IEC 61558-2-15:2011

IEC 61558-2-15 ®
Edition 2.0 2011-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ

Safety of transformers, reactors, power supply units and combinations thereof –
Part 2-15: Particular requirements and tests for isolating transformers for the
supply of medical locations
Sécurité des transformateurs, bobines d’inductance, blocs d'alimentation et des
combinaisons de ces éléments –
Partie 2-15: Règles particulières et essais pour les transformateurs de
séparation de circuits pour locaux à usages médicaux

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IEC 61558-2-15 ®
Edition 2.0 2011-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ

Safety of transformers, reactors, power supply units and combinations thereof –
Part 2-15: Particular requirements and tests for isolating transformers for the
supply of medical locations
Sécurité des transformateurs, bobines d’inductance, blocs d'alimentation et des
combinaisons de ces éléments –
Partie 2-15: Règles particulières et essais pour les transformateurs de
séparation de circuits pour locaux à usages médicaux

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX R
ICS 29.180 ISBN 978-2-88912-790-0

– 2 – 61558-2-15  IEC:2011
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references. 6
3 Terms and definitions . 6
4 General requirements . 6
5 General notes on tests . 7
6 Ratings . 7
7 Classification . 7
8 Marking and other information . 7
9 Protection against electric shock . 8
10 Change of input voltage setting . 8
11 Output voltage and output current under load . 8
12 No-load output voltage . 8
13 Short-circuit voltage and inrush currents . 9
14 Heating . 10
15 Short-circuit and overload protection . 10
16 Mechanical strength . 10
17 Protection against harmful ingress of dust, solid objects and moisture . 10
18 Insulation resistance, dielectric strength and leakage current . 10
19 Construction . 12
20 Components . 14
21 Internal wiring . 14
22 Supply connection and other external flexible cables or cords. 14
23 Terminals for external conductors . 14
24 Provisions for protective earthing . 15
25 Screws and connections . 15
26 Creepage distances, clearances and distances through insulation . 15
27 Resistance to heat, fire and tracking . 15
28 Resistance to rusting . 15
Annexes . 16
Annex H Electronic circuits . 16
Annex L Routine tests (production tests) . 16
Bibliography . 17
Index of defined terms . 18

Figure 101 – The required circuit for measuring the leakage current from the output
winding to earth. 11
Figure 102 – The required circuit for measuring the leakage current at the protective
earth conductor . 12

61558-2-15  IEC:2011 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
SAFETY OF TRANSFORMERS, REACTORS,
POWER SUPPLY UNITS AND COMBINATIONS THEREOF –

Part 2-15: Particular requirements and tests
for isolating transformers for the supply of medical locations

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
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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 61558-2-15 has been prepared by IEC technical committee 96:
Transformers, reactors, power supply units and combinations thereof.
This second edition cancels and replaces the first edition published in 1999. It constitutes a
technical revision. The main changes consist of updating this part in accordance with
IEC 61558-1:2005.
This part has the status of a group safety publication in accordance with IEC Guide 104:2010,
The preparation of safety publications and the use of basic safety publications and group
safety publications.
– 4 – 61558-2-15  IEC:2011
The text of this standard is based on the following documents:
FDIS Report on voting
96/384/FDIS 96/385/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.
This part is intended to be used in conjunction with the latest edition of IEC 61558-1 and its
amendments. It is based on the second edition (2005) of that standard.
This part supplements or modifies the corresponding clauses in IEC 61558-1, so as to convert
that publication into the IEC standard: Particular requirements and tests for isolating
transformers for the supply of medical locations.
A list of all parts of the IEC 61558 series, under the general title: Safety of transformers,
reactors, power supply units and combination thereof, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
Where a particular subclause of Part 1 is not mentioned in this part, that subclause applies as
far as is reasonable. Where this part states "addition", "modification" or "replacement", the
relevant text of Part 1 is to be adapted accordingly.
In this part, the following print types are used:
– requirements proper: in roman type;
– test specifications: in italic type;
– explanatory matter: in smaller roman type:
In the text of this part, the words in bold are defined in Clause 3.
Subclauses, notes, figures and tables additional to those in Part 1 are numbered starting from
101; supplementary annexes are entitled AA, BB, etc.
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.
NOTE The attention of National Committees is drawn to the fact that equipment manufacturers and testing
organizations may need a transitional period following publication of a new, amended or revised IEC publication in
which to make products in accordance with the new requirements and to equip themselves for conducting new or
revised tests.
It is the recommendation of the committee that the content of this publication be adopted for implementation
nationally not earlier than 12 months from the date of publication.

