ISO 1509:2024

General purpose push-pull three-pole circuit-breakers for aircraft - Performance requirements

This document specifies the performance requirements for push-pull, three-pole, trip-free circuit breakers having an inverse time/current characteristic of normal ratings up to and including 35 A for use in nominal 115 V/200 V three-phase 400 Hz a.c. circuits.

Disjoncteurs tripolaires à bouton-poussoir d'usage courant utilisés à bord des aéronefs — Caractéristiques

General Information

• Status: Published
• Publication Date: 08-Apr-2024
• 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: 6060 - International Standard published
• Start Date: 09-Apr-2024
• Due Date: 23-Aug-2024
• Completion Date: 09-Apr-2024

Relations

• Revises: ISO 1509:1973 - General purpose push-pull three-pole circuit-breakers for aircraft - Performance requirements
• Effective Date: 06-Jun-2022

Overview

ISO 1509:2024 specifies performance requirements for general purpose push‑pull three‑pole circuit‑breakers for aircraft. It covers trip‑free, inverse time/current characteristic circuit‑breakers with normal ratings up to and including 35 A for use in nominal 115 V / 200 V three‑phase 400 Hz a.c. aircraft power systems. The standard defines what manufacturers, integrators and certifying authorities need to verify reliable electrical protection components for onboard three‑phase circuits.

Key topics and requirements

ISO 1509:2024 addresses design, construction and verification across the product lifecycle:

• Scope & definitions - device classification, operating concepts (push‑pull, trip‑free).
• Design requirements - ambient temperature, altitude, operation instructions, fixing type, re‑close and working characteristics.
• Dimensions & construction - push‑button design, surface treatment, electrical connections, fasteners, rating inviolability.
• Voltage and current ratings - applicable for 115/200 V three‑phase 400 Hz systems, rated currents up to 35 A.
• Time/current characteristics - inverse time/current trip behaviour and calibration requirements.
• Making and breaking capacity & endurance - requirements for short‑circuit and switching performance.
• Environmental and mechanical tests - vibration, acceleration, mechanical shock, climatic, low temperature self‑reclose.
• Electrical tests - high voltage, insulation resistance, temperature rise, magnetic influence.
• Production & quality tests - factory calibration, voltage drop, holding current, sample selection and marking.
• Documentation & marking - declarations, rated current marking and product identification.

Applications and who uses it

ISO 1509:2024 is essential for stakeholders involved in aircraft electrical power systems:

• Manufacturers of aircraft circuit‑breakers and panel components - to design and qualify products to industry expectations.
• Airframe and systems engineers - to select compliant protection devices for 115/200 V, 400 Hz three‑phase distribution.
• Avionics and electrical integration teams - to ensure compatibility, mounting, and environmental resilience.
• MROs and maintenance organizations - to verify replacement parts and post‑repair performance.
• Procurement and certification bodies - to reference consistent test and marking requirements in supply contracts and certification dossiers.

Related standards

ISO 1509 complements other aircraft electrical and safety standards (electrical connectors, wiring, power distribution and environmental testing standards). Use it alongside airworthiness and system‑level regulations to ensure compliant component selection and testing.

Keywords: ISO 1509:2024, push‑pull three‑pole circuit‑breakers, aircraft circuit breakers, 115 V/200 V three‑phase 400 Hz, trip‑free, inverse time/current, circuit‑breaker performance requirements.

Standards Content (Sample)

International
Standard
ISO 1509
Second edition
General purpose push-pull three-
2024-04
pole circuit-breakers for aircraft —
Performance requirements
Disjoncteurs tripolaires à bouton-poussoir d'usage courant
utilisés à bord des aéronefs — Caractéristiques
Reference number
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
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Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design requirements . 1
4.1 Ambient temperature and altitudes .1
4.2 Operation and instructions .2
4.3 Fixing type .2
4.4 Trip-free function.2
4.5 Working characteristics .2
4.6 Re-close .2
5 Dimensions . 2
6 Construction . 2
6.1 Push-button .2
6.2 Operation forces .2
6.3 Surface treatment .2
6.4 Rating inviolability .2
6.5 Electrical connections.3
6.6 Fasteners .3
7 Voltage and current ratings . 3
7.1 Voltage .3
7.2 Current ratings .3
8 Environment . 3
9 Time/current characteristics . 3
10 Making and breaking capacity . 4
11 Endurance . 4
12 Tests . 4
12.1 General .4
12.2 Requirements .4
12.3 Test conditions .5
13 Type tests . 5
13.1 General .5
13.2 Requirements .5
13.3 Vibration test .5
13.4 Acceleration and mechanical shocks tests .5
13.4.1 Acceleration test .5
13.4.2 Mechanical shocks test .6
13.5 Climatic test .6
13.6 High voltage and insulation tests .6
13.6.1 High voltage test .6
13.6.2 Insulation resistance tests .6
13.7 Test of explosion-proofness .6
13.8 Measurement of magnetic influence .7
13.9 Tests of temperature rise and minimum and maximum limit of ultimate trip current .7
13.10 Operating forces test .7
13.11 Mechanical strength tests .7
13.11.1 Strength of terminations . . .7
13.11.2 Strength of push-button .7

