IEC 62485-2:2010

IEC 62485-2 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Safety requirements for secondary batteries and battery installations –
Part 2: Stationary batteries
Exigences de sécurité pour les batteries d’accumulateurs et les installations
de batteries –
Partie 2: Batteries stationnaires

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IEC 62485-2 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Safety requirements for secondary batteries and battery installations –
Part 2: Stationary batteries
Exigences de sécurité pour les batteries d’accumulateurs et les installations
de batteries –
Partie 2: Batteries stationnaires

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
W
CODE PRIX
ICS 29.220.20; 29.220.30 ISBN 978-2-88910-996-8
– 2 – 62485-2 © IEC:2010
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references.7
3 Terms and definitions .8
4 Protection against electric shock.10
4.1 General .10
4.2 Protection against direct contact .11
4.3 Protection against indirect contact .11
4.3.1 Protection by automatic disconnection of supply.12
4.3.2 Protection by use of class II equipment or by equivalent insulation .16
4.3.3 Protection by electrical separation.16
4.4 Protection against both direct and indirect contact.16
4.4.1 General .16
4.4.2 Protection by Safety Extra Low Voltage (SELV) or by Protective Extra
Low Voltage (PELV).16
4.4.3 Protection by Functional Extra Low Voltage (FELV) without protective
separation .17
5 Disconnection and separation .17
6 Prevention of short circuits and protection from other effects of electric current .17
6.1 General .17
6.2 Short-circuits .18
6.3 Protective measures during maintenance.18
6.4 Leakage currents.19
7 Provisions against explosion hazards .19
7.1 Gas generation.19
7.2 Ventilation requirements .19
7.3 Natural ventilation.21
7.4 Forced ventilation .22
7.5 Charging modes .22
7.6 Overcharging under fault conditions .22
7.7 Close vicinity to the battery .22
7.8 Prevention of electrostatic discharges when working with batteries.23
8 Provision against electrolyte hazard .23
8.1 Electrolyte and water .23
8.2 Protective clothing .23
8.3 Accidental contact and "First Aid".23
8.3.1 General .23
8.3.2 Eye contact.24
8.3.3 Skin contact.24
8.4 Battery accessories and maintenance tools.24
9 Accommodation, housing .24
9.1 General .24
9.2 Specific requirements for separate battery rooms.24
9.3 Specific requirements for the specially separated areas in rooms
accommodating electrical equipment .25

62485-2 © IEC:2010 – 3 –
9.4 Battery enclosures .25
9.5 Working on or near batteries.26
9.5.1 Working distances within battery rooms .26
9.5.2 Remarks on special work in battery rooms .26
9.6 Accommodation of lead-acid and NiCd batteries in the same room .26
10 Charge current requirements .26
10.1 Superimposed ripple current .26
10.2 Maximum ripple current .27
11 Identification labels, warning notices and instructions for use, installation and
maintenance.27
11.1 Warning labels and notices in rooms.27
11.2 Identification labels or marking on cells and monobloc batteries .27
11.3 Instructions for use, installation and maintenance .28
12 Transportation, storage, disposal and environmental aspects .28
12.1 Packing and transport.28
12.2 Dismantling, disposal, and recycling of batteries .28
13 Inspection and monitoring .28
Annex A (informative) Charging methods and modes of operation.30
Annex B (informative) Calculation of safety distance d to protect against explosion
hazards.34
Bibliography .37

Figure 1 – TN system with separate protective conductor (PE) in the entire system (TN-
S network) .13
Figure 2 – TN system with functional earthing and protective (FPE, PEN) combined with
an external line conductor (TN-C system) .13
Figure 3 – TT system .14
Figure 4 – IT system .15
Figure 5 – Converters with intermediate DC circuit (IT-system) (Example) .15
Figure A.1 – Parallel operation mode circuit.30
Figure A.2 – Battery charge current interlaced with frequent temporary discharge events
due to a load current exceeding the current supply capability.31
Figure A.3 – Response mode operation circuit.32
Figure A.4 – IU-or CC-CV charge profile.32
Figure A.5 – Time dependant profile of current I and voltage U .32
Figure B.1 – Safety distance d as a function of the rated capacity for various charge
currents I (mA/Ah).36