61558-2-15  IEC:2011 – 5 –
SAFETY OF TRANSFORMERS, REACTORS,
POWER SUPPLY UNITS AND COMBINATIONS THEREOF –

Part 2-15: Particular requirements and tests
for isolating transformers for the supply of medical locations

1 Scope
Replacement:
This part of IEC 61558 deals with safety aspects of isolating transformers for the supply of
medical locations.
NOTE 1 Safety includes electrical, thermal and mechanical aspects.
Unless otherwise specified, from here onward, the term transformer covers isolating
transformers for the supply of medical locations.
This part is applicable to stationary, single-phase or three-phase, air-cooled (natural or forced)
independent dry-type isolating transformers for the supply of medical IT systems for group
2 medical locations, designed to be permanently connected to the fixed wiring and intended to
form the IT power system on the secondary side. The windings may be encapsulated or non-
encapsulated.
NOTE 2 IT power systems are defined in IEC 60364-1.
NOTE 3 The installation rules for medical IT systems for group 2 medical locations are covered by
IEC 60364-7-710.
NOTE 4 Transformers covered by this standard are intended for the supply of medical locations. All other
transformers or equipments connected downstream from the transformer are not covered by this Part 2.
The rated supply voltage does not exceed 1 000 V a.c. The rated supply frequency and
internal operational frequency do not exceed 500 Hz.
The rated output does not be less than 0,5 kVA and does not exceed 10 kVA for single-phase
and three-phase transformers.
This part is applicable to transformers without limitation of the rated output subject to an
agreement between the purchaser and the manufacturer.
NOTE 5 Transformers intended to supply power to distribution networks are not covered by this standard.
The no-load output voltage and the rated output voltage does not exceed 250 V a.c. for
single-phase or three-phase transformer (phase-to-phase voltage).
This standard do not cover power supply unit.
This part is not applicable to external circuits and their components intended to be connected
to the input terminals and output terminals of the transformers. Transformers covered by this
part are used in applications where double or reinforced insulation between circuits is
required by the installation rules or by the appliance specification.
NOTE 6 Attention is drawn to the following:

– 6 – 61558-2-15  IEC:2011
– for transformers intended to be used in vehicles, on board ships, and aircraft, additional requirements (from
other applicable standards, national rules, etc.) may be necessary;
– measures to protect the enclosure and the components inside the enclosure against external influences such
as fungus, vermin, termites, solar-radiation, and icing should also be considered;
– the different conditions for transportation, storage, and operation of the transformers should also be
considered;
– additional requirements in accordance with other appropriate standards and national rules may be applicable to
transformers intended for use in special environments.
2 Normative references
This clause of Part 1 is applicable, except as follows:
Addition:
IEC 61558-1:2005, Safety of power transformers, power supplies, reactors and similar products
– Part 1: General requirements and tests
3 Terms and definitions
This clause of Part 1 is applicable, except as follows:
Addition:
3.1.101
isolating transformer for the supply of medical locations
isolating transformer used for the supply of medical IT systems for group 2 medical locations,
designed to be permanently connected and with double or reinforced insulation between
each part of the transformer (body, screen, circuits, thermal sensitive device) except between
the core and the body
3.4.101
functional screening
separation between two windings or between a winding and the core or shielding of a part or of
the whole transformer, by means of a conductive material for functional reasons
3.5.101
rated input current
unput current, when the transformer is loaded with rated output
3.6.101
no-load input current
input current when the transformer is connected to the rated supply voltage, at the rated
frequency, with no-load on the output
3.6.102
inrush current
the maximum instantaneous value of the no-load input current of the transformer (peak
value) when is switched on at rated supply voltage
4 General requirements
This clause of Part 1 is applicable.

