IEC 62933-5-2:2020

Electrical energy storage (EES) systems - Part 5-2: Safety requirements for grid-integrated EES systems - Electrochemical-based systems

IEC 62933-5-2:2020 primarily describes safety aspects for people and, where appropriate, safety matters related to the surroundings and living beings for grid-connected energy storage systems where an electrochemical storage subsystem is used.

Systèmes de stockage de l'énergie électrique (EES) - Partie 5-2: Exigences de sécurité pour les systèmes EES intégrés dans un réseau - Systèmes électrochimiques

L’IEC 62933-5-2:2020 décrit principalement les aspects liés à la sécurité des personnes et, le cas échéant, les questions de sécurité associées à l’environnement et aux êtres vivants pour les systèmes de stockage de l’énergie raccordés à un réseau qui utilisent un sous-système électrochimique de stockage.

General Information

• Status: Published
• Publication Date: 15-Apr-2020
• ICS: 13.020.30 - Environmental impact assessment
• ICS: 31.080.01 - Semiconductor devices in general
• Technical Committee: TC 120 - Electrical Energy Storage (EES) systems
• Drafting Committee: WG 5 - TC 120/WG 5
• Current Stage: PPUB - Publication issued
• Start Date: 16-Apr-2020
• Completion Date: 08-May-2020

Relations

• Revised: IEC 62933-5-2:2025 - Electrical energy storage (EES) systems - Part 5-2: Safety requirements for grid-integrated EES systems - Electrochemical-based systems
• Effective Date: 05-Sep-2023

Overview

IEC 62933-5-2:2020 is an international standard developed by the International Electrotechnical Commission (IEC) to define the safety requirements for grid-integrated electrical energy storage (EES) systems, specifically focusing on electrochemical-based systems. This standard addresses critical safety aspects concerning people, surrounding environments, and living beings when deploying battery energy storage systems (BESS) connected to electrical grids.

The document provides comprehensive guidelines for design, risk assessment, operation, maintenance, and life cycle safety management of electrochemical storage subsystems in grid-connected EES. Its framework supports minimizing hazards related to electrical, mechanical, fire, chemical, and environmental risks.

Key Topics

• Scope and Definitions: Clarifies fundamental terms and scope, focusing on the safety of electrochemical-based grid-connected EES systems.
• Risk Assessment: Procedures to identify, analyze, and evaluate hazards specific to BESS, including electrical, fire, chemical, and physical risks.
• System Design Safety: Emphasizes preventive measures such as inherently safe design principles protecting against:
  • Electrical hazards
  • Mechanical hazards
  • Explosion risks
  • Fire and temperature hazards
  • Chemical effects and toxic substances
  • Malfunctions in auxiliary, control, and communication systems
• Safety Measures: Requirements for overcurrent protection, system disconnection, shutdown protocols, guards, and protective devices.
• Life Cycle Management: Guidelines to ensure safety throughout the system’s operational life, including:
  • Operation and maintenance practices
  • Staff training and competence
  • Partial system updates and design revisions
  • End-of-service-life safety management
• Validation and Testing: Specifies methods for safety validation under normal and abnormal conditions covering electrical, mechanical, environmental, and fire hazards.
• Informative Annexes:
  • Ownership models for BESS
  • Hazard and risk details relevant to different battery technologies like lithium-ion, lead-acid, nickel batteries, solid-state batteries, and flow batteries
  • Large-scale fire testing procedures
  • Environmental protection test methods
  • Safety signage for risk communication

Applications

IEC 62933-5-2:2020 is essential for manufacturers, engineers, and safety professionals involved with:

• Grid-Integrated Battery Energy Storage Systems, ensuring compliance with internationally recognized safety norms.
• Design and Engineering of electrochemical EES systems for utility-scale and commercial energy projects.
• Operational Safety Management, including site managers, maintenance teams, and operational staff to mitigate risks through proper controls and training.
• Equipment Certification and Testing Bodies who validate performance and safety compliance of energy storage systems.
• Regulatory Authorities and Standards Developers, supporting harmonized safety regulations and policies worldwide.

