prEN 2794-004
(Main)Aerospace series - Circuit breakers, single-pole, temperature compensated, rated currents 20 A to 60 A - Part 004: UNC thread terminals - Product standard
General Information
- Abstract
This document specifies the characteristics of single-pole circuit breakers, temperature compensated with a rated current from 20 A to 25 A, used in aircraft on-board circuits at a temperature between −55 °C and 125 °C and at an altitude of 15 000 m max.
These circuit breakers are operated by a push-pull type single push button (actuator), with delayed action “trip-free” tripping.
They will continue to function up to the short-circuit current.
- Status
- Not Published
- Publication Date
- 07-Feb-2028
- Technical Committee
- ASD-STAN - Aerospace
- Drafting Committee
- ASD-STAN/D 2/S 5 - Protection Devices
- Current Stage
- 4020 - Submission to enquiry - Enquiry
- Start Date
- 13-Aug-2026
- Completion Date
- 13-Aug-2026
Overview
prEN 2794-004 is a draft European standard developed by CEN for aerospace applications. It specifies requirements for single-pole, temperature compensated circuit breakers with rated currents from 20 A to 60 A, specifically focusing on products with UNC thread terminals. These circuit breakers are designed for use in aircraft onboard electrical systems, operating reliably in severely demanding conditions-temperatures between −55 °C and 125 °C and altitudes up to 15,000 meters.
The standard ensures that such circuit breakers provide both thermal and mechanical robustness, withstand harsh environmental factors, and offer consistent protection for aircraft electrical circuits. The devices feature a push-pull single button actuator with "trip-free" delayed action tripping, and they are engineered to maintain functionality even up to rated short-circuit currents.
Key Topics
Temperature Compensated Single-Pole Design
Ensures stable tripping performance over a wide temperature range.Current Ratings and Application Limits
Supports a broad selection of rated currents (20 A–60 A), suitable for various onboard loads.UNC Threaded Terminals
Establishes requirements for terminal threads, supporting reliable installation and maintenance with standard aerospace hardware.Operability at Extreme Altitudes
Qualified for performance up to 15,000 meters, ensuring reliability in both pressurized and unpressurized locations within the aircraft.Mechanical and Environmental Endurance
Covers resistance to vibration, shock, humidity, corrosion, and contaminating liquids, as well as performance under overvoltage conditions such as lightning."Trip-Free" Tripping and Delayed Action
Incorporates mechanisms to ensure safe manual and automatic disconnection under fault conditions, even if the actuator is held in the closed position.Compliance with Associated Connector Hardware
Specifies compatibility with EN 6113 connection and attachment kits, enabling standardization across installations.
Applications
prEN 2794-004 circuit breakers are specifically intended for:
Aerospace Onboard Electrical Systems
Including both main and peripheral circuit protection in fixed-wing and rotary aircraft.High-Reliability Environments
Sectors demanding robust operation under wide thermal variance and high mechanical stresses, such as avionics bays, power distribution units, and cockpit control panels.Panel Mount Installations
Use in environments requiring easy maintenance and clear identification, as these breakers utilize UNC-threaded terminals and follow standardized panel cut-out dimensions.Safety-Critical Circuits
Protection for systems where continuous functionality and clear fault disconnection are vital, e.g., communications, navigation, flight controls, and emergency equipment.
Related Standards
For comprehensive circuit breaker integration in aerospace systems, the following related European standards should be consulted:
EN 2350: Aerospace series - Circuit breakers - Technical specification
General technical requirements applicable to all aerospace circuit breakers.EN 2794-001: Aerospace series - Circuit breakers, single-pole, temperature compensated, rated currents 20 A to 50 A - Part 001: Technical specification
Overarching requirements and test methods referenced throughout prEN 2794-004.EN 3841-305: Aerospace series - Circuit breakers - Test methods - Part 305: Short-circuit performance
Defines short-circuit testing protocols vital for safety assurance.EN 6113: Aerospace series - Circuit breaker, connecting and attachment hardware
Specifies hardware kits compatible with the circuit breakers covered in this standard.TR 6083: Aerospace series - Cut-outs for installation of electrical components
Provides guidelines for standardized panel cut-outs.
Summary
prEN 2794-004 is dedicated to defining the product standard for temperature-compensated, single-pole aerospace circuit breakers with UNC thread terminals. It supports safe, reliable circuit protection in demanding aerospace environments, aligning with broader European requirements for electrical equipment and systems in aviation. Adhering to this standard ensures compatibility, safety, and performance across the aerospace industry.