61558-2-15  IEC:2011 – 7 –
5 General notes on tests
This clause of Part 1 is applicable.
6 Ratings
This clause of Part 1 is applicable, except as follows:
Replacement:
6.1 The rated output voltage (phase-to-phase voltage) shall not exceed 250 V a.c. for
single-phase or three-phase transformers.
6.2 The rated output shall not be less than 0,5 kVA and it shall not exceed 10 kVA.
Transformers without limitation of the rated output shall be subject to agreement between the
purchaser and the manufacturer.
6.3 The rated frequency shall not exceed 500 Hz.
6.4 The rated supply voltage shall not exceed 1 000 V a.c.
Compliance with the requirements of 6.1 to 6.4 shall be verified by inspection of the marking.
7 Classification
This clause of Part 1 is applicable, except as follows:
7.2 Replacement:
According to short-circuit protection or protection against abnormal conditions:
– non-short-circuit proof transformer.
8 Marking and other information
This clause of Part 1 is applicable, except as follows:
8.1 h) Replacement:
Replace the first sentence by the following: Relevant graphical symbols shown in 8.11
indicating the type of transformer;
t) Addition:
Transformers shall be marked with the measured short-circuit voltage expressed as a
percentage of the rated supply voltage.
8.1.101 When the inrush current exceeds 8 times the peak value of the rated input current,
the resulting value shall be marked on the transformer.

– 8 – 61558-2-15  IEC:2011
8.11 Addition:
Symbol or graphical symbol Explanation or title Identification
non-short-circuit proof isolating transformer for IEC 60417-5972
the supply of medical locations (DB 2010-08)

8.14 Addition:
The instruction sheet shall state: “Screens whose connection to earth is necessary for
compliance with the leakage current requirements of Clause 18 shall be connected to earth.”
The instruction sheet shall qualify the type of temperature sensor built in the transformer, if
any. The instruction sheet shall give the required value of the circuit of the transformer, when it
is allowed by national installation rules.
9 Protection against electric shock
This clause of Part 1 is applicable.
10 Change of input voltage setting
This clause of Part 1 is applicable.
11 Output voltage and output current under load
This clause of Part 1 is applicable.
12 No-load output voltage
This clause of Part 1 is applicable, except as follows:
Addition:
The no-load output voltage shall be measured when the transformer is connected to the
rated supply voltage at the rated supply frequency and at the rated ambient temperature.
12.101 The no-load output voltage (phase-to-phase voltage) shall not exceed 250 V a.c.
single-phase or three-phase transformers.
12.102 The difference between the no-load output voltage, and the output voltage under
load shall not be excessive.
The difference is expressed as a percentage of the latter voltage calculated according to the
following formula:
61558-2-15  IEC:2011 – 9 –
V −V
no-load load
× 100 (%)
V
load
where V is the no-load output voltage and V is the output voltage under load.
no-load load
Compliance with the requirements of 12.101 and 12.102 shall be verified by measuring the no-
load output voltage and output voltage under load, at the rated ambient temperature when
the transformer is connected to the rated supply voltage at the rated supply frequency.
The difference between the no-load output voltage and the output voltage under load shall
not exceed 5 %.
13 Short-circuit voltage
This clause of Part 1 is not applicable.
Replacement:
13 Short-circuit voltage and inrush currents
13.1 The short-circuit voltage shall be measured and marked on the transformer.
Compliance shall be verified by measurements
13.2 The no-load input current shall not exceed 3 % of the rated input current at the rated
supply voltage.
This requirement shall be fulfilled by construction of the transformer without the use of any
capacitors in the transformer circuits (input/output) or in the installation.
Compliance shall be verified by measurements.
13.3 The inrush current shall not exceed 8 times the peak value of the rated input current.
However, it is allowed to increase this value to 12 times the rated input current; provided the
latter value shall be reflected on the transformer marking.
This requirement shall be fulfilled by construction of the transformer without the use of any
electronic devices and additional measures in the transformer or in the installation.
Compliance shall be verified by the following test:
The transformer with no load is connected to the rated supply voltage. The test supply
voltage is then switched on and off 20 times at random intervals of approximately 20 s.
NOTE The switching-on and -off may be carried out only twice if a device is used to switch on at the most
unfavourable electrical angle of the supply voltage.
The supply source shall be such that the voltage drop does not exceed 2 % as a result of the
inrush current.
The inrush current shall not exceed 8 times or 12 times the peak value of the rated input
current, respectively, during any of the switching events.

