SIST EN 3841-302:2005

Aerospace series - Circuit breakers - Test methods - Part 302: Insulation resistance

This standard specifies a method of verifying the insulation resistance of circuit breakers.
It shall be used together with EN 3841-100.

Luft- und Raumfahrt - Schutzschalter - Prüfverfahren - Teil 302: Isolationswiderstand

Série aérospatiale - Disjoncteurs - Méthodes d'essais - Partie 302 : Résistance d'isolement

La présente norme spécifie une méthode pour vérifier la résistance d'isolement.
Elle doit être utilisée conjointement avec EN 3841-100.

Aeronavtika - Odklopniki - Preskusne metode - 302. del: Izolacijska upornost

General Information

• Status: Published
• Publication Date: 31-Mar-2005
• ICS: 49.060 - Aerospace electric equipment and systems
• Technical Committee: SS SPL - Technical Board for the general field
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Apr-2005
• Due Date: 01-Apr-2005
• Completion Date: 01-Apr-2005
• Ref Project: EN 3841-302:2004 - Aerospace series - Circuit breakers - Test methods - Part 302: Insulation resistance

Relations

• Refers: SIST EN 3841-100:2024 - Aerospace series - Circuit breakers - Test methods - Part 100: General
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 474-5:2007+A3:2014 - Earth-moving machinery - Safety - Part 5: Requirements for hydraulic excavators
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 474-1:2007+A5:2018 - Earth-moving machinery - Safety - Part 1: General requirements
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 474-4:2007+A2:2012 - Earth-moving machinery - Safety - Part 4: Requirements for backhoe loaders
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 2995-001:2024 - Aerospace series - Circuit breakers, single-pole, temperature compensated, rated currents 1 A to 25 A - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 4839-001:2018 - Aerospace series - Arc fault circuit breakers, three-poles, temperature compensated, rated current 3 A to 25 A - 115 V a.c. 400 Hz constant frequency - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 474-1:2007+A6:2019 - Earth-moving machinery - Safety - Part 1: General requirements
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 474-1:2007+A1:2009 - Earth-moving machinery - Safety - Part 1: General requirements
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 3774-001:2025 - Aerospace series - Circuit breakers, three-pole, temperature compensated, rated currents 1 A to 25 A - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 3774-001:2015 - Aerospace series - Circuit breakers, three-pole, temperature compensated, rated currents 1 A to 25 A - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 3661-001:2025 - Aerospace series - Circuit breakers, single-pole, temperature compensated, rated currents 20 A to 50 A - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 3773-001:2025 - Aerospace series - Circuit breakers, single-pole, temperature compensated, rated currents 1 A to 25 A - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 500-3:2007+A1:2008 - Mobile road construction machinery - Safety - Part 3: Specific requirements for soil-stabilising machines and recycling machines
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 4838-001:2018 - Aerospace series - Arc Fault Circuit breakers, single-pole, temperature compensated, rated current 3 A to 25 A - 115 V a.c. 400 Hz Constant Frequency - Part 001: Technical specification
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 2665-001:2014 - Aerospace series - Circuit breakers, three-pole, temperature compensated, rated current 20 A to 50 A - Part 001: Technical specification
• Effective Date: 28-Jan-2026

Overview

SIST EN 3841-302:2005 - Aerospace Series - Circuit Breakers - Test Methods - Part 302: Insulation Resistance is a European standard developed by CEN to define a consistent method for verifying the insulation resistance of circuit breakers in aerospace applications. Part of the broader EN 3841 series, this document is crucial to ensuring the safe and reliable electrical performance of circuit breakers used in aircraft electrical systems. SIST EN 3841-302:2005 must be applied in conjunction with EN 3841-100, which sets out general testing requirements for aerospace circuit breakers.

Key Topics

• Insulation Resistance Testing: The main focus of SIST EN 3841-302:2005 is on the measurement method for evaluating insulation resistance in circuit breakers. This is critical for preventing unwanted current flow and ensuring system safety and reliability.

• Testing Procedure: The standard prescribes testing insulation resistance at 500 V d.c., both with circuit breakers in the open (off) and closed (on) positions. Measurements are taken:

  • Between terminals of each pole and all other connections, including signal contacts.
  • Between all connections (including signal contacts) and earth (mounting).

• Test Conditions: Measurements must be conducted after temperature and pressure have stabilized and must meet values required by the relevant technical specification for all admissible temperatures at ground level.

• Compliance: Only circuit breakers that fulfill the stipulated insulation resistance requirements for ground-level temperatures are compliant.

Applications

SIST EN 3841-302:2005 is a vital reference for:

• Aerospace Manufacturers and Suppliers: Companies specializing in the manufacture or supply of aircraft circuit breakers must use this standard to validate component design, development, and quality control processes.

• Testing Laboratories: Accredited labs performing acceptance, type, or qualification testing on circuit breakers for aerospace use must use SIST EN 3841-302:2005 to ensure industry-standard assessment and compliance.

• Aircraft Maintenance and Engineering: Maintenance, repair, and overhaul (MRO) organizations rely on the results of these insulation resistance tests to diagnose issues and certify aircraft circuit breakers for continued airworthiness, thus supporting aviation safety protocols.

• Standardization and Certification Bodies: Organizations responsible for component approval and certification use this standard to benchmark compliance for electrical equipment used in aerospace systems.

Related Standards

For comprehensive circuit breaker testing and qualification, SIST EN 3841-302:2005 should be used in conjunction with the following documents:

• EN 3841-100: Aerospace series - Circuit breakers - Test methods - Part 100: General requirements (essential companion standard outlining overall testing frameworks).
• Other EN 3841 Parts: Additional documents in the EN 3841 series detail specific test methods for different quality and performance characteristics of aerospace circuit breakers.
• National and International Aerospace Standards: SIST EN 3841-302:2005 is harmonized across Europe; similar principles may apply in standards such as AS or MIL-specs for international or military aerospace applications.

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By following the procedures outlined in SIST EN 3841-302:2005, stakeholders across aerospace manufacturing, testing, and maintenance can ensure the electrical integrity and reliability of circuit breakers, supporting both operational safety and regulatory compliance. For any organization involved with aerospace electric equipment and systems, adherence to this insulation resistance testing standard is essential.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2005
Aeronavtika - Odklopniki - Preskusne metode - 302. del: Izolacijska upornost
Aerospace series - Circuit breakers - Test methods - Part 302: Insulation resistance
Luft- und Raumfahrt - Schutzschalter - Prüfverfahren - Teil 302: Isolationswiderstand
Série aérospatiale - Disjoncteurs - Méthodes d'essais - Partie 302 : Résistance
d'isolement
Ta slovenski standard je istoveten z: EN 3841-302:2004
ICS:
49.060 /HWDOVNDLQYHVROMVND Aerospace electric
HOHNWULþQDRSUHPDLQVLVWHPL equipment and systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 3841-302
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2004
ICS 49.060
English version
Aerospace series - Circuit breakers - Test methods - Part 302:
Insulation resistance
Série aérospatiale - Disjoncteurs - Méthodes d'essais - Luft- und Raumfahrt - Schutzschalter - Prüfverfahren - Teil
Partie 302 : Résistance d'isolement 302: Isolationswiderstand
This European Standard was approved by CEN on 10 September 2004.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 3841-302:2004: E
worldwide for CEN national Members.

Contents Page
1 Scope .4
2 Normative references .4
3 Method .
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