Table 1 – Values for current I when charging with IU- or U-charging profiles (see also
Annex A).21
Table 2 – Recommended upper limits of AC ripple current flowing through the battery
as I per 100 Ah rated battery capacity.27
eff
Table A.1 – Float charge voltages for lead-acid and NiCd batteries.30
Table A.2 – Typical charge voltage levels at 20 °C.33

– 4 – 62485-2 © IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY REQUIREMENTS FOR SECONDARY BATTERIES
AND BATTERY INSTALLATIONS –
Part 2: Stationary batteries
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62485-2 has been prepared by IEC technical committee 21:
Secondary cells and batteries.
The text of this standard is based on the following documents:
FDIS Report on voting
21/711/FDIS 21/718/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 62485 series can be found, under the general title Safety
requirements for secondary batteries and battery installations, on the IEC website.

62485-2 © IEC:2010 – 5 –
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 6 – 62485-2 © IEC:2010
INTRODUCTION
The described safety requirements comprise the protective measures to protect from hazards
generated by the electricity, the electrolyte, and the explosive gases when using secondary
batteries. In addition measures are described to maintain the functional safety of batteries and
battery installations.
For the electrical safety (protection against electric shock) under Clause 4, this standard refers
to IEC 60364-4-41. The pilot function of this standard is fully observed by indication of cross-
reference numbers of the relevant clauses, but interpretation is given where adoption to direct
current (DC) circuits is required.
This safety standard comes into force with the date of publication and applies to all new
batteries and battery installations. Previous installations are intended to conform to the existing
national standards at the time of installation. In case of redesign of old installations this
standard applies.
Valve-regulated lead-acid batteries used in stationary battery installations are intended to fulfil
safety requirements in accordance to IEC 60896-21 and IEC 60896-22.

62485-2 © IEC:2010 – 7 –
SAFETY REQUIREMENTS FOR SECONDARY BATTERIES
AND BATTERY INSTALLATIONS –
Part 2: Stationary batteries
1 Scope
This part of the IEC 62485 applies to stationary secondary batteries and battery installations
with a maximum voltage of DC 1 500 V (nominal) and describes the principal measures for
protections against hazards generated from:
– electricity,
– gas emission,
– electrolyte.
This International Standard provides requirements on safety aspects associated with the
erection, use, inspection, maintenance and disposal.
It covers lead-acid and NiCd / NiMH batteries.
Examples for the main applications are:
– telecommunications,
– power station operation,
– central emergency lighting and alarm systems,
– uninterruptible power supplies,
– stationary engine starting,
– photovoltaic systems.
2 Normative references
The following referenced documents are indispensable for the application 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 60364-4-41, Low-voltage electrical installations – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-4-43, Low-voltage electrical installations – Part 4-43: Protection for safety –
Protection against overcurrent
IEC 60364-5-53, Electrical installations of buildings – Part 5-53: Selection and erection of
electrical equipment – Isolation, switching and control
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60622:2002, Secondary cells and batteries containing alkaline or other non-acid
electrolytes –Sealed nickel cadmium prismatic rechargeable single cells
IEC 60623:2001, Secondary cells and batteries containing alkaline or other non-acid
electrolytes –Vented nickel-cadmium prismatic rechargeable single cells

– 8 – 62485-2 © IEC:2010
IEC 60664-1, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC/TR 60755, General requirements for residual current operated protective devices
IEC 60896-11:2002, Stationary lead-acid batteries – Part 11: Vented types – General
requirements and methods of tests
IEC 60896-21:2004, Stationary lead-acid batteries – Part 21: Valve regulated types – Methods
of test
IEC 60896-22:2004, Stationary lead-acid batteries – Part 22: Valve regulated types –
Requirements
IEC 60900, Live working – Hand tools for use up to 1 000 V a.c. and 1 500 V d.c.
IEC 61140, Protection against electric shock – Common aspects for installation and equipment
IEC 61340-4-1, Electrostatics – Part 4-1: Standard test methods for specific applications –
Electrical resistance of floor coverings and installed floors
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 62259:2003, Secondary cells and batteries containing alkaline and other non-acid
electrolytes – Nickel cadmium prismatic secondary single cells with partial gas recombination
ISO 3864 (all parts), Graphical symbols – Safety colours and safety signs
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
(secondary) cell
(rechargeable) cell
single cell
assembly of electrodes and electrolyte which constitutes the basic unit of a secondary battery
NOTE This assembly is contained in an individual case and closed by a cover.
3.2
vented (secondary) cell
secondary cell having a cover provided with an opening through which gaseous products may
escape
3.3
valve regulated (secondary) cell
secondary cell which is closed under normal conditions but has an arrangement which allows
the escape of gas if the internal pressure exceeds a predetermined value. The cell cannot
normally receive addition to the electrolyte

