IEC 60423:2007

IEC 60423
Edition 3.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Conduit systems for cable management – Outside diameters of conduits for
electrical installations and threads for conduits and fittings

Systèmes de conduits pour la gestion du câblage – Diamètres extérieurs des
conduits pour installations électriques et filetages pour conduits et accessoires
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IEC 60423
Edition 3.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Conduit systems for cable management – Outside diameters of conduits for
electrical installations and threads for conduits and fittings

Systèmes de conduits pour la gestion du câblage – Diamètres extérieurs des
conduits pour installations électriques et filetages pour conduits et accessoires

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
M
CODE PRIX
ICS 29.120.10 ISBN 2-8318-9268-6

– 2 – 60423 © IEC:2007
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references.6
3 Outside diameters and threads .6
4 Gauges.6
5 Samples of conduit .7

Bibliography .13

Figure 1 – Basic profile of screw threads .9
Figure 2 – Gauges for checking maximum outside diameters of threadable conduits.10
Figure 3a – Gauges for checking minimum outside diameters of rigid metallic
threadable conduits.11
Figure 3b – Gauges for checking minimum outside diameters of threadable conduits
other than rigid metallic .12
Figure 3 – Gauges for checking minimum outside diameters of threadable conduits.12

Table 1 – Outside diameters for threadable conduits and thread details for conduits and
associated fittings .8
Table 2 – Outside diameters for non-threadable conduit .9

60423 © IEC:2007 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
CONDUIT SYSTEMS FOR CABLE MANAGEMENT –
OUTSIDE DIAMETERS OF CONDUITS FOR ELECTRICAL
INSTALLATIONS AND THREADS FOR CONDUITS AND FITTINGS

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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60423 has been prepared by subcommittee 23A: Cable
management systems, of IEC technical committee 23: Electrical accessories.
This third edition cancels and replaces the second edition published in 1993. This edition
constitutes a technical revision. The following main changes have been made to the second
edition:
– revised figures and tables plus editorial and normative reference updates;
– conduit range increased to 110 mm outside diameter.
The text of this standard is based on the following documents:
FDIS RVD
23A/541/FDIS 23A/545/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

– 4 – 60423 © IEC:2007
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result 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.
60423 © IEC:2007 – 5 –
INTRODUCTION
The mechanical performance of the threadable parts of the conduit system will be a function of
material and wall thickness, which is specified in the appropriate product standard (IEC 61386
series).
– 6 – 60423 © IEC:2007
CONDUIT SYSTEMS FOR CABLE MANAGEMENT –
OUTSIDE DIAMETERS OF CONDUITS FOR ELECTRICAL
INSTALLATIONS AND THREADS FOR CONDUITS AND FITTINGS

1 Scope
This International Standard specifies outside diameters for conduits used in electrical
installations or in communication systems and the dimensional requirements for threads. It also
specifies the dimensional requirements for threads used in associated fittings.
It is not applicable to extra heavy-duty electrical rigid steel conduits specified in IEC 60981.
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.
ISO 68-1:1998, ISO general purpose screw threads – Basic profile – Part 1: Metric screw
threads
ISO 965-1:1998, ISO general-purpose metric threads – Tolerances – Part 1: Principles and
basic data
ISO 1502:1996, ISO general-purpose metric screw threads – Gauges and gauging
3 Outside diameters and threads
The outside diameters, tolerances and details of threadable conduit and external and internal
metric threads are given in Table 1. Details of the thread form are given in Figure 1, which is
based on ISO 68-1 and ISO 965-1. Outside diameters and tolerances of non-threadable
conduit are given in Table 2.
4 Gauges
External threads are checked by means of threaded GO ring gauges and plain NO-GO ring
gauges specified in ISO 1502.
Internal threads are checked by means of threaded GO plug gauges and plain NO-GO plug
gauges specified in ISO 1502.
Outside diameters of threadable conduits are checked by means of GO ring gauges specified
in Figure 2 and NO-GO gap gauges specified in Figure 3a for threadable rigid metal conduits,
or NO-GO ring gauges specified in Figure 3b for threadable conduits other than rigid metal.

60423 © IEC:2007 – 7 –
Outside diameters of non-threadable conduits may be checked by any suitable measuring
technique.
5 Samples of conduit
The samples shall be (500 ± 5) mm in length.

– 8 – 60423 ©
...