ISO 2635:2003

Aircraft — Conductors for general purpose aircraft electrical cables and aerospace applications — Dimensions and characteristics

ISO 2635:2003 specifies the dimensions, electrical characteristics and mechanical characteristics of multi-strand conductors for general-purpose aircraft electrical cables and aerospace applications. It applies to stranded conductors over the nominal cross-sectional area range 0,12 mm2 to 107 mm2 inclusive. It is not applicable to conductors for fire-resistant cables or for thermocouple extension cables. Conductors for fire-resistant cables are specified in ISO 1967 and for thermocouple extension cables are specified in ISO 8056-1.

Aéronefs — Conducteurs pour câbles électriques pour usage général aéronautique et pour applications aérospatiales — Dimensions et caractéristiques

General Information

• Status: Published
• Publication Date: 16-Nov-2003
• ICS: 49.060 - Aerospace electric equipment and systems
• Technical Committee: ISO/TC 20/SC 1 - Aerospace electrical requirements
• Drafting Committee: ISO/TC 20/SC 1 - Aerospace electrical requirements
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 23-Aug-2021

Relations

• Amended By: ISO 2635:2003/Amd 1:2017 - Aircraft — Conductors for general purpose aircraft electrical cables and aerospace applications — Dimensions and characteristics — Amendment 1: Correction of table 1
• Effective Date: 07-Aug-2021
• Revises: ISO 2635:1979 - Aircraft — Conductors for general purpose aircraft electrical cables and aerospace applications — Dimensions and characteristics
• Effective Date: 15-Apr-2008
• Consolidated By: ISO 16610-71:2014 - Geometrical product specifications (GPS) — Filtration — Part 71: Robust areal filters: Gaussian regression filters
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 2635
Second edition
2003-11-15

Aircraft — Conductors for general
purpose aircraft electrical cables and
aerospace applications — Dimensions
and characteristics
Aéronefs — Conducteurs pour câbles électriques pour usage général
aéronautique et pour applications aérospatiales — Dimensions et
caractéristiques




Reference number
ISO 2635:2003(E)
©
ISO 2003

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ISO 2635:2003(E)
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ISO 2635:2003(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 2635 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 1,
Aerospace electrical requirements.
This second edition cancels and replaces the first edition (ISO 2635:1979), which has been technically revised.
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ISO 2635:2003(E)
Introduction
The need for International Standardization in the Aerospace industry cannot be overemphasized. Multinational
projects abound in the construction industry and all major airlines use equipment produced in different
continents. The mixture of specifications and standards combine to increase the chances of maintenance
errors, no more so than in the interconnection system. Power plant manufacturers in France may use
conductors and terminations manufactured in Europe mating at the firewall with terminations and conductors
manufactured in North America. This can result in different contacts, crimp tools and settings, and insulating
stripping tools being required to work on mating connectors. The same would apply to many types of
equipment.
The requirement for close or “clipped” tolerance, lightweight conductors can provide the opportunity to
address many of these problems by overcoming the long-standing issue of AWG versus metric sizes.
This revision of ISO 2635 introduces a list of lightweight conductors for airframe cables. This list supplements
the existing list of standard metric conductors which has not received worldwide acceptance. The list is
derived from NEMA standard WC 67 which includes the constructions in previous and existing specifications
ISO 2635:1979, EN 2083, prEN 4434, BS 3G 231 and MIL-W-29606. It has also been compared with those
used by airframe constructors. The conductor codes in Table 1 are taken from WC 67.
The constructions presented are those which are considered to be standards within the existing rules
governing aircraft cables, e.g. 19 strands minimum, copper alloy for size 24 and smaller. However, it does
take advantage of the lightest weight for each size. The resultant standard is therefore a mixture of conductors
with metric and imperial origins which gives the greatest advantage to constructors and users for the future.
This International Standard:
 obeys existing rules regarding conductors for aircraft;
 gives the lightest weight for each size/rating presently used;
 standardizes the conductor cross sectional area throughout the world aerospace industry;
 enables the standardization of terminations and the crimp tools used to produce the joints;
 reduces the number of insulation stripping tools required to service aircraft;
 enables the world industry to concentrate its efforts on improving interconnection technology knowing that
a world market exists;
 enables regulatory authorities (CAA, FAA, JAA, etc.) to make rules regarding the interconnection system
which applies internationally.
All these will, by reducing complexity, reduce servicing errors and contribute to aircraft safety.
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INTERNATIONAL STANDARD ISO 2635:2003(E)

Aircraft — Conductors for general purpose aircraft electrical
cables and aerospace applications — Dimensions and
characteristics
1 Scope
This International Standard specifies the dimensions, electrical characteristics and mechanical characteristics
of multi-strand conductors for general-purpose aircraft electrical cables and aerospace applications. It applies
2 2
to stranded conductors over the nominal cross-sectional area range 0,12 mm to 107 mm inclusive.
It is not applicable to conductors for fire-resistant cables or for thermocouple extension cables. Conductors for
fire-resistant cables are specified in ISO 1967 and for thermocouple extension cables are specified in
ISO 8056-1.
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 8815, Aircraft — Electrical cables and cable harnesses — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8815 and the following apply.
3.1
conductor code
numeric or alphanumeric code which designates conductor size and properties

3.2
worldwide wire gauge
WWG
identification system, similar to the American wire gauge (AWG) system from which it has been derived, for an
international designation of wire cable sizes
4 Required characteristics
4.1 General
The dimensions, electrical resistance, mechanical properties and mass of the conductors shall conform to the
values given in Table 1 or Table 2. Table 2 should be used for new designs.
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ISO 2635:2003(E)
4.2 Materials
2 2
4.2.1 Conductors of nominal cross-sectional area 0,25 mm to 0,12 mm shall be produced from high-
2
strength copper alloy, and conductors of nominal cross-sectional areas greater than 0,25 mm shall be
produced in copper of electrotechnical quality (i.e. ETP grade copper).
4.2.2 Conductors shall be manufactured from unused materials that have been exposed only to processes
essential to their manufacture and application.
4.2.3 Size 24 and smaller conductors shall be made from high strength copper alloy. The larger sizes shall
be electrotechnical grade copper.
NOTE No ISO standards are available which specify aircraft grade copper and copper alloys.
4.2.4 The plating materials shall conform to the appropriate requirements of Clause 6.
4.2.5 These conductors in copper and copper alloy may be unplated (code letter A), tinned (code letter B),
silver-plated (code letter C) or nickel-plated (code letter D) in accordance with the requirements of, and to the
thickness required by, the individual specification for which the conductors are being used. The thickness of
the silver-plating (code letter C) shall be at least 1,0 µm and the thickness of the nickel-plating, (code letter D),
at least 1,25 µm.
5 Construction
5.1 Table 1 gives the number of strands to be used for each cro
...