This standard drives safer deployment and operation of energy storage technologies critical for modern power grids incorporating renewable energy and distributed energy resources.

Related Standards

• IEC 62933 Series: Comprehensive standards for electrical energy storage systems covering general requirements and various technology-specific parts.
• IEC 61000 Series: Electromagnetic compatibility standards relevant to EES control and communication systems.
• IEC 62133: Safety requirements for portable sealed secondary cells, relevant for small-scale battery technologies.
• UL 9540: Standard for energy storage system and equipment safety, commonly applied in North America.
• ISO 45001: Occupational health and safety management, complementing operational safety practices.
• NFPA 855: Standard for the installation of stationary energy storage systems, covering fire protection guidelines.

By adhering to IEC 62933-5-2:2020, stakeholders ensure robust safety frameworks that reduce risks related to electrochemical energy storage integration into electrical grids, fostering reliable and sustainable energy infrastructures globally.

Standards Content (Sample)

IEC 62933-5-2 ®
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electrical energy storage (EES) systems –
Part 5-2: Safety requirements for grid-integrated EES systems –
Electrochemical-based systems
Systèmes de stockage de l'énergie électrique (EES) –
Partie 5-2: Exigences de sécurité pour les systèmes EES intégrés dans un
réseau – Systèmes électrochimiques

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IEC 62933-5-2 ®
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electrical energy storage (EES) systems –

Part 5-2: Safety requirements for grid-integrated EES systems –

Electrochemical-based systems
Systèmes de stockage de l'énergie électrique (EES) –

Partie 5-2: Exigences de sécurité pour les systèmes EES intégrés dans un

réseau – Systèmes électrochimiques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.020.30 ISBN 978-2-8322-8146-8

– 2 – IEC 62933-5-2:2020 © IEC 2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Basic guidelines for safety of BESS . 11
4.1 General . 11
4.2 Approach to BESS safety . 12
4.3 BESS changes in ownership, control or use . 14
5 Hazard considerations . 14
6 BESS system risk assessment . 15
6.1 BESS structure . 15
6.1.1 General characteristics . 15
6.1.2 Specific characteristics . 16
6.2 Description of BESS conditions . 16
6.3 Risk analysis . 16
6.3.1 General . 16
6.3.2 Hazard identification specific to BESS . 17
6.3.3 Risk consideration . 17
6.3.4 System level risk analysis . 17
6.4 System level risk assessment . 17
7 Requirements necessary to reduce risks . 17
7.1 General measures to reduce risks . 17
7.2 Preventive measures against damage to neighbouring inhabitants . 18
7.3 Preventive measures against physical injury or damage to the health of
workers and residents . 18
7.4 Overcurrent protection design . 18
7.5 BESS disconnection and shutdown . 18
7.6 Operation and maintenance . 18
7.7 Staff training . 18
7.8 Safety design . 19
7.9 General requirements for BESS safety . 19
7.10 Inherently safe design of BESS . 19
7.10.1 Protection from electrical hazards . 19
7.10.2 Protection from mechanical hazards . 20
7.10.3 Protection from explosion . 21
7.10.4 Protection from hazards arising from electric, magnetic, and
electromagnetic fields . 21
7.10.5 Protection from fire hazards . 21
7.10.6 Protection from temperature hazards . 21
7.10.7 Protection from chemical effects . 22
7.10.8 Protection from hazards arising from auxiliary, control and
communication system malfunctions . 22
7.10.9 Protection from hazards arising from environments. 22
7.11 Guards and protective measures. 23
7.11.1 General . 23
7.11.2 BESS disconnection and shutdown . 23