62485-2 © IEC:2010 – 9 –
3.4
gastight sealed (secondary) cell
secondary cell which remains closed and does not release either gas or liquid when operated
within the limits of charge and temperature specified by the manufacturer. The cell may be
equipped with a safety device to prevent dangerously high internal pressure. The cell does not
require addition to the electrolyte and is designed to operate during its life in its original sealed
state
3.5
secondary battery
two or more secondary cells connected together and used as a source of electrical energy
3.6
lead dioxide-lead (acid) battery
secondary battery with an aqueous electrolyte based on dilute sulphuric acid, a positive
electrode of lead dioxide and a negative electrode of lead
3.7
nickel oxide-cadmium battery
secondary battery with an alkaline electrolyte, a positive electrode containing nickel oxide and
a negative electrode of cadmium
3.8
stationary battery
secondary battery which is designed for service in a fixed location and is not habitually moved
from place to place during the operating life. It is permanently connected to the d.c power
supply (fixed installation)
3.9
monobloc battery
battery with multiple separate but electrically connected cell compartments each of which is
designed to house an assembly of electrodes, electrolyte, terminals and interconnections and
possible separator
NOTE The cells in a monobloc battery can be connected in series or parallel.
3.10
electrolyte
liquid or solid substance containing mobile ions which render it ionically conductive
NOTE The electrolyte may be liquid, solid or a gel.
3.11
gassing
gas emission
evolution of gas resulting from the electrolysis of water in the electrolyte of a cell
3.12
charge
charging (of a battery)
operation during which a secondary cell or battery is supplied with electrical energy from an
external circuit which results in chemical changes within a cell and thus storage of energy as
chemical energy occurs
3.13
battery on float charge
secondary battery whose terminals are permanently connected to a source of constant voltage
sufficient to maintain the battery approximately fully charged, and which is intended to supply
power to an electrical circuit, if the normal supply is temporarily interrupted