– 10 – 61558-2-15  IEC:2011
14 Heating
This clause of Part 1 is applicable, except as follows.
Addition:
14.101 Immediately after the test of 14.1 an additional heating test is required with 150 % of
the load for 30 min. After the test the temperature shall not exceed the values of Table 1
increased by 25 %.
15 Short-circuit and overload protection
This clause of Part 1 is applicable, except as follows:
Addition:
Isolating transformers for the supply of medical locations are non-short-circuit proof
transformers. The overload must be monitored by a temperature monitoring system. The test
of 15.3 of Part 1 will be carried out. When the circuit breaker is allowed by national installation
rules the value for a circuit-breaker shall be mentioned in the instruction sheet.
16 Mechanical strength
This clause of Part 1 is applicable.
17 Protection against harmful ingress of dust, solid objects and moisture
This clause of Part 1 is applicable.
18 Insulation resistance, dielectric strength and leakage current
This clause of Part 1 is applicable, except as follows:
18.2 Insulation resistance
th th
Table 7: Replacement of the 6 and 7 lines by the following:
Insulation to be tested Insulation resistance
MΩ
Between each input circuit and all other input circuits connected together 7
Between each output circuit and all other output circuits connected together 7
Between input and output circuits (double reinforced insulation)
NOTE In Australia, higher insulation resistance values are required.

61558-2-15  IEC:2011 – 11 –
18.3 Dielectric strength test
Table 8a: Addition:
Application of dielectric strength test voltage Working voltage
V
< 50 150 300 600 1 000
500 2 800 4 200 5 000 5 500
5) Between live parts of adjacent input circuits not
intended to be connected together
6) Between live parts of adjacent output circuits not 500 2 800 4 200 5 000 5 500
intended to be connected together

Addition:
18.101 The leakage current of the output winding to earth shall not exceed 0,5 mA, when
measured under the no-load condition, and at the room temperature with the transformer
supplied at the rated voltage and the rated frequency, as shown in Figure 101.
For this test the core and the functional screen, if any, shall be connected to earth.

Transformer
under test
Variable isolating
transformer
L
S1
T1
Mains S2
PRI SEC
V
N
Core
Screen
Enclosure
PE mA
IEC  2554/11
a) The test shall be carried out with all combinations of S1 and S2.
b) For three-phase transformers the switch S1 is used only in closed position. The measurements with switch S2
are repeated connecting it, in turn, to all phases.
c) The current is measured with an ammeter of negligible impedance.
NOTE In Japan, the leakage current of the output winding is limited to 0,1 mA maximum.
In Australia, additional leakage current limits apply.
Figure 101 – The required circuit for measuring the leakage current
from the output winding to earth

