SIST EN 50171:2022/oprA1:2026
(Amendment)Central safety power supply systems
General Information
- Abstract
This document specifies the general requirements for central power supply systems for an independent energy supply to essential safety equipment. This standard covers systems that are permanently connected to AC supply voltages not exceeding 1 000 V and use batteries as an alternative power source.
Central safety power supply systems are intended to ensure energy supply to emergency escape lighting in the event of normal supply failure and may be suitable for energizing other essential safety equipment, for example:
– electric circuits of automatic fire extinguishing installations;
– paging systems and signalling safety installations;
– smoke extraction equipment;
– carbon monoxide warning systems;
– special safety installations related to specific buildings, e.g. high-risk areas.
The power supply of CPS systems should be dedicated only to the essential safety equipment, and not for other type of loads such as general purpose IT or industrial systems etc.
Combinations of the aforementioned safety equipment types are permitted together on the same central safety power supply system providing the availability for safety equipment loads is not impaired. A fault occurring in a circuit should not cause the interruption in any other circuit used to supply essential safety equipment.
Schematic representations of typical central safety power supply equipment are depicted in Clause 4.
Power supply systems for fire alarm equipment that are covered by EN 54 (series) are excluded.
- Status
- Not Published
- Public Enquiry End Date
- 30-Jul-2026
- Technical Committee
- MOV - Measuring equipment for electromagnetic quantities
- Current Stage
- 4020 - Public enquire (PE) (Adopted Project)
- Start Date
- 26-May-2026
- Due Date
- 13-Oct-2026
- Completion Date
- 24-Sep-2026
Overview
SIST EN 50171:2022/oprA1:2026 sets out the general requirements for central safety power supply systems (CPS) intended to provide independent energy to essential safety equipment. This standard is maintained by SIST and aligns with European standards for safety and reliability in emergency situations. It covers power systems permanently connected to AC supply voltages up to 1,000 V, utilizing batteries as an alternative power source. The document emphasizes the role of central safety power supply systems in ensuring continued operation of critical safety installations, especially during regular mains power failures.
Key Topics
Central safety power supply systems play a fundamental role in safeguarding occupants and property by supporting essential safety equipment in the event of a power outage. Key aspects covered in SIST EN 50171:2022/oprA1:2026 include:
- System Scope: CPS must only supply essential safety equipment - such as emergency escape lighting, fire extinguishing systems, smoke extraction, and signaling safety installations - and cannot be used for general-purpose loads.
- Changeover Modes: The standard describes several operational modes for switching between main and backup power, with emphasis on maintaining uninterrupted supply and ensuring isolation of faults to prevent wider system outages.
- Battery Requirements: Guidance on battery deep discharge protection, design life expectancy (minimum 10 years at 20°C ambient temperature), charging, and monitoring is specified to maximize reliability and minimize maintenance issues.
- Electromagnetic Compatibility (EMC): CPS must comply with relevant EMC requirements for residential, commercial, and industrial environments to minimize risk of interference, as detailed in referenced EN IEC 61000 and EN IEC 62040 standards.
- Testing and Inspection: Requirements are included for automatic and manual test units, system readiness indications, and periodic status monitoring to ensure ongoing operational integrity.
Applications
Central safety power supply systems specified by this standard are found in environments where continuous operation of safety-related equipment is critical:
- Emergency Escape Lighting: Ensures safe evacuation routes during power loss.
- Fire Protection Systems: Supplies electric circuits for automatic fire extinguishing installations.
- Communication and Warning Devices: Powers paging systems, carbon monoxide warning systems, and safety signaling in public or high-risk areas.
- Smoke Extraction Equipment: Supports ventilation and smoke control during emergencies.
- Special Safety Installations: Used in high-risk environments, such as hospitals, airports, laboratories, and commercial buildings, where power continuity to safety equipment is legally required.
- Versatile Locations: Applicable to residential, commercial, light-industrial, and heavy industrial locations, with tailored EMC requirements for each use case.
Related Standards
The SIST EN 50171:2022/oprA1:2026 standard references and builds on several international and European standards to ensure comprehensive and harmonized safety practices:
- EN IEC 62040-1: Uninterruptible power systems (UPS) - Safety requirements.
- EN IEC 62040-2: UPS - Electromagnetic compatibility requirements.
- EN IEC 61000-6-2, -6-3, -6-4, -6-8: Electromagnetic compatibility - Generic standards for immunity and emissions in various installation environments.
- EN 54 Series: Fire alarm system power supply requirements (explicitly excluded from the CPS scope in this standard).
By ensuring compliance with SIST EN 50171 and its referenced standards, facility managers, system integrators, and safety engineers can guarantee robust and effective emergency power supply solutions in line with recognized European best practices. This contributes to greater resilience, safety, and peace of mind for building occupants and operators.