– 10 – 62485-2 © IEC:2010
3.14
float (charge) voltage
constant voltage needed to keep the cell or battery fully charged
3.15
float charge current
current resulting from the float charge
3.16
boost charge
accelerated charge applied at greater than normal values of electrical current or of voltages
(for a particular design) during a short time interval
3.17
boost charge voltage
constant voltage -at higher voltage level- used in the boost charge
3.18
boost charge current
current arising from the boost charge voltage
3.19
discharge
discharging (of a battery)
operation during which a battery delivers, to an external circuit and under specified conditions,
electrical energy produced in the cells
3.20
overcharge
overcharging (of a cell or battery)
continued charging after the full charge of a secondary cell or battery
NOTE Overcharge is also the act of charging beyond a certain limit specified by the manufacturer.
3.21
nickel-metal hydride battery
a secondary battery with an electrolyte of aqueous potassium hydroxide, a positive electrode
containing nickels as nickel hydroxide and a negative electrode of hydrogen in the form of a
metal hydride
3.22
nominal voltage
suitable approximate value of the voltage used to designate or indentify a cell, a battery or an
electrochemical system
4 Protection against electric shock
4.1 General
Measures shall be taken in stationary battery installations for protection against either direct
contact or indirect contact or against both direct and indirect contact.
These measures are described in detail in IEC 60364-4-41 and IEC 61140. The following
subclauses describe the typical measures to be taken for battery installations and the resulting
amendments.
62485-2 © IEC:2010 – 11 –
The appropriate equipment standard IEC 61140 applies to batteries and direct current
distribution circuits located inside equipment.
4.2 Protection against direct contact
In battery installations, protection against direct contact with live parts shall be ensured in
accordance with IEC 60364-4-41.
The following protective measures apply:
– ”protection by insulation of live parts”;
– ”protection by barriers or enclosures”;
– ”protection by obstacles”;
– ”protection by placing out of reach”.
Protection by obstacles or by placing out of reach is expressly permitted in battery installations.
It requires however that batteries with nominal voltages from >DC 60 V to DC 120 V between
terminals and/or with nominal voltages from >DC 60 V to DC 120 V with respect to earth shall
be located in accommodation with restricted access, and batteries with a nominal voltage
above DC 120 V shall be located in accommodation with restricted access achieved by locks or
other equivalent means. Doors to battery rooms and cabinets are regarded as obstacles and
shall be marked with the warning labels according to 11.1.
Protection against direct contact is not required for batteries with nominal voltages up to or
equal DC 60 V as long the whole installation corresponds to the conditions for SELV (safety
extra low voltage) and PELV (protective extra low voltage) (see 4.4.2).
NOTE The nominal voltage of a lead dioxide - lead cell (lead acid) is 2,0 V, that of a nickel oxide – cadmium or
nickel oxide - metal hydride cell is 1,2 V. When these cells are boost charged, their voltage may reach 2,7 V in lead
acid or 1,6 V in nickel oxide based systems.
Short circuit protection may be required, see 6.2.
If protection by barriers or enclosures is applied, degrees of protection IEC 60529 IP 2X or
IPXXB shall at least be used.
4.3 Protection against indirect contact
In battery installations, protection against indirect contact shall be applied in accordance with
IEC 60364-4-41.
One or more of the following measures shall be selected:
– ”protection by automatic disconnection of supply”;
– ”protection by use of class II equipment or by equivalent insulation”;
– ”protection by non-conducting locations” (used in specific applications only);
– ”protection by earth-free local equipotential bonding” (used in specific applications only);
– ”protection by electrical separation”.
A nominal touch voltage of DC 120 V shall not be exceeded (see IEC 60449, IEC 60364-4-41
and IEC/TS 61201). Beyond this voltage other suitable protection schemas shall be
implemented.
Certain of these methods of protection require a protective conductor. Protective conductors or
conductors with a protective function shall not be disconnected by a switching device. No
switching device is permitted in a protective conductor. They shall not contain over-current
protection devices (see IEC 60364-4-41). For dimensioning the cross-sectional areas of
protective conductors, see IEC 60364-5-54.

– 12 – 62485-2 © IEC:2010
Battery stands or battery cabinets made from metal shall either be connected to the protective
conductor or insulated from the battery and the place of installation. This insulation shall
correspond to the conditions for protection by insulation according to IEC 60364-4-41. Other
simultaneously accessible conductive parts, i.e. metal ducts, shall be out of reach. For
requirements on creepage distances and clearances (see IEC 60664-1), using a value of
4 000 V for the high-voltage impulse test.
The following protective devices shall be used with direct current, as applicable to the type of
power system:
a) fuses;
b) over-current protective devices;
c) residual current or differential protective devices (RCD’s), suitable for DC current.
The residual current protective devices in accordance with IEC/TR 60755 shall be of type B
suitable for DC fault current.
e) insulation monitoring devices (e.g. in IT-systems);
f) fault-voltage operated protective devices (see IEC 60364-4-41).
4.3.1 Protection by automatic disconnection of supply
4.3.1.1 TN-system
In a TN-system (see IEC 60364-4-41) the positive or negative terminal (see Figure 1 and
Figure 2) or the central point (in special cases also a non-central point) of the battery
installation shall be connected to earth.
The exposed conductive parts of the equipment shall be connected to the protective conductor
1 2 3
(PE) , the PEN-conductor (PEN) , or the earthing functional and protective conductor (FPE) ,
which is connected to the point on the battery having earth potential. Additional earthing of the
protective conductor may be required in order to ensure that its potential deviates as little as
possible from earth potential.
For fixed mounted electrical equipment, the disconnecting time shall be within 5 s after a fault
occurs.
NOTE For portable equipment and socket-outlet circuits IEC 60364-4-41, applies.
PE conductor: conductor provided for purposes of safety, for examples protection against electrical
shock
PEN conductor conductor combining the functions of both protective earthing conductor and neutral
conductor
___________
For definitions see IEC 60364-5-54.
Introduced with reference to IEC 60364-5-54.
For definitions see IEC 60950-1.