– 12 – 61558-2-15  IEC:2011
Compliance shall be verified by measurements.
18.102 The leakage current through the protective earth conductor from the enclosure to
earth, shall not exceed 0,5 mA when measured at room temperature under no-load condition
with the transformer supplied at the rated voltage and the rated frequency as shown in Figure
102.
Transformer
under test
Variable isolating
transformer
L
S1
T1
Mains
PRI SEC
V
N
Core
Screen
Enclosure
PE mA
IEC  2555/11
a) The test shall be carried out with all combinations of S1.
b) For three-phase transformers the switch S1 is used only in closed position.
c) The current is measured with an ammeter of negligible impedance.
d) The core, if not connected to the enclosure, and the functional screen, if any, shall be connected to earth.
Figure 102 – The required circuit for measuring the leakage current
at the protective earth conductor
Compliance shall be verified by measurements.
19 Construction
This clause of Part 1 is applicable, except as follows:
Replacement of 19.1 by the following:
19.1 The input and output circuits shall be electrically separated from each other, and the
construction shall be such that there is no possibility of any connection between these circuits,
either directly or indirectly, via other conductive parts, except by deliberate action.
Compliance is checked by inspection and measurements, taking Clauses 18 and 26 into
consideration.
61558-2-15  IEC:2011 – 13 –
19.1.101 The insulation between the input and output winding(s) shall consist of double or
reinforced insulation (rated for the working voltage). The insulation between the input
winding(s) and the body, and between the output winding(s) and the body, shall consist of
double or reinforced insulation (rated for the working voltage).
19.1.101.1 When the input winding(s) are not intended to be connected in series or parallel,
they shall be separated from one another and from other circuits by double or reinforced
insulation (rated for the working voltage).
The input winding(s), intended to be connected in series or parallel, may be separated from
each other by basic insulation (rated for the working voltage).
19.1.101.2 The output winding(s) shall be separated from each other and from other circuits
by double or reinforced insulation (rated for the working voltage).
19.1.101.3 The functional screening, if any, shall be separated from the core, the windings
and from the body by double or reinforced insulation (rated for the working voltage).
19.1.101.4 If the transformers are provided with a functional screening placed between the
input and the output windings, the functional screening shall be constructed of a metal foil
so that the adjacent turns overlap without short-circuiting. The lead out of the functional
screening shall be provided with separate terminals. For concentric windings, the width of the
functional screening shall be approximately equal to the axial winding length of the input
winding. For non concentric windings, the width of the functional screening shall be
approximately equal to the radial winding length of the input winding. If the functional
screening is constructed of only one turn it shall be provided with an insulated overlap of not
less than 3 mm.
19.1.102 For transformers with intermediate conductive parts (e.g. the iron core) not
connected to the body and located between the input and output windings, the insulation
between the intermediate conductive parts and the input windings, and between the
intermediate conductive parts and the output windings shall consist of at least basic
insulation (rated for the working voltage).
NOTE An intermediate conductive part not separated from the input or output windings or the body by at least
basic insulation is considered to be connected to the relevant part(s).
The insulation between the input and output windings via the intermediate conductive part
shall consist of double or reinforced insulation; the insulation between the input windings
and the body, and between the output windings and the body, via the intermediate
conductive part shall consist of double or reinforced insulation (rated for the working
voltage).
19.1.103 Transformers shall not be provided with capacitors electrically connecting the input
and the output circuits.
Compliance shall be verified by inspection.
19.1.104 The input and output terminals for the connection of external wiring shall be so
located that the distance measured between the points of introduction of the conductors into
these terminals is not less than 25 mm. If a barrier is used to obtain this distance, the
measurement shall be made over and around the barrier which shall be of insulating material
and permanently fixed to the transformer.
Compliance shall be verified by inspection and by measurement, disregarding the intermediate
conductive parts.
– 14 – 61558-2-15  IEC:2011
19.1.105 If the monitoring of the temperature is required, the thermal sensitive device
(bimetal, PTC or similar) shall be built-in and shall be connected to separate terminals for
external connections.
NOTE The terminals are intended to connect the temperature sensitive device to an acoustical and optical
temperature monitoring device located in the medical location and intended to warn the medical staff.
The temperature sensitive device shall be rated to the class of the insulation system minus
10 °C.
19.1.106 If a single-phase transformer is provided with a midpoint in the output winding, it
shall be connected to a separate terminal.
19.1.107 Three-phase transformers shall be provided with the vector group star-star or star-
delta design.
19.1.108 The star point of the output winding in three-phase transformers with vector group
star-star design shall be connected to a separate terminal.
NOTE The terminal is intended for connection to an external insulation monitoring device (IMD), if applicable.
19.1.109 The star point of the input winding in three-phase transformers with vector group
star-star or star-delta design shall be connected to a separate terminal.
NOTE The terminal is intended for connection to the neutral point of the supply in order to allow asymmetrical
loading.
19.1.110 Isolating transformers for the supply of medical locations shall be stationary
transformers.
20 Components
This clause of Part 1 is applicable, except as follows:
20.3 Replacement:
Socket-outlets are not allowed to connect the output circuit of the transformer to the
electrical installation of the medical room.
21 Internal wiring
This clause of Part 1 is applicable.
22 Supply connection and other external flexible cables or cords
This clause of Part 1 is applicable, except as follows:
22.7 This subclause of Part 1 is not applicable.
Isolating transformers for the supply of medical locations shall be designed for permanent
connection.
23 Terminals for external conductors
This clause of Part 1 is applicable.

