ISO 461-1:2003

Aircraft - Connectors for ground electrical supplies - Part 1: Design, performance and test requirements

ISO 461-1:2003 specifies the design, performance and test requirements for electrical connectors used to supply electrical power from a ground source to an aircraft. ISO 461-2 specifies the dimensions of the connectors.

Aéronefs — Prises de courant d'alimentation au sol — Partie 1: Exigences concernant la conception, le fonctionnement et les essais

General Information

• Status: Published
• Publication Date: 25-May-2003
• ICS: 49.060 - Aerospace electric equipment and systems
• ICS: 49.100 - Ground service and maintenance equipment
• 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
• Start Date: 18-Jul-2025
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 461-1:1985 - Aircraft - Connectors for ground electrical supplies - Part 1: Design, performance and test requirements
• Effective Date: 15-Apr-2008

Overview

ISO 461-1:2003 - Aircraft - Connectors for ground electrical supplies - Part 1: Design, performance and test requirements defines the functional, mechanical and electrical requirements for connectors that transfer electrical power from ground sources to aircraft. It sets minimum criteria for construction, materials, environmental performance and safety testing of both the aircraft fixed connector (receptacle) and the ground supply free connector (plug). ISO 461-2 complements this part by specifying connector dimensions.

Key topics and technical requirements

• Scope and components: Requirements apply to mated pairs (fixed receptacle + free plug) used for supplying ground power to aircraft.
• Construction & materials: Connectors shall be robust, fungus-inert and corrosion-resistant; dissimilar metals must be protected against electrolytic corrosion.
• Temperature range: Engagement, disengagement and operation between −65 °C and +65 °C, and capability to operate at 105 °C allowing for temperature rise from current.
• Current and voltage ratings:
  • Main current contacts: 300 A continuous (Styles 1–3) or 350 A (Style 4).
  • Control contacts: 35 A continuous.
  • Voltage per ISO 461-2 (dimensioned part).
• Mechanical performance:
  • Engagement/disengagement force limits (e.g., 3-pin: max 223 N engage; disengage 134–223 N; Style 4: engage max 534 N).
  • Automatic uncoupling requirement for Style 4 to prevent damage if moved before uncoupling.
  • Side-load, shock and endurance cycling (e.g., 500 cycles) to verify mechanical durability.
• Electrical performance & tests:
  • Current overload test: 700 A (Styles 1–3) or 900 A (Style 4) for 3 min without damage; subsequent rated-current voltage-drop test.
  • Voltage-drop limits: ≤45 mV per large contact, ≤30 mV per small contact at rated current.
  • Salt spray exposure (48 h) and subsequent electrical checks.
  • High-voltage test: 2 000 V r.m.s. between adjacent contacts for 1 min; insulation resistance minimums (e.g., 100 MΩ, 20 MΩ for split contacts).
• Inspection & sampling: Defined type tests (11 samples) and quality control tests (1 pair per 100 units, at least annually).

Applications and who uses this standard

ISO 461-1 is essential for:

• Aircraft manufacturers and integrators specifying ground power interfaces.
• Ground support equipment (GSE) designers and suppliers of aircraft ground power units (GPUs) and cable assemblies.
• Maintenance organizations and MROs ensuring replacement connectors meet safety and performance criteria.
• Certification authorities, procurement teams and systems engineers verifying connector conformity.
  Practical uses include connector design validation, production quality control, procurement specifications, and maintenance acceptance testing.

Related standards

• ISO 461-2 - Dimensions for aircraft ground power connectors (companion document).
• ISO 7137 - Environmental conditions and test procedures (referenced for salt spray, vibration).
• Endorsement note: parts of the test regime reference EUROCAE ED-14 / RTCA DO-160 procedures.

For implementation, use ISO 461-1:2003 as the normative basis when designing, testing or procuring aircraft ground electrical connectors to ensure interoperability, safety and durability.

Standards Content (Sample)

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
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2003
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
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
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 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
...