Power capacitors - Low-voltage power factor correction banks

Applicable to low-voltage a.c. capacitor banks intended to be used for power factor correction purposes, equipped with a built-in switchgear and controlgear apparatus capable of connecting to or disconnecting from the mains part(s) of the bank with the aim to correct its power factor.

Kondensatorbatterien zur Korrektur des Niederspannungsleistungsfaktors

Condensateurs de puissance - Batteries de compensation du facteur de puissance basse tension

S'applique aux batteries de condensateurs à basse tension en courant alternatif destinées à la compensation du facteur de puissance. Ces batteries comportent des appareillages de connexion et de commande intégrés capables de mettre sous tension ou hors tension des fractions de l'ensemble afin de compenser le facteur de puissance du réseau.

Power capacitors - Low-voltage power factor correction banks

General Information

Status
Published
Publication Date
30-Sep-2003
ICS
31.060.70 - Power capacitors
Technical Committee
SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Oct-2003
Due Date
01-Oct-2003
Completion Date
01-Oct-2003
Directive
2006/95/EC - Directive 2006/95/EC of the European Parliament and of the Council of 12 December 2006 on the harmonisation of the laws of Member States relating to electrical equipment designed for use within certain voltage limits (codified version)
2014/35/EU - Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limits
73/23/EEC - Electrical equipment designed for use within certain voltage limits
Ref Project
EN 61921:2003 - Power capacitors - Low-voltage power factor correction banks

Relations

Replaced By
SIST EN IEC 61921:2025 - Power capacitors - Low-voltage power factor correction banks (IEC 61921:2017)
Effective Date
01-Oct-2025

Overview

EN 61921:2003 (CLC adoption of IEC 61921:2003) specifies requirements for low-voltage a.c. capacitor banks intended for power factor correction. It applies to capacitor banks that include built-in switchgear and controlgear capable of automatically or manually connecting/disconnecting sections of the bank to correct the mains power factor. This European Standard was approved by CENELEC in 2003 and incorporates normative and informative annexes (A, B, ZA normative; C, D informative).

Key topics and requirements

EN 61921 addresses the essential aspects of low-voltage power factor correction banks, focusing on safe, reliable operation and conformity with electrotechnical practice. Key technical topics include:

  • Scope and definitions for low-voltage power factor correction banks and associated components.
  • Design and construction considerations for capacitor banks with integrated switchgear and controlgear.
  • Performance, rating and testing principles applicable to bank components (consistent with referenced capacitor standards).
  • Safety and protection requirements for live parts, enclosure integrity and user access (including guidance where unskilled persons may access distribution equipment).
  • Switching and control functions needed to connect/disconnect capacitor elements to correct power factor.
  • Electromagnetic compatibility (EMC) and immunity) considerations relevant to power-electronic switching and mains interaction.
  • Normative and informative annexes (including Annex ZA mapping to European normative references).

Note: EN 61921 references and aligns with related IEC/EN standards for capacitors, low-voltage switchgear and EMC testing rather than duplicating their detailed test methods.

Applications

EN 61921 is directly applicable to:

  • Stationary low-voltage capacitor banks used in commercial, industrial and utility installations for reactive power compensation.
  • Integrated units with built-in switchgear/controlgear for automatic or manual power factor correction. Practical uses include reducing reactive power charges, improving voltage regulation, decreasing losses in distribution systems, and supporting compliance with utility power factor requirements.

Who should use this standard

  • Manufacturers of power capacitor banks and integrated switchgear assemblies
  • Electrical designers and consultants specifying reactive compensation systems
  • Installers and commissioning engineers responsible for safe installation and testing
  • Testing laboratories and conformity assessment bodies performing type and routine tests
  • Utilities and facility managers evaluating equipment for compliance and performance

Related standards

EN 61921 is endorsed as the European adoption of IEC 61921:2003 and cross-references several standards such as:

  • EN/IEC 60831 and EN/IEC 60931 (shunt power capacitor requirements)
  • EN/IEC 60439 series (low-voltage switchgear and controlgear assemblies)
  • EN/IEC 61000 series (EMC and immunity test guidance)

Keywords: EN 61921, power capacitors, low-voltage power factor correction banks, capacitor banks, switchgear, controlgear, CLC, IEC 61921.

Frequently Asked Questions

SIST EN 61921:2003 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Power capacitors - Low-voltage power factor correction banks". This standard covers: Applicable to low-voltage a.c. capacitor banks intended to be used for power factor correction purposes, equipped with a built-in switchgear and controlgear apparatus capable of connecting to or disconnecting from the mains part(s) of the bank with the aim to correct its power factor.

Applicable to low-voltage a.c. capacitor banks intended to be used for power factor correction purposes, equipped with a built-in switchgear and controlgear apparatus capable of connecting to or disconnecting from the mains part(s) of the bank with the aim to correct its power factor.

SIST EN 61921:2003 is classified under the following ICS (International Classification for Standards) categories: 31.060.70 - Power capacitors. The ICS classification helps identify the subject area and facilitates finding related standards.

SIST EN 61921:2003 has the following relationships with other standards: It is inter standard links to SIST EN IEC 61921:2025. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

SIST EN 61921:2003 is associated with the following European legislation: EU Directives/Regulations: 2006/95/EC, 2014/35/EU, 73/23/EEC. 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 61921:2003 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 SIST EN 61921:2003
STANDARD
oktober 2003
Power capacitors - Low-voltage power factor correction banks
ICS 31.060.70 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 61921
NORME EUROPÉENNE
EUROPÄISCHE NORM July 2003
ICS 31.060.70
English version
Power capacitors –
Low-voltage power factor correction banks
(IEC 61921:2003)
Condensateurs de puissance -  Kondensatorbatterien zur Korrektur
Batteries de compensation des Niederspannungsleistungsfaktors
du facteur de puissance basse tension (IEC 61921:2003)
(CEI 61921:2003)
This European Standard was approved by CENELEC on 2003-06-01. CENELEC 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 CENELEC 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 CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61921:2003 E
Foreword
The text of document 33/387/FDIS, future edition 1 of IEC 61921, prepared by IEC TC 33, Power
capacitors, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 61921 on 2003-06-01.
The following dates were fixed:

– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2004-03-01

– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-06-01

Annexe
...

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