61558-2-15  IEC:2011 – 15 –
24 Provisions for protective earthing
This clause of Part 1 is applicable.
25 Screws and connections
This clause of Part 1 is applicable.
26 Creepage distances, clearances and distances through insulation
This clause of Part 1 is applicable.
27 Resistance to heat, fire and tracking
This clause of Part 1 is applicable.
28 Resistance to rusting
This clause of Part 1 is applicable.

– 16 – 61558-2-15  IEC:2011
Annexes
The annexes of Part 1 are applicable, except as follows:
Annex H
Electronic circuits
This annex of Part 1 is not applicable.
Annex L
Routine tests (production tests)

This annex of Part 1 is applicable, except as follows:
Addition:
L.101 Checking of the short-circuit voltage
The short-circuit voltage shall not exceed the marked value.
L.102 Checking of the no-load input current
The no-load input current shall not exceed 3 % of the rated input current.
L.103 Checking of the inrush current
The inrush current shall not exceed 8 times the peak value of the rated input current or the
marked value on the label, if any.
Compliance is checked by 13.3 of this standard.

61558-2-15  IEC:2011 – 17 –
Bibliography
The Bibliography of Part 1 is applicable, except as follows:
Addition:
IEC 60364-1:2005, Low-voltage electrical installation – Part 1: Fundamental principles,
assessment of general characteristics, definitions
IEC 60364-4-41:2005, Low-voltage electrical installation – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-5-53, Electrical installations of buildings – Part 5-53: Selection and erection of
electrical equipment) – Isolation, switching and control
IEC 60364-7-710:2002, Electrical installations of buildings – Part 7-710: Requirements for
special installations or locations – Medical locations
IEC 61557-8:2007, Electrical safety in low voltage distribution systems up to 1 000 V a.c. and
1 500 V d.c. – Equipment for testing, measuring or monitoring of protective measures – Part 8:
Insulation monitoring devices for IT systems

– 18 – 61558-2-15  IEC:2011
Index of defined terms
The index of Part 1 is applicable, except as follows:
Addition:
functional screening 3.4.101
inrush current 3.6.102
isolating transformer for the supply of medical locations 3.1.101
no-load input current 3.6.101
rated input current 3.5.101
_____________
– 20 – 61558-2-15  CEI:2011
SOMMAIRE
AVANT-PROPOS . 21
1 Domaine d’application . 23
2 Références normatives . 24
3 Termes et définitions . 24
4 Exigences générales . 25
5 Généralités sur les essais . 25
6 Caractéristiques assignées . 25
7 Classification . 25
8 Marquage et indications . 25
9 Protection contre les chocs électriques . 26
10 Changement de la tension primaire d’alimentation . 26
11 Tension secondaire et courant secondaire en charge . 26
12 Tension secondaire à vide . 26
13 Tension de court-circuit et courants d'appel . 27
14 Échauffements. 28
15 Protection contre les courts-circuits et les surcharges . 28
16 Résistance mécanique . 28
17 Protection contre les effets nuisibles dus à la pénétration de poussière, d’objets
solides et de l’humidité . 28
18 Résistance d'isolement, rigidité diélectrique et courant de fuite . 28
19 Construction . 31
20 Composants . 33
21 Conducteurs internes . 33
22 Raccordement à l’alimentation et câbles souples externes . 33
23 Bornes pour conducteurs externes . 34
24 Dispositions en vue de la mise à la terre . 34
25 Vis et connexions . 34
26 Lignes de fuite, distances d’isolement et distances à travers l’isolation . 34
27 Résistance à la chaleur, au feu et aux courants de cheminement . 34
28 Protection contre la rouille . 34
Annexes . 35
Annexe H Circuits électroniques . 35
Annexe L Essais individuels en cours de fabrication (essais de routine) .
...