Relations
- Effective Date
- 15-Oct-2024
- Effective Date
- 15-Oct-2024
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Frequently Asked Questions
SIST EN 50171:2022/oprA1:2026 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Central safety power supply systems". This standard covers: This document specifies the general requirements for central power supply systems for an independent energy supply to essential safety equipment. This standard covers systems that are permanently connected to AC supply voltages not exceeding 1 000 V and use batteries as an alternative power source. Central safety power supply systems are intended to ensure energy supply to emergency escape lighting in the event of normal supply failure and may be suitable for energizing other essential safety equipment, for example: – electric circuits of automatic fire extinguishing installations; – paging systems and signalling safety installations; – smoke extraction equipment; – carbon monoxide warning systems; – special safety installations related to specific buildings, e.g. high-risk areas. The power supply of CPS systems should be dedicated only to the essential safety equipment, and not for other type of loads such as general purpose IT or industrial systems etc. Combinations of the aforementioned safety equipment types are permitted together on the same central safety power supply system providing the availability for safety equipment loads is not impaired. A fault occurring in a circuit should not cause the interruption in any other circuit used to supply essential safety equipment. Schematic representations of typical central safety power supply equipment are depicted in Clause 4. Power supply systems for fire alarm equipment that are covered by EN 54 (series) are excluded.
This document specifies the general requirements for central power supply systems for an independent energy supply to essential safety equipment. This standard covers systems that are permanently connected to AC supply voltages not exceeding 1 000 V and use batteries as an alternative power source. Central safety power supply systems are intended to ensure energy supply to emergency escape lighting in the event of normal supply failure and may be suitable for energizing other essential safety equipment, for example: – electric circuits of automatic fire extinguishing installations; – paging systems and signalling safety installations; – smoke extraction equipment; – carbon monoxide warning systems; – special safety installations related to specific buildings, e.g. high-risk areas. The power supply of CPS systems should be dedicated only to the essential safety equipment, and not for other type of loads such as general purpose IT or industrial systems etc. Combinations of the aforementioned safety equipment types are permitted together on the same central safety power supply system providing the availability for safety equipment loads is not impaired. A fault occurring in a circuit should not cause the interruption in any other circuit used to supply essential safety equipment. Schematic representations of typical central safety power supply equipment are depicted in Clause 4. Power supply systems for fire alarm equipment that are covered by EN 54 (series) are excluded.
SIST EN 50171:2022/oprA1:2026 is classified under the following ICS (International Classification for Standards) categories: 29.200 - Rectifiers. Convertors. Stabilized power supply; 29.240 - Power transmission and distribution networks. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 50171:2022/oprA1:2026 has the following relationships with other standards: It is inter standard links to SIST EN 50171:2022, SIST EN 50171:2022/AC:2024. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
SIST EN 50171:2022/oprA1:2026 is associated with the following European legislation: EU Directives/Regulations: 2014/30/EU, 2014/35/EU; Standardization Mandates: M/511, M/552. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
SIST EN 50171:2022/oprA1:2026 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-julij-2026
Centralni varnostni napajalni sistemi
Central safety power supply systems
Zentrale Sicherheitsstromversorgungssysteme
Systèmes d'alimentation de sécurité à source centrale
Ta slovenski standard je istoveten z: EN 50171:2021/prA1:2026
ICS:
29.200 Usmerniki. Pretvorniki. Rectifiers. Convertors.
Stabilizirano električno Stabilized power supply
napajanje
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
NORME EUROPÉENNE PROJET
EN 50171:2021
EUROPÄISCHE NORM
EUROPEAN STANDARD
prA1
Juillet 2026
ICS 29.240 -
Version française
Systèmes d'alimentation de sécurité à source centrale
Zentrale Sicherheitsstromversorgungssysteme Central safety power supply systems
Ce projet d'amendement prA1, s'il est approuvé, modifiera la Norme Européenne EN 50171:2021; il est soumis aux membres du CENELEC
pour enquête.
Date limite du CENELEC: 2026-10-16.
Il a été établi par le CLC/TC 22X.
Si ce projet devient un amendement, les membres du CENELEC sont tenus de se soumettre au Règlement Intérieur du CEN/CENELEC,
qui définit les conditions dans lesquelles doit être attribué, sans modification, le statut de norme nationale à cet amendement.
Le présent projet d'amendement a été établi par le CENELEC en trois versions officielles (allemand, anglais, français).
Une version dans une autre langue faite par traduction sous la responsabilité d'un membre du CENELEC dans sa langue nationale, et
notifiée au CEN-CENELEC Management Centre, a le même statut que les versions officielles.
