IEC 60670-1:2002

IEC 60670-1 ®
Edition 1.1 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Boxes and enclosures for electrical accessories for household and similar fixed
electrical installations –
Part 1: General requirements
Boîtes et enveloppes pour appareillage électrique pour installations électriques
fixes pour usages domestiques et analogues –
Partie 1: Règles générales
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IEC 60670-1 ®
Edition 1.1 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Boxes and enclosures for electrical accessories for household and similar fixed
electrical installations –
Part 1: General requirements
Boîtes et enveloppes pour appareillage électrique pour installations électriques
fixes pour usages domestiques et analogues –
Partie 1: Règles générales
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX CS
ICS 29.120.10 ISBN 978-2-88912-514-2

– 2 – 60670-1  IEC:2002+A1:2011
CONTENTS
FOREWORD . 4

1 Scope . 6
2 Normative references . 6
3 Definitions . 7
4 General requirements . 9
5 General notes on tests . 9
6 Ratings . 9
7 Classification . 10
8 Marking . 11
9 Dimensions . 12
10 Protection against electric shock . 12
11 Provision for earthing . 13
12 Construction . 16
13 Resistance to ageing, protection against ingress of solid objects and against
harmful ingress of water . 30
14 Insulation resistance and electric strength . 35
15 Mechanical strength . 37
16 Resistance to heat . 41
17 Creepage distances, clearances and distances through sealing compound . 44
18 Resistance of insulating material to abnormal heat and fire . 44
19 Resistance to tracking . 45
20 Resistance to corrosion . 45
21 Electromagnetic compatibility (EMC) . 46

Annex A (informative) Examples of enclosures and parts thereof . 69

Bibliography . 70

Figure 1 – Examples of membranes and grommets . 47
Figure 2 – Earthing strap (see 11.2) . 48
Figure 3 – Test strap (see 11.2) . 49
Figure 4 – Volume measurement (see 12.12.5 12.15) . 49
Figure 5 – Test wall in accordance (see 13.3.2) . 50
Figure 6 – Reference surfaces for boxes and enclosures . 51
Figure 7 – Mounting block for flush-type equipment boxes and enclosures
in order to apply blows on the rear surface (see 15.3) . 52
Figure 8 – Apparatus for impact test at low temperature (see 15.1) . 53
Figure 9 – Application points for blows for part A (see 15.3) Height of fall for blows for
part A (see 15.3) . 54
Figure 10 – Sequence of blows for parts A, B, C, D, E, F and G (see 15.3) . 56
Figure 11 – Apparatus for testing the cable anchorage (see 12.6) . 57

60670-1  IEC:2002+A1:2011 – 3 –
Figure 12 – Arrangement for test on covers or cover-plates (see 12.1.2.2) . 58
Figure 13 – Gauge (thickness about 2 mm) for the verification of the outline of lids,
covers or cover-plates (see 12.1.2.3) . 58
Figure 14 – Examples of application of the gauge of Figure 13 on covers fixed without
screws on a mounting surface or supporting surface (see 12.1.2.3) . 59
Figure 15 – Examples of application of the gauge of Figure 13 (see 12.1.2.3) . 60
Figure 16 – Gauge for verification of grooves, holes and reverse tapers (see 12.1.2.4) . 61
Figure 17 – Sketch showing the direction of application of the gauge of Figure 16
(see 12.1.2.4) . 61
Figure 18 – Verification of fixing means for boxes and enclosures classified according
to 7.7.1 (see 12.11) . 62
Figure 19 – Test according to to 12.14.3 12.12.3 . 63
Figure 20 – Rigid crossbar (see 16.3) . 64
Figure 21 – Diagrammatic representation of the glow-wire test (see Clause 18) . 64
Figure 22 – Example of mounting block for boxes to be embedded in masonry (flush
type and semi-flush type) according to 12.10 . 65
Figure 23 – Example of the fixing of the auxiliary device mounted on a specimen
according to 12.10 . 66
Figure 24 – Example of test apparatus for the test according to 12.10 . 67
Figure 25 – Example of the protected volume (see 13.3.4) . 68
Figure 26 – Demonstration of the non-penetration of the internal volume . 68
Figure A.1 – Examples of enclosures and parts of thereof . 69