62485-2 © IEC:2010 – 13 –
L+
L–
PE
DC power source
Battery
Load
IEC  1337/10
Figure 1 – TN system with separate protective conductor (PE)
in the entire system (TN-S network)
In the TN-S system, the protective conductor (PE) shall be free of load current.

L+
L–
DC power source
Battery
IEC  1338/10
Load
Figure 2 – TN system with functional earthing and protective (FPE, PEN)
combined with an external line conductor (TN-C system)
In the TN-C system for DC-installations, the protective conductor and the earthed line
conductor carrying the load current are combined. The cross-sectional area of the PEN or FPE
conductor shall be at least 10 mm Cu.
4.3.1.2 TT-System
In a TT-System (see Figure 3) the positive or negative terminal or another point on the battery
installation shall be connected to earth (system earth electrode).
The exposed conductive parts of the electrical installation shall be earthed individually, in
groups or collectively to a common earth electrode which is separate from the system earth
electrode.
All exposed conductive parts collectively protected by the same protective device, shall be
connected together with protective conductors to an earth electrode common to all those parts.
Simultaneously accessible conductive parts shall be connected to the same earth electrode
(IEC 60364-4-41).
– 14 – 62485-2 © IEC:2010
Apart from the protective devices mentioned in 4.3, fault-voltage operated protective devices
are also applicable (IEC 60364-4-41)
In TT-system circuits, when the protective device is an over-current protective device, the
disconnecting time for all equipment shall be within 5 s, after a fault occurs. According to
IEC 60364-4-41 over-current protective devices shall be only applicable for protection against
indirect contact when a very low value earth resistance R exists.
a
NOTE R is the sum of the resistance of the earth electrode and the protective conductors for the exposed
a
conductive parts.
For discrimination purpose, disconnecting times of up to 1 s are admitted, when using residual
current devices.
L+
L–
DC power source
PE
PE
Battery
Load
IEC  1339/10
Figure 3 – TT system
4.3.1.3 IT-system
In an IT system (see Figure 4) no point of the battery installation is directly connected to earth.
It shall be insulated from earth or connected to earth through a sufficiently high impedance (e.g.
through an insulation monitoring device).
All exposed conductive parts of equipment shall be earthed individually, in groups or
collectively to a common earth electrode via a protective conductor.
Exposed conductive parts which are protected by a common protective device shall be
connected by protective conductors to a common earth electrode. Exposed conductive parts
which are simultaneously accessible shall be connected to the same earth electrode
(IEC 60364-4-41).
Apart from the safety devices mentioned in 4.3, insulation monitoring devices suitable for DC
voltages are also applicable.
In an IT-system, disconnection is not required at the occurrence of the first fault from a live
part to the exposed conductive parts or to earth. If an insulation monitoring device is provided,
this device shall initiate an audible and/or visual signal (IEC 60364-4-41).
Precautions shall be taken to prevent hazardous touch voltage levels in the event of a second
fault (e.g. disconnection by an over-current protective device, a residual current or fault voltage
protective device) (see IEC 60364-4-41).

62485-2 © IEC:2010 – 15 –
L+
L–
PE
DC power source
R <
Battery
Insulation
monitoring
device
Load
IEC  1340/10
Figure 4 – IT system
4.3.1.4 Intermediate DC current circuits with electrical connection to the AC supply
Systems of this type (see Figure 5) are used, for example, in intermediate DC circuits of
converter devices, e.g. UPS systems. Over-current protective devices are necessary in all
conductors which lead to the battery.

