SIST EN 3661-001:2025

SLOVENSKI STANDARD
01-marec-2025
Aeronavtika - Odklopniki, enopolni, temperaturno kompenzirani, naznačeni tok od
20 A do 50 A - 001. del: Tehnična specifikacija
Aerospace series - Circuit breakers, single-pole, temperature compensated, rated
currents 20 A to 50 A - Part 001: Technical specification
Luft- und Raumfahrt - Schutzschalter, einpolig, Temperaturkompensiert, Nennströme
von 20 A bis 50 A - Teil 001: Technische Lieferbedingungen
Série aérospatiale - Disjoncteurs unipolaires compensés en température, intensités
nominales 20 A à 50 A - Partie 001 : Spécification technique
Ta slovenski standard je istoveten z: EN 3661-001:2024
ICS:
49.060 Letalska in vesoljska Aerospace electric
električna oprema in sistemi equipment and systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 3661-001
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2024
EUROPÄISCHE NORM
ICS 49.060 Supersedes EN 3661-001:2006
English Version
Aerospace series - Circuit breakers, single-pole,
temperature compensated, rated currents 20 A to 50 A -
Part 001: Technical specification
Série aérospatiale - Disjoncteurs unipolaires Luft- und Raumfahrt - Schutzschalter, einpolig,
compensés en température, intensités nominales 20 A temperaturkompensiert, Nennströme von 20 A bis 50
à 50 A - Partie 001 : Spécification technique A - Teil 001: Technische Lieferbedingungen
This European Standard was approved by CEN on 6 October 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 3661-001:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 5
4 Description . 5
5 Design . 6
5.1 Materials . 6
5.1.1 Metallic materials . 6
5.1.2 Insulation materials . 6
5.2 Design . 6
5.2.1 Insulating box . 6
5.2.2 Free release mechanism . 6
5.2.3 Attachment . 6
5.2.4 Electrical connection units . 6
5.2.5 Control actuator . 7
5.2.6 Rating inviolability . 7
5.2.7 Leakage lines . 7
5.2.8 Protection against non-release . 7
6 Characteristics . 7
6.1 General characteristics . 7
6.2 Ratings . 8
6.3 Nominal voltage of main contacts . 8
6.4 Signal contact performances . 8
6.5 Dimensional characteristics . 8
6.6 Recommended panel mounting dimensions . 8
7 Tests . 9
7.1 Mechanical tests . 9
7.2 Environmental tests . 10
7.3 Electrical tests . 15
8 Qualification tests . 17
8.1 Sampling . 17
8.2 Material tests . 21
8.3 Periodic checks for qualification maintenance . 21
9 Quality assurance . 21
10 Marking . 21
11 Delivery conditions . 21
12 Packaging . 21
13 Storage . 21
13.1 Definition . 21
13.2 Storage conditions . 21
13.3 Storage duration . 22
Bibliography . 23

European foreword
This document (EN 3661-001:2024) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document shall be given the status of a national standard, either by publication of an identical text
or by endorsement, at the latest by June 2025, and conflicting national standards shall be withdrawn at
the latest by June 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 3661-001:2006.
The main changes with respect to the previous edition are as follows:
— EN 3661-001 (P4), 08/2006:
o g replaced by g-PK for sinusoidal and low frequencies;
n
o g replaced by Grms for random.
n
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this document: Austria, Belgium, Bulgaria, Croatia, Cyprus,
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
1 Scope
This document specifies the single-pole temperature compensated circuit breakers with signal contacts,
polarized or not, rated from 20 A to 50 A and used in aircraft on-board circuits. It describes specific
environmental, electrical and mechanical characteristics and the stringency of tests to be applied
according to test methods of EN 3841-100.
These circuit breakers are intended for use in aircraft with electrical supplies in accordance with
EN 2282.
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.
EN 2083, Aerospace series — Copper or copper alloy conductors for electrical cables — Product standard
EN 2825, Aerospace series — Burning behaviour of non-metallic materials under the influence of
radiating heat and flames — Determination of smoke density
EN 2826, Aerospace series — Burning behaviour of non-metallic materials under the influence of
radiating heat and flames —Determination of gas components in the smoke
EN 3841-100, Aerospace series — Circuit breakers — Test methods — Part 100: General
EN 3841-201, Aerospace series — Circuit breakers — Test methods — Part 201: Visual inspection
EN 3841-202, Aerospace series — Circuit breakers — Test methods — Part 202: Dimensions and masses
EN 3841-301:2004, Aerospace series — Circuit breakers — Test methods — Part 301: Voltage drop
EN 3841-302, Aerospace series — Circuit breakers — Test methods — Part 302: Insulation resistance
EN 3841-303, Aerospace series — Circuit breakers — Test methods — Part 303: Dielectric strength
EN 3841-304, Aerospace series — Circuit breakers — Test methods — Part 304: Tripping points
EN 3841-305, Aerospace series — Circuit breakers — Test methods — Part 305: Short-circuit performance
EN 3841-306, Aerospace series — Circuit breakers — Test methods — Part 306: Service life
EN 3841-307, Aerospace series — Circuit breakers — Test methods — Part 307: Performance with a
locked tripping system
EN 3841-308, Aerospace series — Circuit breakers — Test methods — Part 308: Lightning
EN 3841-401, Aerospace series — Circuit breakers — Test methods — Part 401: Sand and dust
EN 3841-402, Aerospace series — Circuit breakers — Test methods — Part 402: Corrosion
EN 3841-403, Aerospace series — Circuit breakers — Test methods — Part 403: Humidity