Table 1 – Classification of boxes and enclosures . 10
Table 2 – Forces to be applied to covers, cover-plates or actuating members whose
fixing is not dependent on screws . 17
Table 3 – Forces and torques to be applied to cable anchorages . 20
Table 4 – Tightening torques for the verification of the mechanical strength of screws . 24
Table 5 – Torque test values for cable glands . 29
Table 6 – Test voltage for electric strength test . 37
Table 7 – Determination of parts A, B, C, D E, F and G. 40
Table 8 – Height of fall for impact test . 40

– 4 – 60670-1  IEC:2002+A1:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
BOXES AND ENCLOSURES FOR ELECTRICAL ACCESSORIES
FOR HOUSEHOLD AND SIMILAR FIXED ELECTRICAL INSTALLATIONS –

Part 1: General requirements
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

This consolidated version of IEC 60670-1 consists of the first edition (2002) [documents
23B/681/FDIS and 23B/693/RVD], its amendment 1 (2011) [documents 23B/981/FDIS and
23B/991/RVD] and its corrigendum of February 2003. It bears the edition number 1.1.
The technical content is therefore identical to the base edition and its amendment and
has been prepared for user convenience. A vertical line in the margin shows where the
base publication has been modified by amendment 1. Additions and deletions are
displayed in red, with deletions being struck through.

60670-1  IEC:2002+A1:2011 – 5 –
International Standard IEC 60670-1 has been prepared by subcommittee 23B: Plugs, socket-
outlets and switches, of IEC technical committee 23: Electrical accessories.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this publication, the following print types are used:
− requirements proper: in roman type
− test specifications: in italic type
− notes: in smaller roman type.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

– 6 – 60670-1  IEC:2002+A1:2011
BOXES AND ENCLOSURES FOR ELECTRICAL ACCESSORIES
FOR HOUSEHOLD AND SIMILAR FIXED ELECTRICAL INSTALLATIONS –

Part 1: General requirements
1 Scope
This part of IEC 60670 applies to boxes, enclosures and parts of enclosures (hereafter called
“boxes” and “enclosures”) for electrical accessories with a rated voltage not exceeding
1 000 V a.c. and 1 500 V d.c. intended for household or similar fixed electrical installations,
either indoors or outdoors.
NOTE Requirements for particular types of boxes and enclosures are given in the relevant parts 2 of IEC 60670.
Boxes and enclosures complying with this standard are suitable for use at ambient tem-
perature not normally exceeding 25 °C but occasionally reaching 35 °C.
This International Standard is intended to apply to boxes and enclosures for electrical
accessories within the scope of IEC technical committee 23.
NOTE This standard may also be used as a reference document for other IEC technical committees and
subcommittees.
A box or an enclosure which is an integral part of an electrical accessory and provides
protection for that accessory against external influences (for example mechanical impact,
ingress of solid objects or water, etc.) is covered by the relevant standard for such an
accessory.
This standard does not apply to
– ceiling roses;
– luminaire supporting couplers;
– boxes, enclosures and parts of enclosures specifically designed to be used for cable
trunking and ducting systems complying with IEC 61084 and which are not intended to be
installed outside of these systems.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60068-2-75:1997, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 60112:1979, Method for determining the comparative and the proof-tracking indices of
solid insulating materials under moist conditions
IEC 60423:1993, Conduits for electrical purposes – Outside diameters of conduits for
electrical installations and threads for conduits and fittings
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60695-2-11:2000, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods -
Glow-wire flammability test method for end-products

