ISO 461-1:2003

INTERNATIONAL ISO
STANDARD 461-1
Second edition
2003-06-01
Aircraft — Connectors for ground
electrical supplies —
Part 1:
Design, performance and test
requirements
Aéronefs — Prises de courant d'alimentation au sol —
Partie 1: Exigences concernant la conception, le fonctionnement et les
essais
Reference number
©
ISO 2003
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ii © ISO 2003 — All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 Design and performance requirements . 2
5 Inspection and testing. 3
6 Marking and ordering procedures. 6

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
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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
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rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 461-1 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 461-1:1985), which has been technically
revised. This edition brings the document up to date in terms of the connectors now being used on aircraft and
anticipates future requirements. The testing regime for connectors has been changed to reflect existing
industry practices.
ISO 461 consists of the following parts, under the general title Aircraft — Connectors for ground electrical
supplies:
 Part 1: Design, performance and test requirements
 Part 2: Dimensions
iv © ISO 2003 — All rights reserved

Introduction
Throughout this part of ISO 461, the minimum essential criteria are identified by the use of the imperative or
the key word “shall”. Recommended criteria are identified by the use of the key word “should” and, while not
mandatory, are considered to be of primary importance in providing serviceable, economical and practical
connectors. Deviation from the recommended criteria should occur only after careful consideration, extensive
testing and thorough service evaluation have shown alternative methods to be satisfactory.
INTERNATIONAL STANDARD ISO 461-1:2003(E)

Aircraft — Connectors for ground electrical supplies —
Part 1:
Design, performance and test requirements
1 Scope
This part of ISO 461 specifies the design, performance and test requirements for electrical connectors used to
supply electrical power from a ground source to an aircraft.
NOTE ISO 461-2 specifies the dimensions of the connectors.
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 461-2, Aircraft — Connectors for ground electrical supplies — Part 2: Dimensions
1)
ISO 7137, Aircraft — Environmental conditions and test procedures for airborne equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
aircraft fixed connector (receptacle)
connector, installed in an aircraft, which accepts an electrical power supply via the ground supply free
connector from an external ground source
3.2
ground supply free connector (plug)
connector, fitted to cables from the external ground source of electrical power, which, when properly fitted to
the aircraft fixed connector, permits an electrical supply to be passed to the aircraft

1) Endorsement, in part, of the publication EUROCAE ED-14/RTCA DO-160 (a document published jointly by the
European Organization for Civil Aviation Electronics and the Radio Technical Commission for Aeronautics).
4 Design and performance requirements
4.1 General
4.1.1 Construction
The ground supply free connector shall be robust in construction and capable of withstanding heavy
mechanical shocks and hard wear in use, and shall be designed to provide safe handling, for example by the
avoidance of sharp edges.
4.1.2 Fungus resistance
Materials used in the construction of fixed and free connectors shall be fungus-inert.
4.1.3 Metallic materials
Metals used shall be corrosion-resistant or treated to resist corrosion.
4.1.4 Dissimilar materials
Dissimilar materials used in intimate contact shall be protected against electrolysis and electrolytic corrosion.
4.1.5 Temperatures
Aircraft fixed connectors and ground supply free connectors shall be capable of engagement, disengagement
and operation at ambient temperatures between − 65 °C and + 65 °C. They shall be capable of operating at
105 °C, allowing for the temperature rise due to current carried by the connectors.
4.1.6 Automatic uncoupling
Style 4 connectors shall be equipped with a positive-coupling device which will release automatically, without
damage to the aircraft fixed connector or its mounting, should the aircraft or ground supply move before
uncoupling has been carried out.
4.2 Polarity or phase sequence
Indications of polarity or phase shall be permanently marked on the aircraft fixed connectors and the ground
supply free connectors at points adjacent to the contacts, as indicated in the relevant figures in ISO 461-2.
The markings shall be permanent and legible and shall be marked on the front and rear of the insert of the
aircraft fixed connector.
4.3 Current ratings
4.3.1 Each of the main current-carrying contacts of the fixed and free connectors (as distinct from any
cables connected to them) shall be capable of carrying up to 300 A (Styles 1, 2 and 3) or 350 A (Style 4)
continuously, i.e. for 1 h or more (direct current or r.m.s. alternating current).
4.3.2 Each of the control male and female contacts shall be capable of carrying 35 A continuously.
4.4 Control current female contact
The control current female contact of the d.c. ground supply free connector may be in two sections, insulated
electrically from each other, connected only by the entry of the control male contact of the aircraft fixed
connector, or the female contact may be of a one-piece construction.
2 © ISO 2003 — All rights reserved