Published as ASD-STAN prEN at the date of publication of this document, available at:
https://www.asd-stan.org/.
EN 3841-404, Aerospace series — Circuit breakers — Test methods — Part 404: Explosion proofness
EN 3841-405, Aerospace series — Circuit breakers — Test methods — Part 405: Fluid resistance
EN 3841-406, Aerospace series — Circuit breakers — Test methods — Part 406: Flammability
EN 3841-501, Aerospace series — Circuit breakers — Test methods — Part 501: Actuator button travel
EN 3841-502, Aerospace series — Circuit breakers — Test methods — Part 502: Operating forces
EN 3841-503, Aerospace series — Circuit breakers — Test methods — Part 503: Strength of actuating
components
EN 3841-504, Aerospace series — Circuit breakers — Test methods — Part 504: Strength of mounting elements
EN 3841-505, Aerospace series — Circuit breakers — Test methods — Part 505: Strength of main terminals
EN 3841-506, Aerospace series — Circuit breakers — Test methods — Part 506: Vibration performance
EN 3841-507, Aerospace series — Circuit breakers — Test methods — Part 507: Mechanical shocks
EN 3841-508, Aerospace series — Circuit breakers — Test methods — Part 508: Centrifugal acceleration
EN 3841-509, Aerospace series — Circuit breakers — Test methods — Part 509: Insertion and extraction
forces of signal contact terminals
EN 3841-510, Aerospace series — Circuit breakers — Test methods — Part 510: Strength of signal contact
terminals
EN 3841-511, Aerospace series — Circuit breakers — Test methods — Part 511: Combined test:
temperature, altitude and vibration
EN 3844-1, Aerospace series — Flammability of non-metallic materials — Part 1: Small burner test,
vertical — Determination of the vertical flame propagation
MIL-I-81969/1A, Installing and removal tools, connector electrical contact, type III, class 2, composition C
MIL-I-81969/14C, Installing and removal tools, connector electrical contact, type III, class 2, composition B
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 3841-100 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/
4 Description
These circuit breakers are operated by a “push-pull” type single push button (actuator) and with
delayed action “trip-free” tripping. Their function is ensured up to the short-circuit current.

Published by Department of Defense (DOD), available at: https://assist.dla.mil/online/start/.
5 Design
5.1 Materials
5.1.1 Metallic materials
All metallic parts shall be resistant to corrosion or finished against corrosion. When dissimilar materials
are in close contact, an adequate protection against corrosion shall be used so that the electromotive
force of the galvanic couple does not exceed 0,25 V.
When bimetals are used, an eventual corrosion shall not affect the good operation of the circuit breaker.
5.1.2 Insulation materials
The insulating parts shall be made of auto-extinguishing or non-flammable materials; they shall not
emit damaging or explosive vapours, even in presence of fire or internal electric arc.
They shall be insensitive to moulds and microorganisms' action.
Application of any material or protective coating, which might crack, break or flake shall be forbidden.
Materials which are not specified, or which are not specially described shall be as light as possible for
the requested use.
Materials shall be selected according to security criteria (toxicity, smoke density) as defined in
contractual documents.
5.2 Design
5.2.1 Insulating box
The insulating box shall integrate besides the mechanism, the connection and attachment unit.
5.2.2 Free release mechanism
Design of circuit breaker mechanism shall allow free release, i.e. the circuit breaker cuts out in case of
overload, and remains cut out even if the actuator is kept by force in engaged position.
A new engagement of circuit breaker is only possible after a first total release of the control actuator.
The operation in these conditions shall not affect further performances of the circuit breaker.
5.2.3 Attachment
All visible parts shall be black coloured and non-reflective.
5.2.4 Electrical connection units
They shall be able to receive the lugs (or contacts).
5.2.5 Control actuator
In engaged position, the visible part of the control actuator shall be of the colour stated in the product
standard. In disengaged (or opened) position, the control actuator shall show a white strip.
The outer part of this actuator shall be isolated from all undervoltage parts.
The control actuator shall not stay in a transition position or give a false indication about the circuit
breaker condition. It shall not be removable.
When pushing it, power contacts of the circuit breaker engage and indicating contact opens.
When pulling it, power contacts of the circuit breaker open and indicating contact closes.
The circuit breaker rating is indicated in indelible white colour on the front part of the control actuator.
The product standard gives the digits positioning.
5.2.6 Rating inviolability
The circuit breaker shall be designed in such a way that the calibration unit cannot be reached without
breaking a sealing.
5.2.7 Leakage lines
The leakage lines and the minimal space to be foreseen between the undervoltage parts and any other
part of the circuit breaker made of non-insulating material, as well as between the undervoltage parts of
opposite polarity, shall be sufficient to avoid any default or arc tracking in all uses and climatic conditions.
5.2.8 Protection against non-release
Electrical overload happening on a circuit breaker locked in its engaged position (sticked contacts or
non-operating release mechanism), shall cause the opening of the circuit-by-circuit breaker destruction
without any fire or important smoke release.
6 Characteristics
6.1 General characteristics
General characteristics shall be according to Table 1.
Table 1 — General characteristics
Designati
...