60670-1  IEC:2002+A1:2011 – 7 –
IEC 60695-10-2:1995, Fire hazard testing – Part 10-2: Guidance and test methods for the
minimization of the effects of abnormal heat on electrotechnical products involved in fires –
Method for testing products made from non-metallic materials for resistance to heat using the
ball pressure test
IEC 60981:1989, Extra-heavy duty rigid steel conduits for electrical installations
IEC 61032:1997, Protection of persons and equipment by enclosures – Probes for verification
IEC 61084 (all parts), Cable trunking and ducting systems for electrical installations
IEC 61140:2001, Protection against electric shock – Common aspects for installation and
equipment
IEC 62444:2010, Cable glands for electrical installations
3 Definitions
For the purposes of this part of IEC 60670, the following definitions apply.
3.1
enclosure
combination of parts, such as boxes, covers, cover-plates, lids, box extensions, accessories,
etc., providing after assembly and installation as in normal use, an appropriate protection
against external influences, and a defined protection against contact with enclosed live parts
from any accessible direction (see Annex A)
3.2
box
part of an enclosure provided with means for fixing a cover, cover-plate, accessory, etc., and
intended to receive accessories (such as socket-outlets, switches, etc.)
3.3
box extension
part of an enclosure which is intended to extend a box for the purpose of either increasing the
internal volume of the box or enclosure or to adjust for mounting the box flush or semi-flush
with the finished surface of a wall or the like
3.4
lid, cover or cover-plate
part of an enclosure, not integral with or part of an accessory, which may either retain an
accessory in position or enclose it
3.5
raised cover
cover intended for mounting directly onto a box to provide for the attachment of accessories
and to increase the internal volume of the enclosure
NOTE The centre portion of the cover is raised to accommodate a specific wall or ceiling thickness and to permit
the mounting of the accessory on it, flush with the surface of the wall or ceiling.
3.6
exposed conductive part
conductive part of electrical equipment, which can be touched and which is not normally live,
but which can become live when basic insulation fails
3.7
surface mounting box or enclosure
box or enclosure which is intended for mounting on a surface (see Annex A)

– 8 – 60670-1  IEC:2002+A1:2011
3.8
flush-mounting box or enclosure
box or enclosure which is intended for mounting flush with the surface (see Annex A)
3.9
semi-flush mounting box or enclosure
box or enclosure which is intended to fit within a mounting surface and partially projects from
the mounting surface
3.10
cable gland
device designed to permit the entry of a cable into an enclosure and which provides sealing
and retention. It may also provide other functions such as earthing, bonding, insulation, cable
guarding, strain relief or a combination of these
a device designed to permit the entry of a cable, flexible cable or insulated conductor into an
enclosure, and which provides sealing and retention. It may also provide other functions such
as earthing, bonding, insulation, cable guarding, strain relief or a combination of these
3.11
seal (packing)
material used to fill up the space between the inside of a gland and the cable passing
through, usually compressed by the gland and thereby forming a joint
3.12
gasket
material introduced between mating surfaces of an enclosure which in compression forms a
joint
3.13
grommet
component used to support and protect the cable or conduit at the point of entry. It may also
prevent the ingress of moisture or contaminants (see Figure 1)
3.14
entry membrane
component or an integral part of an enclosure used to protect the cable which may be used to
support the cable or conduit at the point of entry
NOTE An entry membrane may also prevent the ingress of moisture or contaminants and may be part of a grommet (see
Figure 1).
3.15
protecting membrane
component or an integral part of an enclosure that is not intended to be penetrated in normal
use and is intended to provide protection against ingress of water or solid objects and/or to
allow the operation of an accessory (see Figure 1).
3.16
composite material
combination of metal and insulating material
3.17
spout (hub)
open entry of a box permitting the insertion and containment of a conduit
3.18
cable retention
ability to limit the displacement of a fitted cable against pull forces