7.11.3 Other guards and protective functions of BESS . 24
7.12 Information for end users . 28
7.13 Life cycle safety management . 28
7.13.1 Operation and maintenance . 28
7.13.2 Partial system change . 31
7.13.3 Design revision . 32
7.13.4 End of service life management . 33
7.13.5 Measures for validating life cycle safety management . 33
8 System validation and testing . 33
8.1 General . 33
8.2 Validation and testing of BESS . 36
8.2.1 Electrical hazards . 36
8.2.2 Mechanical hazards . 38
8.2.3 Explosion . 38
8.2.4 Hazards arising from electric, magnetic, and electromagnetic fields . 39
8.2.5 Fire hazards (propagation) . 39
8.2.6 Temperature hazards. 40
8.2.7 Chemical effects . 41
8.2.8 Hazards arising from auxiliary, control and communication system
malfunctions . 42
8.2.9 Hazards arising from environments . 42
8.2.10 IP rating of BESS enclosure and protective guards . 43
9 Guidelines and manuals . 43
Annex A (informative) Ownership models of BESS . 44
Annex B (informative) BESS hazards and risks . 45
B.1 General introduction . 45
B.2 Hazard concerns . 51
B.2.1 General . 51
B.2.2 Fire hazards . 51
B.2.3 Chemical hazards . 51
B.2.4 Electrical hazards . 51
B.2.5 Energy hazards . 52
B.2.6 Physical hazards . 52
B.2.7 High-pressure hazards . 52
B.3 Hazard considerations under normal operating conditions . 52
B.3.1 Fire and explosive hazards . 52
B.3.2 Chemical hazards . 52
B.3.3 Electrical hazards . 53
B.3.4 Physical hazards . 53
B.4 Hazard considerations under emergency/abnormal conditions . 54
B.4.1 Fire hazards . 54
B.4.2 Chemical hazards . 54
B.4.3 Electrical hazards . 55
B.4.4 Physical hazards . 56
B.5 Commercially available battery technologies . 56
B.5.1 Lithium ion (Li-ion) batteries (C-A) . 56
B.5.2 Lead-acid batteries (C-B) . 57
B.5.3 Nickel batteries (C-B) . 58
B.5.4 High-temperature sodium batteries (C-C). 60

– 4 – IEC 62933-5-2:2020 © IEC 2020
B.5.5 Flow batteries (C-D) . 61
B.5.6 Lithium metal solid state batteries (C-Z) . 63
B.6 Other technologies . 63
Annex C (informative) Large-scale fire testing on BESS . 64
Annex D (informative) Test methods for protection from hazards arising from
environments . 65
D.1 General . 65
D.2 Outdoor installations subject to moisture exposure . 65
D.3 Outdoor installation near marine environments . 65
Annex E (informative)  Information for validation of BESS life cycle safety
management . 66
E.1 Overview . 66
E.2 General introduction . 66
E.3 Operation and maintenance process . 66
E.4 Preventive maintenance . 66
E.5 Measuring and monitoring of system soundness . 67
E.6 Staff training . 67
E.7 Partial system change . 67
E.8 Design revision . 67
Annex F (informative) BESS safety signage . 68
Annex G (informative) Example of testing for verification of thermal control operation . 69
Bibliography . 70

Figure 1 – General description for risk assessment and reduction of BESS . 11
Figure 2 – An example of BESS architecture. 15
Figure 3 – Example of isolated condition (whole isolation of BESS) . 24
Figure 4 – Incompatibility of capacity and/or usage in a BESS . 32

Table 1 – BESS categories . 13
Table 2 – Examples of BESS use. 14
Table 3 – Examples of components within subsystems of a BESS . 16
Table 4 – Examples of incompatibilities that can arise from system changes . 32
Table 5 – Overview of validation and testing for BESS . 35
Table B.1 – Hazards of BESS in common . 47
Table B.2 – Hazards of BESS using non-aqueous electrolyte battery (category "C-A") . 48
Table B.3 – Hazards of BESS using aqueous electrolyte battery (category "C-B") . 49
Table B.4 – Hazards of BESS using high temperature battery (category "C-C") . 50
Table B.5 – Hazards of BESS using flow battery (category "C-D") . 51