Relations
- Effective Date
- 08-Jan-2025
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Frequently Asked Questions
prEN 2794-004 is a draft published by the European Committee for Standardization (CEN). Its full title is "Aerospace series - Circuit breakers, single-pole, temperature compensated, rated currents 20 A to 60 A - Part 004: UNC thread terminals - Product standard". This standard covers: This document specifies the characteristics of single-pole circuit breakers, temperature compensated with a rated current from 20 A to 25 A, used in aircraft on-board circuits at a temperature between −55 °C and 125 °C and at an altitude of 15 000 m max. These circuit breakers are operated by a push-pull type single push button (actuator), with delayed action “trip-free” tripping. They will continue to function up to the short-circuit current.
This document specifies the characteristics of single-pole circuit breakers, temperature compensated with a rated current from 20 A to 25 A, used in aircraft on-board circuits at a temperature between −55 °C and 125 °C and at an altitude of 15 000 m max. These circuit breakers are operated by a push-pull type single push button (actuator), with delayed action “trip-free” tripping. They will continue to function up to the short-circuit current.
prEN 2794-004 is classified under the following ICS (International Classification for Standards) categories: 49.060 - Aerospace electric equipment and systems. The ICS classification helps identify the subject area and facilitates finding related standards.
prEN 2794-004 has the following relationships with other standards: It is inter standard links to EN 2794-004:2014. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
prEN 2794-004 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2026
Aeronavtika - Odklopniki, enopolni, temperaturno kompenzirani, naznačeni tok od
20 A do 50 A - 004. del: Navojni priključki UNC - Standard za proizvod
Aerospace series - Circuit breakers, single-pole, temperature compensated, rated
currents 20 A to 60 A - Part 004: UNC thread terminals - Product standard
Luft- und Raumfahrt - Schutzschalter, einpolig, temperaturkompensiert, Nennströme von
20A bis 50A - Teil004: UNC-Klemmengewinde - Produktnorm
Série aérospatiale - Disjoncteurs unipolaires compensés en température, intensités
nominales 20 A à 50 A - Partie 004 : Bornes à filetage UNC - Norme de produit
Ta slovenski standard je istoveten z: prEN 2794-004
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.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2026
ICS 49.060 Will supersede EN 2794-004:2014
English Version
Aerospace series - Circuit breakers, single-pole,
temperature compensated, rated currents 20 A to 60 A -
Part 004: UNC thread terminals - Product standard
Série aérospatiale - Disjoncteurs unipolaires Luft- und Raumfahrt- Schutzschalter, einpolig,
compensés en température, intensités nominales 20 A temperaturkompensiert, Nennströme von 20A bis 50A-
à 50 A - Partie 004 : Bornes à filetage UNC - Norme de Teil004: UNC-Klemmengewinde- Produktnorm
produit
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 2794-004:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Dimensions and mass . 4
4.1 Dimensional characteristics . 4
4.2 Electrical diagram . 6
4.3 Mass . 6
4.4 Panel cut-out . 6
5 Characteristics . 6
5.1 Material, surface treatment . 6
5.2 Mechanical characteristics . 6
5.2.1 Fasteners . 6
5.2.2 Recommended tightening torque of attaching nut for installation . 6
5.2.3 Recommended tightening torque of connection hardware for installation . 6
5.2.4 Resistance to vibrations . 7
5.2.5 Resistance to shocks . 7
5.2.6 Mechanical endurance . 7
5.3 Environment characteristics . 7
5.3.1 Humidity . 7
5.3.2 Corrosion . 7
5.3.3 Contaminating liquids . 7
5.3.4 Overvoltage caused by lightning . 7
5.4 Electrical characteristics . 7
5.4.1 Nominal voltage of operational circuits . 7
5.4.2 Voltage drop at Ι . 8
n
5.4.3 Minimum and maximum tripping thresholds . 8
5.4.4 Overload trip . 8
5.4.5 Short-circuit values . 8
5.4.6 No-Load and load endurance . 9
5.4.7 Dielectric rigidity . 9
5.4.8 Insulation resistance . 10
6 Designation . 10
7 Rated current code . 10
8 Delivery hardware code . 11
9 Marking . 11
10 Technical specification . 11
Bibliography . 12
European foreword
This document (prEN 2794-004:2026) 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 pr
...