60670-1  IEC:2002+A1:2011 – 9 –
3.19
cable anchorage
ability to limit the displacement of a fitted flexible cable against pull and push forces and
torques
3.20
blanking-plug
a blanking-plug is a component used to close an open inlet or an open knock out
4 General requirements
Each part of the enclosure shall be so designed and constructed that, when mounted and
installed as for normal use, the enclosure ensures adequate electrical and mechanical
protection to the parts so enclosed and minimizes the risk of danger to the user or
surroundings.
Compliance is checked by carrying out the relevant tests specified.
5 General notes on tests
5.1 Tests according to this standard are type tests.
Unless otherwise specified boxes and enclosures are tested as delivered.
Accessories complying with other standards are not tested.
Tests on boxes and enclosures of insulating material shall be performed after a precondi-
tioning of at least 10 days at ambient temperature and relative air humidity of between 45 %
and 85 %.
Unless otherwise specified the tests shall be carried out in the order of the clauses at an
ambient temperature of (20 ± 5) °C on a set of three new specimens.
5.2 If one of the specimens does not satisfy a test due to an assembly or a manufacturing
fault, that test and any preceding ones which may have influenced the results of the test shall
be repeated and also the tests which follow shall be made in the required sequence on
another full set of specimens, all of which shall comply with the requirements.
NOTE When submitting the first set of specimens, the applicant may also submit the additional set of specimens
which may be necessary, should one specimen fail. The testing station will then, without further request, test the
additional set of specimens and will only reject if a further failure occurs. If the additional set of specimens is not
submitted at the same time, the failure of one specimen will entail rejection.
6 Ratings
See relevant parts 2 of this standard.

– 10 – 60670-1  IEC:2002+A1:2011
7 Classification
Boxes and enclosures are classified according to Table 1.
Table 1 – Classification of boxes and enclosures
Classification criteria
7.1 The nature of their material 7.1.1 Insulating
7.1.2 Metallic
7.1.3 Composite
a
7.2.1 Flush, semi-flush or 7.2.1.1 Non-combustible walls,
7.2 The method of installation
embedded in non-combustible ceilings or non-
combustible floors
7.2.1.2 Combustible walls,
combustible ceilings or combustible
floors
7.2.1.3 Hollow walls, hollow
ceilings, hollow floors or furniture
7.2.2 Surface mounting on 7.2.2.1 Non-combustible walls,
non-combustible ceilings, non-
combustible floors or
non-combustible furniture
7.2.2.2 Combustible walls,
combustible ceilings, combustible
floors or combustible furniture
7.2.3 Placement 7.2.3.1 Suitable for installation into
concrete during the casting process
(see 7.6)
7.2.3.2 Suitable for all types of
installation except into concrete
b
7.3 The type(s) of inlets (outlets) 7.3.1 With inlets for sheathed
cables for fixed installations
7.3.2 With inlets for flexible cables
7.3.3 With inlets for plain or
corrugated conduits
7.3.4 With inlets for threaded
conduits
7.3.5 With inlets for other types of
conductors/cables or conduits
7.3.6 With spouts (hub)
7.3.7 Without inlets. Inlet openings
will be made during installation
7.4 The clamping means 7.4.1 With cable retention
7.4.2 With cable anchorage
7.4.3 With clamping means for
flexible conduit
7.4.4 Without clamping means
7.5 The minimum and maximum 7.5.1 –5 °C to +60 °C
temperatures during installation
7.5.2 –15 °C to +60 °C
7.5.3 –25 °C to +60 °C
7.6 The maximum temperature 7.6.1 +60 °C
c
during the casting process
d
7.6.2 +90 °C
60670-1 © IEC:2002+A1:2011 – 11 –
Table 1 (continued)
Classification criteria
7.7 Boxes and enclosures for 7.7.1 Class Ha
hollow walls and the like according

