14) Building design (CB)
522.15.1 (522.14.1) Where risks due to structural movement exist (CB3), the cable support
and protection system employed shall be capable of permitting relative movement so that
conductors and cables are not subjected to excessive mechanical stress.
522.15.2  (522.14.2) For flexible or unstable structures (CB4), flexible wiring systems shall
be used.
523 Current-carrying capacities
523.1  (523.1.3) The current to be carried by any conductor for sustained periods during
normal operation shall be such that the appropriate temperature limit specified in table 52-4 is
not exceeded. The value of current shall be selected in accordance with 523.2, or determined
in accordance with 523.3.
Table 52-4 (52-A) – Maximum operating temperatures for types of insulation
a
Type of insulation
Temperature limit
°C
Polyvinyl-chloride (PVC)  70 at the conductor
b
Cross-linked polyethylene (XLPE) and ethylene propylene rubber (EPR)
90 at the conductor
Mineral (PVC covered or bare exposed to touch)  70 at the sheath
b, c
Mineral (bare not exposed to touch and not in contact with combustible material)
105 at the sheath
a
The maximum permissible conductor temperatures given in table 52-4 on which the tabulated current-carrying
a
capacities given in annex A are based, have been taken from IEC 60502 (1983) and IEC 60702 (1981) and
are shown on these tables.
b
Where a conductor operates at a temperature exceeding 70 °C it shall be ascertained that the equipment
connected t
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