4.5 Voltage rating
The aircraft fixed connectors and ground supply free connectors shall be capable of working continuously at
the voltages specified in ISO 461-2.
4.6 Replaceability of contacts in the ground supply free connectors
All the ground supply free connectors shall be capable of being replaced or repaired such that the existing
cables attached to the ground supply free connector may be reused.
5 Inspection and testing
5.1 Inspection
Connectors shall be examined to ensure that they meet the requirements of this part of ISO 461 and the
dimensional requirements of ISO 461-2.
5.2 Testing
5.2.1 Type tests
Type tests shall be carried out to prove conformance to the requirements of this part of ISO 461. Unless
otherwise indicated, the tests shall be conducted at an ambient temperature between 15 °C and 25 °C. The
tests specified in 5.3.1 to 5.3.10 shall be conducted on 11 test samples (A to K) using the sample allocation
and the test order given in Table 1. Each sample shall consist of an aircraft fixed connector and an
appropriate ground supply free connector.
5.2.2 Quality control tests
Quality control tests shall be made on one fixed and free connector per 100, at least once a year. The sample
shall be subjected to the tests specified in 5.3.4.1 and 5.3.6. If the sample fails any test, the batch shall be
deemed not to conform to the requirements of this part of ISO 461.
Table 1 — Type testing — Allocation of samples and order of testing
Sample and test order
Test
A B C
Engagement and disengagement forces (see 5.3.1) 1
Side-load test (see 5.3.2) 2
Endurance (see 5.3.3) 3
Current overload and voltage drop test (see 5.3.4) 4
Salt spray test (see 5.3.5) 1
High-voltage and insulation resistance test (see 5.3.6) 2
Vibration test (aircraft fixed connector only) (see 5.3.7) 3
Shock test (ground supply free connector only) (see 5.3.8)  1
Extremes of temperature — Engagement and disengagement test  2
(see 5.3.10)
Fluid susceptibility test (initial qualification only) (see 5.3.9) Samples D to K (one per fluid)
5.3 Tests
5.3.1 Engagement and disengagement forces
5.3.1.1 Styles 1, 2 and 3
Two test fixed connectors shall be constructed for each configuration of ground supply free connector, each
fixed connector having male contacts of hardened and ground steel, with a surface finish of between 0,1 µm
and 0,4 µm (4 µin and 16 µin), mounted at the centres shown in the appropriate figure in ISO 461-2, except
that the tolerance on contact position shall be ± 0,025 mm (± 0,001 in). No shrouds shall be fitted.
One test fixed connector shall have male contacts of the maximum tolerance dimension ± 0,005 mm
(± 0,000 2 in) and the other test fixed connector shall have male contacts of the minimum tolerance dimension
± 0,005 mm (± 0,000 2 in).
Fully engage and disengage the ground supply free connector being tested 50 times using the maximum size
test fixed connector followed by 5 times using the minimum size test fixed connector. Engagement and
complete separation may be accomplished by machine.
Measure the force necessary to engage and disengage the ground supply free connector on the first and last
insertion of each test fixed connector. For 3-pin connectors, the engaging force shall not be greater than
223 N (50 lbf) and the disengaging force shall be between 134 N and 223 N (30 lbf to 50 lbf). For 5- and 6-pin
connectors, the engaging force shall not be greater than 445 N (100 lbf) and the disengaging force shall be
between 267 N and 445 N (60 lbf to 100 lbf). The rate of insertion and withdrawal shall be 177 mm/min to
229 mm/min (7 in/min to 9 in/min).
5.3.1.2 Style 4
The engaging force shall not be greater than 534 N (120 lbf) and the disengaging force shall be between
400 N and 534 N (90 lbf to 120 lbf).
5.3.2 Side-load test
5.3.2.1 Styles 1, 2 and 3
After the test described in 5.3.1.1, engage the ground supply free connector with an appropriate aircraft fixed
connector mounted with its axis horizontal.
With the main current-carrying male contacts one-third engaged, apply a side load of 890 N (200 Ibf) to the
extremity of the ground supply free connector body. No damage or permanent deformation of the fixed or free
connector shall ensue from this test.
5.3.2.2 Style 4
After the test described in 5.3.1.2, engage and latch the ground supply free connector with an appropriate
aircraft fixed connector mounted with its axis horizontal. Apply a side load of 890 N (200 lbf) to the extremity of
the ground supply free connector b
...