7.7.2 Class Hb 7.7.2.1 Class Hb for walls
to 7.2.1.3 are classified as
7.7.2.2 Class Hb for ceilings
7.7.3 According to the degree of 7.7.3.1 IP2X
protection of the part mounted in the
hollow wall
7.7.3.2 >IP2X
7.8 The provision for fixing 7.8.1 Boxes supplied with screws
accessories to boxes
7.8.2 Boxes intended to receive
screws
7.8.3 Boxes intended to receive
claws
7.8.4 Boxes intended to receive
other means
a
Boxes and enclosures may be suitable for more than one method of installation.
b
Boxes and enclosures may have more than one type of inlet.
c
These apply only to boxes and enclosures classified according to 7.2.3.1.
d
These types are for use in concrete and will temporarily withstand temperatures up to +90 °C during the casting
process.
8 Marking
8.1 Boxes and enclosures shall be marked with
a) the name, trade mark or identification mark of the manufacturer or the responsible vendor.
In addition enclosures shall be marked with
b) the IP code against ingress of solid objects if higher than IP2X in which case the second
IP numeral shall also be marked;
c) the IP code against harmful ingress of water if higher than IPX0 in which case the first IP
numeral shall also be marked.
IPXX
d) the following marking     on cover of flush enclosures intended to be mounted on rough
surfaces and where the IP is dependent on the surface (see Figure 5).
The IP code, if applicable, shall be marked on the outside of the enclosure so as to be easily
discernible when the enclosure is mounted and wired as for normal use.
e) the type reference, which may be a catalogue number;
NOTE In the following country the marking of the type reference is not used: UK.
The following information shall be marked on the boxes and enclosures or provided by the
manufacturer on the smallest package unit or in the instructions of the manufacturer:
f) the maximum temperature during the building process if 90 °C;
g) the necessary information concerning the openings which can be made during installation
in the case of boxes and enclosures classified according to 7.3.7;
h) the minimum temperature during installation for boxes classified according to 7.5.2
and 7.5.3;
– 12 – 60670-1  IEC:2002+A1:2011
i) for boxes and enclosures classified as in 7.7.2, the minimum internal volume in cm as
determined by the test in 12.15 2.5. The internal volume shall be marked on the inside of
the box or enclosure. The marking on a box or enclosure shall be such that the value can
be read after installation of the box in the normal manner but before the installation of the
wiring devices and wiring;
j) the symbol Ha for boxes classified according to 7.7.1 and the symbol Hb for boxes
classified according to 7.7.2.
Unless self-evident, further information for the correct use of the enclosure shall be given in
the manufacturer's catalogue or in an instruction sheet.
In special cases, in order to achieve a higher degree of protection by the use of special parts
an instruction sheet should be provided and should indicate the higher degree of protection.
In such a case, the marking covers the initial degree of protection.
8.2 The marking on the boxes and enclosures shall be durable and easily legible.
Compliance with 8.1 and 8.2 is checked by inspection and by the following test.
The test is made by rubbing the marking by hand for 15 s with a piece of cloth soaked with
water and again for 15 s with a piece of cloth soaked with petroleum spirit.
NOTE 1 Marking made by impression, moulding, pressing or engraving is considered durable and is therefore not
subjected to this test.
NOTE 2 It is recommended that the petroleum spirit used consist of a solvent hexane with an aromatic content of
maximum 0,1 % by volume, a kauributanol value of approximately 29, an initial boiling-point of approximately
65 °C, a dry point of approximately 69 °C and a density of approximately 0,68 g/cm³.
After the test the marking shall still be legible.
9 Dimensions
Boxes and enclosures shall comply with the appropriate standard sheets, if any.
Compliance is checked by inspection and measurement.
10 Protection against electric shock
Boxes and enclosures shall be so designed that, when they are assembled, equipped and
installed as for normal use in accordance with the manufacturer's instructions, the live parts
are not accessible.
Enclosures shall have a degree of protection of at least IPXXB, when assembled, equipped
and installed as for normal use.
Where enclosures are supplied without a cover, cover-plate or an accessory they are tested
with the appropriate parts fitted according to the information given in the manufacturer's
instructions.
Compliance is checked by inspection and in case of doubt by the following test.
Enclosures shall be tested with test probe 11 according to IEC 61032 applied for 1 min with a
force of 20 N, and the test probe shall not enter that part of the enclosure where live parts are
to be installed according to the manufacturer's instructions.
Tests shall be carried out on parts which are accessible after installation.