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL ENERGY STORAGE (EES) SYSTEMS –

Part 5-2: Safety requirements for grid-integrated EES systems –
Electrochemical-based systems
FOREWORD
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International Standard IEC 62933-5-2 has been prepared by IEC technical committee 120:
Electrical Energy Storage (EES) Systems.
This International Standard is to be used in conjunction with IEC TS 62933-5-1:2017.
The text of this International Standard is based on the following documents:
FDIS Report on voting
120/173/FDIS 120/182/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – IEC 62933-5-2:2020 © IEC 2020
A list of all parts in the IEC 62933 series, published under the general title Electrical energy
storage (EES) systems, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
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the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
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INTRODUCTION
All the electrical energy storage systems (EESS) follow the general safety requirements as
described in IEC TS 62933-5-1, which is based on a systems approach. IEC 62933-5-2 follows
the same structure as IEC TS 62933-5-1 and provides additional requirements for battery
energy storage systems (BESS). The additional requirements are provided for the following
reasons:
a) BESS can be integrated into a significant range of electrical grids.
b) The level of safety requirements awareness can vary between utilities, system integrators,
operators and end-users.
c) Although the safety of individual subsystems is generally covered by international standards
at ISO and IEC levels, the safety matters that arise due to the combination of
electrochemical accumulation subsystems and any electrical subsystems are not always
considered. BESS are complex at the systems level due to the variety of potential battery
options and configurations, including the combination of subsystems (e.g. control systems
for electrochemical accumulation subsystems, electrochemical accumulation subsystems,
power conversion subsystems and auxiliary subsystems). Compliance with standards and
related material produced specifically for the safety of subsystems cannot be sufficient to
reach an acceptable level of safety for the overall system.
d) BESS can have additional safety hazards, due, for example, to the presence of chemicals,
the emission of toxic gases, chemicals spilt around the electrochemical accumulation
subsystems and to events critical for safety from electrochemical accumulation subsystems
that cause safety issues for the entire BESS. They can cause loss of power at any part of
the systems and buildings that can result in additional threats to safety. From a systems
perspective, these individual hazards can have a system wide impact.

– 8 – IEC 62933-5-2:2020 © IEC 2020
ELECTRICAL ENERGY STORAGE (EES) SYSTEMS –

Part 5-2: Safety requirements for grid-integrated EES systems –
Electrochemical-based systems
1 Scope
This part of IEC 62933 primarily describes safety aspects for people and, where appropriate,
safety matters related to the surroundings and living beings for grid-connected energy storage
systems where an electrochemical storage subsystem is used.
This safety standard is applicable to the entire life cycle of BESS (from design to end of service
life management).
This document provides further safety provisions that arise due to the use of an electrochemical
storage subsystem (e.g. battery system) in energy storage systems that are beyond the general
safety considerations described in IEC TS 62933-5-1.
This document specifies the safety requirements of an “electrochemical” energy storage system
as a "system" to reduce the risk of harm or damage caused by the hazards of an electrochemical
energy storage system due to interactions between the subsystems as presently understood.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitute 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.
IEC 60068-2-52, Environmental testing – Part 2-52: Tests – Test Kb: Salt mist, cyclic (sodium
chloride solution)
IEC 60079-7:2015, Explosive atmospheres – Part 7: Equipment protection by increased safety
"e"
IEC 60079-7:2015/AMD1:2017
IEC 60079-13, Explosive atmospheres – Part 13: Equipment protection by pressurized room "p"
and artificially ventilated room "v"
IEC 60079-29 (all parts), Explosive atmospheres – Gas detectors
IEC 60364 (all parts), Low-voltage electrical installations
IEC 60364-4-44, Low-voltage electrical installations – Part 4-44: Protection for safety –
Protection against voltage disturbances and electromagnetic disturbances
IEC 60364-6:2016, Low voltage electrical installations – Part 6: Verification
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests

IEC 60812, Failure modes and effects analysis (FMEA and FMECA)
IEC 61000-1-2, Electromagnetic compatibility (EMC) – Part 1-2: General – Methodology for the
achievement of functional safety of electrical and electronic systems including equipment with
regard to electromagnetic phenomena
IEC 61000-6-7, Electromagnetic compatibility (EMC) – Part 6-7: Generic standards – Immunity
requirements for equipment intended to perform functions in a safety-related system (functional
safety) in industrial locations
IEC 61025, Fault tree analysis (FTA)
IEC 61660-1, Short-circuit currents in d.c. auxiliary installations in power plants and substations
– Part 1: Calculation of short-circuit currents
IEC 61660-2, Short-circuit currents in d.c. auxiliary installations in power plants and substations
– Part 2: Calculation of effects
IEC 61882, Hazard and operability studies (HAZOP studies) – Application guide
IEC 61936-1:2010, Power installations exceeding 1 kV a.c. – Part 1: Common rules
IEC 61936-1:2010/AMD1:2014
IEC 62305-2, Protection against lightning – Part 2: Risk management
IEC 62368-1, Audio/video, information and communication technology equipment – Part 1:
Safety requirements
IEC 62477-1:2012, Safety requirements for power electronic converter systems and equipment
– Part 1: General
IEC 62477-1:2012/AMD1:2016
IEC 62485-2, Safety requirements for secondary batteries and battery installations – Part 2:
Stationary batteries
IEC 62619:2017, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements for secondary lithium cells and batteries, for use in industrial
applications
IEC 62933-1, Electrical energy storage (EES) systems – Part 1: Vocabulary
IEC TS 62933-5-1:2017, Electrical energy storage (EES) systems – Part 5-1: Safety
considerations for grid integrated EES systems – General specification
ISO/IEC Guide 51:2014, Safety aspects – Guidelines for their inclusion in standards
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62933-1,
IEC TS 62933-5-1 and the following apply.

– 10 – IEC 62933-5-2:2020 © IEC 2020
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
NOTE Where differences in definitions appearing in IEC 62933-1 and IEC TS 62933-5-1 exist, the definition given
in IEC 62933-1 prevails, unless otherwise specified here.
3.1
battery energy storage system
BESS
electrical energy storage system with accumulation subsystem based on batteries with
secondary cells
Note 1 to entry: The battery energy storage system includes a flow battery energy system (IEC 62932-1:2020,
3.1.15).
Note 2 to entry: Batteries are defined in IEC 60050-482:2004, 482-01-04, and secondary cells are defined in
IEC 60050-482:2004, 482-01-03.
3.2
occupied site
location that is within or adjacent to a building or structure with an overhead cover, where
people live or work
Note 1 to entry: A location that is not an occupied site is called “unoccupied site”.
3.3
type test
conformity test made on one or more items representative of the production
[SOURCE: IEC 60050-151:2001, 151-16-16]
3.4
routine test
conformity test made on each individual item during or after manufacture
[SOURCE: IEC 60050-151:2001, 151-16-17]
3.5
factory acceptance test
FAT
factory activity to demonstrate that the EES system, subsystems, components and additionally
supplied systems/devices are in accordance with the specifications
[SOURCE: IEC 62381:2012, 3.1.3, modified – Original definition has been particularized for the
ESS system.]
3.6
site acceptance test
SAT
on site activity to demonstrate that the EES system can operate in accordance with the
applicable system specifications and installation instructions
[SOURCE: IEC 62381:2012, 3.1.4, modified – Original definition has been particularized for the
ESS system .]
4 Basic guidelines for safety of BESS
4.1 General
An assessment and reduction of the risk associated with the BESS as manufactured and as
intended to be installed shall be conducted according to the sequence shown in Figure 1.