Les membres du CENELEC sont les comités électrotechniques nationaux des pays suivants: Allemagne, Autriche, Belgique, Bulgarie,
Chypre, Croatie, Danemark, Espagne, Estonie, Finlande, France, Grèce, Hongrie, Irlande, Islande, Italie, Lettonie, Lituanie, Luxembourg,
Malte, Norvège, Pays-Bas, Pologne, Portugal, République de Macédoine du Nord, République de Serbie, République Tchèque, Roumanie,
Royaume-Uni, Slovaquie, Slovénie, Suède, Suisse et Turquie.
Les destinataires du présent projet sont invités à présenter, avec leurs observations, notifications des droits de propriété dont ils auraient
éventuellement connaissance et à fournir une documentation explicative.
Avertissement: Le présent document n'est pas une Norme Européenne. Il est diffusé pour examen et observations. Il est susceptible de
modification sans préavis et ne doit pas être cité comme Norme Européenne.
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
European Committee for Electrotechnical Standardization
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Bruxelles
© 2026 CENELEC Tous droits d'exploitation sous quelque forme et de quelque manière que ce soit réservés dans le monde entier aux
membres du CENELEC.
Project: 80778 Réf. n° EN 50171:2021/prA1:2026 F
Contents Page
1 European foreword . 3
2 1 Modification to Clause 1, “Scope” . 4
3 2 Modification to Clause 2, “Normative references” . 4
4 3 Modification to Clause 3, “Terms and definitions” . 4
5 4 Modification to 4.2, “Changeover mode” . 5
6 5 Modification to 4.3, “Mode without interruption” . 6
7 6 Modification to 4.4, “Changeover mode with an additional control switching device for
8 central switching of the load” . 6
9 7 Modification to 4.5, “Changeover mode with an additional control switching device for
10 partial switching of the load “ . 6
11 8 Modification to 4.6, “Non-maintained changeover mode” . 7
12 9 Modification to 4.7, “Mode without interruption with an additional control switching device
13 for central switching of the load” . 7
14 10 Modification to 5.1, “Normal operating conditions and requirements for central safety
15 power supply systems” . 7
16 11 Modification to 5.2, “Requirements to be specified by the user” . 8
17 12 Modification to 6.1, “General requirements” . 8
18 13 Modification to 6.3.1, “Battery charges and rectifiers” . 8
19 14 Modification to 6.5.4 . 8
20 15 Modification to 6.6.8 . 8
21 16 Modification to 6.6.11 . 8
22 17 Modification to 6.7 “Deep discharge protection” . 8
23 18 Modification to 6.8.1 . 9
24 19 Modification to 6.8.2 . 9
25 20 Modification to 6.8.4 . 9
26 21 Modification to 6.12.1 . 9
27 22 Modification to 6.12.4 . 9
28 23 Modification to 6.13.2 . 9
29 24 Modification to 6.13.4 . 9
30 European foreword
31 This document (EN 50171:2021/prA1:2026) has been prepared by CLC/TC 22X “Power electronics”.
32 This document is currently submitted to the Enquiry.
33 The following dates are proposed:
• latest date by which the existence of this (doa) dav + 6 months
document has to be announced at national level
• latest date by which this document has to be (dop) dav + 12 months
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) dav + 36 months
conflicting with this document have to be (to be confirmed or
withdrawn modified when voting)
35 1 Modification to Clause 1, “Scope”
nd
36 In the 4th paragraph, 2 sentence, replace “the interruption” with “a failure”.
37 2 Modification to Clause 2, “Normative references”
38 Replace the references to EN 62040-1, EN 61000-6-2, EN 61000-6-3 and EN 61000-6-4 with the following,
39 respectively:
40 EN IEC 62040-1, Uninterruptible power systems (UPS) - Part 1: Safety requirements (IEC 62040-1)
41 EN IEC 61000-6-2, Electromagnetic compatibility (EMC) - Part 6-2: Generic standards - Immunity standard for
42 industrial environments (IEC 61000-6-2)
43 EN IEC 61000-6-3, Electromagnetic compatibility (EMC) - Part 6-3: Generic standards - Emission standard for
44 equipment in residential locations (IEC 61000-6-3)
45 EN IEC 61000-6-4, Electromagnetic compatibility (EMC) - Part 6-4: Generic standards - Emission standard for
46 industrial environments (IEC 61000-6-4)
47 Add the following references:
48 EN IEC 61000-6-8:2020, Electromagnetic compatibility (EMC) - Part 6-8: Generic standards - Emission
49 standard for professional equipment in commercial and light-industrial locations
50 EN IEC 62040-2, Uninterruptible power systems (UPS) - Part 2: Electromagnetic compatibility (EMC)
51 requirements
52 3 Modification to Clause 3, “Terms and definitions”
53 Add the 3 following definitions:
54 3.24
55 residential location
56 area of land designated for domestic dwellings where the mains pow
...