60670-1  IEC:2002+A1:2011 – 13 –
In addition, all enclosures according to 7.1.1 and 7.1.3 with parts of thermoplastic or
elastomeric material shall be subjected for 1 min to a force applied through the tip of test
probe 11 of IEC 61032 but at an ambient temperature of (35 ± 2) °C, the enclosure being at
this temperature.
The probe is applied to
– all places except membranes or the like, where yielding of insulating material could impair
the safety, with a force of 75 N;
– knock-outs with a force of 10 N.
Boxes and enclosures shall be so designed that, when they are assembled, equipped and
installed as for normal use in accordance with the manufacturer's instructions, live parts are
not accessible.
Where enclosures are supplied without a cover, cover-plate or an accessory they are tested
with the appropriate parts fitted according to the information given in the manufacturer's
instructions.
Compliance is checked by inspection and in case of doubt by the following test.
Enclosures shall be tested with test probe 11 according to IEC 61032 applied for 1 min with a
force of 20 N, and the test probe shall not penetrate in the internal volume of the enclosure,
as shown in Figure 26.
Tests shall be carried out on parts which are accessible after installation.
In addition, all enclosures according to 7.1.1 and 7.1.3 with parts made of thermoplastic or
elastomeric material shall be subjected for 1 min to a force applied through the tip of test
probe 11 of IEC 61032 but at an ambient temperature of (35 ± 2) °C, the enclosure being at
this temperature.
The probe is applied to all places except membranes or the like, where yielding of insulating
material could impair the safety, with a force of 75 N.
11 Provision for earthing
11.1 Boxes and enclosures with exposed conductive parts
Boxes and enclosures with exposed conductive parts shall be provided with an earthing
means of low resistance or have provision for the fitting of such an earthing means. For the
purpose of this requirement, small screws and the like, for fixing bases, covers or cover-
plates, etc. isolated from live parts, are not considered as exposed conductive parts.
Exposed conductive parts of covers or cover-plates shall be connected through a low-
resistance connection to the earthing means when fitted as for normal use.
Compliance is checked by inspection and the following test.
A current derived from an a.c. source having a no-load voltage not exceeding 12 V and equal
to (25 ± 1) A is passed between the earthing terminal and each exposed conductive part in
turn. The voltage drop between the earthing terminal and each of the exposed conductive
parts is measured, and the resistance calculated from the current and this voltage drop.
In no case shall the resistance exceed 0,05 Ω.
NOTE 1 Care should be taken that the contact resistance between the tip of the measuring probe and the
exposed conductive part under test does not influence the test results.