Figure 1 – General description for risk assessment and reduction of BESS

– 12 – IEC 62933-5-2:2020 © IEC 2020
Risks can depend on many factors including location, chemistry and the size/scale (e.g. power)
of the BESS and will need to be assessed accordingly. The location of BESS can range from
single domestic situations, commercial and industrial applications, to utility scale systems; risks
need to be assessed accordingly. Selection of chemistry for the electrochemical accumulation
subsystem of the BESS can depend on their environment, performance characteristics and any
associated costs and benefits.
As described in ISO/IEC Guide 51, risk reduction measures taken during design are "inherently
safe design", "guards and protective devices", and "information for end users". Additional
measures at the use phase (life cycle safety management) are also described in ISO/IEC Guide
51.
4.2 Approach to BESS safety
The design of the BESS and its intended installation and integration with the built environment
shall accommodate the specific risks that arise during each phase of the BESS life cycle. These
life cycle phases typically include, but are not limited to:
• manufacturing/final assembly and factory acceptance testing (see 7.10, 7.11, and 8.2);
• transport (see 7.10, 7.11, and 8.2);
• installation, commissioning and site acceptance testing (see 7.10, 7.11, 7.12 and 8.2);
• operation (see 7.13);
• maintenance and repair (see 7.13);
• repurposing or decommissioning (see 7.13).
During the installation process, soundness of communication among subsystems which are
critical to minimizing risk and facilitating incident response shall be ensured to avoid any
malfunctions of the protection subsystems. After the installation of the BESS, these subsystems
shall be verified by inspection or other suitable means so that their proper functions are assured
before the BESS is placed into service.
All health, safety and environment (HSE) requirements applicable to the BESS as installed shall
be satisfied during system maintenance and repair.
The safety design considerations and risk analyses for each identified life cycle phase shall be
documented and supplied in accordance with Clause 6 and 7.13.
A BESS that is designed and constructed to provide a specified level of reliability and durability
shall include not only the levels of safety as a design feature of the overall system but also the
subsystem safety level which is necessary to achieve the specified level. At the subsystem level,
all integrated electrochemical energy storage subsystems shall comply with appropriate safety
standards (e.g. IEC 62477-1, IEC 62619).
Safety measures for interactions between subsystems shall be consistent with the result of the
system level safety risk assessment.
Commonly used electrochemical-based BESS POC (point of connection) voltages, energy
capacity, site occupancy and chemistry of electrochemical accumulation subsystems are
distinguished as listed in Table 1.
Detailed implementation of safety measures required in Clauses 7 and 8 can be optimized in
accordance with the result of the system risk assessment of BESS (see Clause 6) using the
basic conditions in Table 1.
NOTE 1 Chemistries that are not in common widespread use for stationary applications are not considered in this
document but can be considered in future editions

NOTE 2 "Energy capacity" of BESS" means the total energy capacity of electrochemical accumulation subsystems
which are equipped behind one POC.
Table 1 – BESS categories
Features for Category
Explanation
categorization denominations
“POC voltage” V-L Low: V ≤ 1 kV AC or 1,5 kV DC
where BESS is
V-H High: V > 1 kV AC or 1,5 kV DC
connected
“Energy capacity” E-S Small: E ≤ 20kWh
of BESS
E-L Not small: E > 20kWh
“Site occupancy” S-O Occupied site (see 3.2)
in relation to
S-U Unoccupied site (see 3.2)
electrochemical
accumulation
subsystem
“Chemistry” of C-A BESS using non-aqueous electrolyte battery (e.g. Li-based)
electrochemical
C-B BESS using aqueous electrolyte battery (e.g. Lead acid, Ni-based)
accumulation
subsystem
C-C BESS using high temperature battery (e.g. NaS, NaNiCl)
C-D BESS using flow battery
C-Z Others
NOTE 1 Denominations of BESS categorization are described as "V-X / E-X / S-X / C-X" in any requirements of
this document (e.g. V-H / /E-L / S-U / C-C). Some characteristics can be omitted if any limitation of category does
not apply.
NOTE 2 To apply this document to both BESS and other electrochemical-based EESS including chemical based
supercapacitors, the latter EESS are included in category "C-Z".
NOTE 3 Combinations of two or more electrochemical accumulation chemistries are included in category "C-Z".