L1
L2
Inverter
Rectifier
Battery
PE
IEC  1341/10
Figure 5 – Converters with intermediate DC circuit (IT-system) (Example)
It shall be ensured that no AC voltage appears at the battery terminals whose rms voltage
value with respect to earth is above the maximum battery charging voltage. To ensure this, the
DC system can be provided with an appropriate detection device, which either monitors the
fault or disconnects the rectifier circuit.
The protective provisions applied in the single/three-phase AC supply shall -where technically
possible- be retained for the DC circuit, and if necessary extended by suitable ancillary
components so that, in the event of a fault, no hazardous touch voltage (> AC 50 V or
> DC 120 V) remains at the exposed conductive parts of the equipment.

– 16 – 62485-2 © IEC:2010
Residual current protective devices (RCD’s) in accordance with IEC 60755 shall be of type B
suitable for DC fault current.
4.3.2 Protection by use of class II equipment or by equivalent insulation
Protection by double or reinforced insulation shall be employed for electrical equipment to
comply with protection class II according to IEC 61140 or equipment with equivalent insulation
(see IEC 60364-4-41).
4.3.3 Protection by electrical separation
For the application of protection by electrical separation, see IEC 60364-4-41.
A separation source shall be used as the source of supply (IEC 60364-4-41).
An ”equivalent current source” within the meaning of IEC 60364-4-41 is a battery in which the
entire battery is insulated. The separation shall comply with the test requirements for protective
insulation in accordance with IEC 60364-4-41.
4.4 Protection against both direct and indirect contact
4.4.1 General
The protective provisions described in IEC 60364-4-41, safety extra low voltage (SELV) and
protective extra low voltage (PELV), shall only be used for battery installations with nominal
voltages up to DC 120 V.
They shall meet simultaneously the requirements for protection against either direct or indirect
contact.
NOTE In these cases, the requirements for metal battery stands and cabinets specified in 4.3 do not apply.
4.4.2 Protection by Safety Extra Low Voltage (SELV) or by Protective Extra Low
Voltage (PELV)
Protection against electric shock is ensured when the following conditions are met
simultaneously:
– the power source complies with the safety requirements in accordance with
IEC 60364-4-41, which reliably prevents the mains AC voltage exceeding the values
specified in IEC 60364-4-41, on the DC side in the event of a fault;
– the arrangement of the circuits complies with IEC 60364-4-4.
It shall be ensured that live parts or exposed conductive parts of SELV circuits cannot be
connected to live parts or exposed conductive parts of circuits of an other circuit.
If the nominal DC voltage of the battery installation does not exceed DC 60 V and the above
conditions are met, then in general, protection against direct contact with live parts may be
omitted (exceptions see IEC 60364-7-706).
Where the nominal voltages exceeds DC 60 V then protection against direct contact with live
parts shall be provided by
– barriers or enclosures of minimum protection type IEC 60529 IP 2X or IP XXB,
or
– insulation which withstands a test voltage of AC 500 V for 1 min according to
IEC 60364-4-41,
or
– protection through obstacles or distance which is expressly permitted in accordance with
4.2 in battery installations and battery rooms according to IEC 60364-4-41.

62485-2 © IEC:2010 – 17 –
4.4.3 Protection by Functional Extra Low Voltage (FELV) without protective
separation
If the nominal voltage does not exceed DC 120 V, and the requirements of subclause 4.4.2
– relevant to an electrochemical power source, which is independent or separated by
protection separation
and/or
– relevant to the arrangement of the circuits (e.g. connection of a conductor to the protective
conductor of the primary circuit)
cannot be met, then provisions shall be taken to ensure safety against direct and indirect
contact.
Protection against direct contact shall be ensured by
– insulation correlating at least with the lowest test voltage prescribed for the primary circuit
or
– barriers or enclosures which ensure minimum protection IP2x or IPXXB to IEC 60529.
Safety against indirect contact shall be ensured by
– connection of the exposed conductive parts of the equipment to the protective conductor of
the primary circuit when one of the protective measures is used as described in
IEC 60364-4-41
or by
– connection of the exposed conductive parts of the equipment to the non-earthed
equipotential bonding of the primary circuit if protective electrical separation in accordance
with IEC 60364-4-41 is used.
5 Disconnection and separation
Devices shall be provided to disconnect the battery installation from all lines of incoming and
outgoing circuits and from earth potential. These device
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