iii
13.11.3 Strength of panel mounting bush .8
13.11.4 Tests .8
13.12 Test of calibration of overload trip .8
13.12.1 General .8
13.12.2 Additional requirements .8
13.13 Overload and re-closure test .8
13.13.1 General .8
13.13.2 Requirement .8
13.13.3 Tests .9
13.14 Endurance tests .9
13.14.1 General .9
13.14.2 Test conditions .9
13.14.3 Requirements .9
13.14.4 Tests .10
13.15 Making and breaking capacity tests .10
13.15.1 General .10
13.15.2 Test conditions .11
13.15.3 Tests .11
13.16 Test of self re-closing at low temperature . 12
14 Production tests .12
14.1 Calibration tests . 12
14.1.1 General . 12
14.1.2 Voltage drop tests . 12
14.1.3 Time/current characteristics tests . 12
14.1.4 Tests . 12
14.1.5 Holding current test . 12
14.1.6 Tests . 12
14.2 High voltage and insulation tests . 12
15 Quality tests .12
15.1 Selection of samples . 12
15.2 Tests of minimum and maximum limit of ultimate trip current . 13
15.3 Operating force test . 13
15.4 Test of calibration of overload trip . 13
15.5 Vibration test . 13
15.6 Strip examination and report . 13
16 Declarations .13
17 Marking . .13
17.1 General . 13
17.2 Rated current marking . . .14

iv
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
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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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document 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 1509:1973), which has been technically
revised.
The main changes are as follows:
— ambient temperature and altitudes have been updated;
— operation forces have been updated;
— time/current characteristics have been updated;
— mechanical shocks test have been updated;
— high voltage and insulation tests have been updated;
— tests of temperature rise and minimum and maximum limit of ultimate trip current have been updated;
— operating forces test have been updated;
— mechanical strength tests have been updated;
— overload and re-closure test have been updated.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
Introduction
This document provides performance requirements of the general purpose push-pull three-pole circuit-
breakers normal ratings up to and including 35 A for aircraft.
The purpose of this document are as follows:
a) To standardize the requirements for push-pull three-pole trip-free circuit-breakers that are physically
and environmentally diversified.
b) To provide the applicable document for push-pull three-pole trip-free circuit-breakers.
In order to satisfy the purpose of this document, requirements such as those for physical, environmental
and individual items are specified in accordance with the detail requirements that are issued individually.

vi
International Standard ISO 1509:2024(en)
General purpose push-pull three-pole circuit-breakers for
aircraft — Performance requirements
1 Scope
This document specifies the performance requirements for push-pull, three-pole, trip-free circuit breakers
having an inverse time/current characteristic of normal ratings up to and including 35 A for use in nominal
115 V/200 V three-phase 400 Hz a.c. circuits.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 2635, Aircraft — Conductors for general purpose aircraft electrical cables and aerospace applications —
Dimensions and characteristics
ISO 1033, Aircraft — Dimensions for general purpose push-pull three-pole circuit-breakers
ISO 1540, Aerospace — Characteristics of aircraft electrical systems
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.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
push-pull three-pole circuit-breaker
circuit-breaker with a single button to trip and reset the breaker, by pushing to make and pulling to break
3.2
trip-free circuit-breaker
Circuit-breaker so designed that holding the push-button in the closed position does not override the tripping
mechanism and does not permit subsequent closure of the contacts, until the push-button has been returned
to the open position and the tripping mechanism has reset
4 Design requirements
4.1 Ambient temperature and altitudes
The circuit-breaker shall be suitable for use at specified ambient temperatures and altitudes. There are
two temperature ranges: −55 °C to +70 °C or −55 °C to +125 °C; and the maximum altitude according to the
product standard shall not be less than 22 000 m.

4.2 Operation and instructions
The circuit-breaker shall be operated by a single button, perpendicular to the plane of the mounting panel,
pushed to make and pulled to break the circuit. The portion of the button visible when the circuit-breaker is
in the closed position shall be black. A white band on the button shall be exposed when the circuit-breaker is
in the open position.
4.3 Fixing type
The circuit-breaker shall be suitable for through-panel mounting, preferably by single-hole fixing, and shall
operate satisfactorily when mounted in any attitude.
4.4 Trip-free function
The circuit-breaker shall be trip-free and shall incorporate an automatic overload tripping device in each pole.
4.5 Working characteristics
The three sets of contacts shall open and close together when manually operated at normal load and shall
open together when automatically tripped on overload current in one or more lines, when the push-button
shall move to the open or off position. The difference in time between the making or breaking of the three
sets of contacts shall be not more than 5 ms.
4.6 Re-close
The circuit-breaker shall be so designed that, after tripping on overload, it cannot re-close automatically.
5 Dimensions
The envelope and fixing dimensions for the circuit-breakers should conform to ISO 1033.
6 Construction
6.1 Push-button
The push-button shall be insulated from all current-carrying parts, and shall not remain
...