– 14 – 60670-1  IEC:2002+A1:2011
NOTE 2 In insulating boxes and enclosures having an IP > X0, provisions can be made for the addition of means
for the effective continuity of the earthing conductor, when more than one inlet is provided.
Boxes and enclosures with exposed conductive parts shall be provided with an earthing
means of low resistance or have provision for the fitting of such an earthing means. For the
purpose of this requirement, small screws and the like, for fixing bases, covers or coverplates,
etc. isolated from live parts, are not considered as exposed conductive parts.
The earthing means or the provision for the fitting of such an earthing means shall be located
so that:
– the means is readily accessible through the open face of the box, and
– the removal of an accessory mounted in the box does not disturb the continuity of the
earthing circuit, and
– the means is not part of a removable cover, back, or side of the box or enclosure.
Compliance is checked by inspection.
Exposed conductive parts of covers or cover-plates shall be connected through a low
resistance connection to the earthing means when fitted as for normal use.
Compliance is checked by the following test.
A current derived from an a.c. source having a no-load voltage not exceeding 12 V and equal
to (25 ± 1) A is passed between the earthing terminal and each exposed conductive part in
turn. The voltage drop between the earthing terminal and each of the exposed conductive
parts is measured, and the resistance calculated from the current and this voltage drop.
In no case shall the resistance exceed 0,05 Ω.
NOTE 1 Care should be taken that the contact resistance between the tip of the measuring probe and the
exposed conductive part under test does not influence the test results.
NOTE 2 In insulating boxes and enclosures having an IP degree higher than IPX0, provisions can be made for the
addition of means for the effective continuity of the earthing conductor, when more than one inlet is provided.
11.2 Boxes and enclosures of insulating material classified according to 7.7.2
Boxes and enclosures of insulating material shall be provided with a minimum of one earthing
strap having one screw terminal for earthing purposes with a connecting capacity of at least
4 mm . The design of the earthing strap shall ensure that the metal mounting yokes of
accessories mounted inside the box and metallic covers mounted on the box are connected to
the earthing conductors (see Figure 2).
Compliance is checked by the following test.
The test shall be conducted on one specimen in the condition as delivered and on one
specimen after it has been conditioned in an air-circulating oven for 168 h at 90 °C and then
cooled to room temperature.
The test strap shown in Figure 3 shall be attached to the earthing strap by placing the slotted
end under the earthing terminal screw. The threads of the earthing terminal shall not be
stripped when the torque shown in the relevant column of Table 4 is applied.
For testing of the conditioned sample the test strap shall be attached prior to the conditioning.
With the specimen secured, a force of 45 N shall be applied to the test strap for 5 min in the
direction perpendicular to the open face of the specimen.

60670-1  IEC:2002+A1:2011 – 15 –
The force shall be applied without jerks. If a tensile machine is used, a jaw separation speed
of 10mm/min shall be applied.
After each test the test strap shall not have become loose or detached from the specimen.
Boxes and enclosures of insulating material shall be provided with a minimum of one earthing
strap having one screw terminal for earthing purposes with a connecting capacity of at least
4 mm . The design of the earthing strap shall ensure that the metal mounting yokes of
accessories mounted inside the box and metallic covers mounted on the box are connected to
the earthing conductors (see Figure 2).
Compliance is checked by inspection.
The earthing strap shall be securely fastened to the box or enclosure.
Compliance is checked by the test in 16.3.2.
11.3 Boxes or enclosures with removable sides according to 7.1.2
A box or enclosure classified according to 7.1.2 that has removable sides shall be constructed
so that the electrical bond between separable parts includes at least one threaded screw
connection.
Compliance is checked by inspection.
11.4 Earthing terminal threads
The threads of the earthing terminal delivered with or integrated in boxes and enclosures shall
not be stripped when the torque shown in the relevant column of Table 4 is applied.
Compliance is checked by inspection and by the following test.
The screws are tightened and loosened 5 times.
The test is made by using a suitable screwdriver or an appropriate tool applying a torque as
indicated in Table 4.
If a screw has a hexagonal head with a slot, only the test with the screwdriver is made, with
the relevant torque given in column II of Table 4.
Greater values of torque may be used if so stated by the manufacturer, when the relevant
information is provided.
Column I applies to screws which cannot be tightened by means of a screwdriver with a blade
wider than the nominal diameter of the thread of the screw.
Column II applies to other screws which are tightened by means of a screwdriver.
Column III applies to screws and nuts which are tightened by means other than a screwdriver.
Column IV applies to screws which are tightened by means of a square blade screwdriver.
During the test, there shall be no damage, such as breakage of screw or damage to the head
slot (rendering the use of the appropriate screwdriver impossible) or to the threads or to the
enclosure impairing the further use of the fixing means. The screws shall not be tightened in
jerks.
– 16 – 60670-1  IEC:2002+A1:2011
12 Construction
Box
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