Examples of BESS use can be described as shown in Table 2.

– 14 – IEC 62933-5-2:2020 © IEC 2020
Table 2 – Examples of BESS use
Use scene Site Access restrictions/conditions during operation and maintenance
Residential Installed in individual Can be placed in a location that is not accessible for regular
homes or shared by a maintenance without cooperation of the inhabitants of the home and is
small number of not part of a professional operating and maintenance regime.
homes and a large
number of apartments
buildings or villas.
An example of using Table 1 in this BESS use scene can be as follows: "V-L/E-S or L/S-O
or U/C-A or B".
Installed in small Placed in a location that is accessible for regular maintenance during
Commercial
businesses, shared by business hours and is usually part of a professional operating and
a large number of maintenance regime.
homes, or a mixture of
the above uses such
as a street or an
apartment building.
An example of using Table 1 in this BESS use scene can be as follows: "V-H or L/E-L/S-O
or U/C-A, B, C or D".
Industrial Installed in large Placed in a location that is accessible for regular maintenance during
businesses such as business hours and is part of a professional operating and maintenance
factories, data regime.
centers, warehouses
etc., or shared by a
large number of
homes, such as a city
quarter.
An example of using Table 1 in this BESS use scene can be as follows: "V-H/E-L/S-O or
U/C-A, B, C or D".
Utility Connected directly to Placed in a location that is continuously accessible for regular
the utility grid. maintenance and is part of a professional operating and maintenance
regime. The system is typically placed inside a restricted access area,
or access to the system itself is restricted to authorized people.
An example of using Table 1 in this BESS use scene can be as follows: "V-H/E-L/S-O or
U/C-A, B, C or D".
4.3 BESS changes in ownership, control or use
In all cases where a transfer of ownership or operational responsibility occurs, the monitoring
log information should be transferred to the new owner as part of the system documentation,
including measures for complying with the requirements in 7.13.2 and 7.13.3. When it is
necessary to control identified BESS risks, there should be clarification on the roles and
responsibilities for managing and controlling any existing or new safety risks arising out of the
changes that are planned or have taken place.
Annex A provides further information regarding ownership of BESS.
5 Hazard considerations
The general hazard considerations for EESS in IEC TS 62933-5-1:2017, Clause 5, are
applicable.
6 BESS system risk assessment
6.1 BESS structure
6.1.1 General characteristics
A storage model of the BESS shall be created for appropriate safety risk assessment with
clarifying features as shown below.
An example of a BESS including a primary POC, auxiliary POC and control subsystem is shown
in Figure 2 and Table 2. In some cases, it is possible that one or more subsystems or
components are not present. The communication arrangements between management,
communication, protection and the other subsystems are shown as dotted arrow lines.

Figure 2 – An example of BESS architecture
NOTE Figure 2 is an example and shows a typical BESS architecture. There can be cases which do not fit
in Figure 2.
– 16 – IEC 62933-5-2:2020 © IEC 2020
Table 3 – Examples of components within subsystems of a BESS
"Subsystems" "Components"
Management subsystem System controller and/or energy management system
Operation panel (human interface), system communication and/or monitoring,
Communication subsystem
meter communication
Protection subsystem Relays (earth, overcurrent, over-voltage, under-voltage, over-frequency,
under-frequency, etc.)
Auxiliary subsystem Fire, heat, and/or smoke detection system(s), fire suppression system, fire
extinguisher, HVAC (heating, ventilation and air conditioning), system
anchors, auxiliary transformers, auxiliary power distribution switchgear,
auxiliary power uninterruptible power supp
...