IEC 61558-2-16:2009/AMD1:2013

Amendment 1 - Safety of transformers, reactors, power supply units and similar products for supply voltages up to 1 100 V - Part 2-16: Particular requirements and tests for switch mode power supply units and transformers for switch mode power supply units

Amendement 1 - Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et produits analogues pour des tensions d'alimentation jusqu'à 1 100 V - Partie 2-16: Règles particulières et essais pour les blocs d'alimentation à découpage et les transformateurs pour blocs d'alimentation à découpage

General Information

• Status: Published
• Publication Date: 11-Aug-2013
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: TC 96 - Transformers and reactors
• Current Stage: DELPUB - Deleted Publication
• Start Date: 08-Jun-2021
• Completion Date: 26-Oct-2025

Relations

• Amends: IEC 61558-2-16:2009 - Safety of transformers, reactors, power supply units and similar products for supply voltages up to 1 100 V - Part 2-16: Particular requirements and tests for switch mode power supply units and transformers for switch mode power supply units
• Effective Date: 05-Sep-2023
• Revised: IEC 61558-2-16:2021 - Safety of transformers, reactors, power supply units and combinations thereof - Part 2-16: Particular requirements and tests for switch mode power supply units and transformers for switch mode power supply units for general applications
• Effective Date: 05-Sep-2023

Overview

IEC 61558-2-16:2009/AMD1:2013 is an important amendment issued by the International Electrotechnical Commission (IEC) that updates the safety requirements for transformers, reactors, power supply units, and similar products designed for supply voltages up to 1,100 V. Specifically, this amendment addresses Part 2-16, which focuses on the particular requirements and tests for switch mode power supply units (SMPS) and transformers for SMPS.

The amendment primarily introduces provisions for the use of Fully Insulated Winding (FIW) wires in switch mode power supplies, enhancing safety protocols to prevent damage during production and transport, and ensuring robust electrical performance through rigorous testing.

Key Topics

• Scope and Safety Focus: Enhancing safety for transformers, reactors, and power supply units operating up to 1,100 V, particularly focusing on SMPS components.

• Introduction of Fully Insulated Winding (FIW) Wires: The amendment permits the use of FIW wires, which are zero-defect, fully insulated winding wires compliant with IEC 60317 series and IEC 60851-5 standards. These wires provide improved insulation properties essential in SMPS design.

• Testing Requirements: New and specific test methods have been incorporated:

  • Partial Discharge Tests for FIW wires when the recurring peak working voltage exceeds 750 V, ensuring the integrity of the insulation.
  • Thermal Cycling Tests involving repeated temperature cycles with voltage tests applied to FIW windings to guarantee reliability under operational stresses.
  • Dielectric Strength and Insulation Resistance Tests, modified to accommodate FIW wire characteristics and to verify robust insulation under real-life operating conditions.

• Construction and Insulation Criteria:

  • Defines layers of insulation needed for basic, supplementary, and reinforced insulation using FIW wires.
  • Specifies mechanical separation requirements between insulated FIW wires and enamelled wires or cores.
  • Details on creepage distances and clearance exceptions granted by FIW wire construction.
  • Limits usage of FIW wires to insulation classes up to class F for transformers.

• Normative References: Incorporates relevant IEC standards such as IEC 60317 (winding wires specifications) and IEC 60851 (test methods for winding wires), establishing a comprehensive framework for wire quality and testing.

Applications

IEC 61558-2-16:2009/AMD1:2013 applies widely across industries using switch mode power supply units, including but not limited to:

• Consumer Electronics: SMPS used in chargers, adapters, and other electronic devices benefit from improved wire insulation safety.
• Industrial Power Supplies: Ensures that industrial-grade transformers and power units meet enhanced insulation and reliability standards.
• Automotive Electronics: Safety-critical power supplies in electric vehicles and other transportation devices require compliance with these updated safety norms.
• Medical Equipment: Reliable transformer insulation is crucial in sensitive health devices where power supply failure or electrical hazards are unacceptable.
• Renewable Energy Systems: SMPS transformers within solar inverters or wind turbines benefit from improved durability and safety compliance.

By applying the amendment, manufacturers ensure safer, more reliable products that minimize electrical failure risk and conform to international safety regulations.

Related Standards

For comprehensive compliance and design integration, the following related IEC standards are essential references linked to IEC 61558-2-16 amendment:

• IEC 60317 Series: Specifications for particular types of winding wires, including fully insulated enamelled round copper wires used in FIW applications.
• IEC 60851 Series: Test methods for winding wires covering mechanical and electrical properties critical to insulation verification.
• IEC 60664-1: Insulation coordination for equipment within low-voltage systems, relevant for partial discharge testing guidelines.
• IEC 61800-5-1: Safety requirements for adjustable speed electrical power drive systems, referenced for more stringent insulation needs where applicable.

---

Keywords: IEC 61558-2-16 amendment, switch mode power supply safety, fully insulated winding wires, FIW wire standards, SMPS transformer insulation, partial discharge testing, dielectric strength tests, IEC winding wire standards, power supply unit safety, insulation requirements for transformers.

Standards Content (Sample)

IEC 61558-2-16 ®
Edition 1.0 2013-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ

AMENDMENT 1
AMENDEMENT 1
Safety of transformers, reactors, power supply units and similar products for
supply voltages up to 1 100 V –
Part 2-16: Particular requirements and tests for switch mode power supply units
and transformers for switch mode power supply units

Sécurité des transformateurs, bobines d’inductance, blocs d'alimentation et
produits analogues pour des tensions d’alimentation jusqu'à 1 100 V –
Partie 2-16: Règles particulières et essais pour les blocs d'alimentation à
découpage et les transformateurs pour blocs d'alimentation à découpage

IEC 61558-2-16:2009/A1:2013
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IEC 61558-2-16 ®
Edition 1.0 2013-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ

AMENDMENT 1
AMENDEMENT 1
Safety of transformers, reactors, power supply units and similar products for

supply voltages up to 1 100 V –

Part 2-16: Particular requirements and tests for switch mode power supply units

and transformers for switch mode power supply units

Sécurité des transformateurs, bobines d’inductance, blocs d'alimentation et

produits analogues pour des tensions d’alimentation jusqu'à 1 100 V –

Partie 2-16: Règles particulières et essais pour les blocs d'alimentation à

découpage et les transformateurs pour blocs d'alimentation à découpage

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX M
ICS 29.180 ISBN 978-2-8322-0996-7

– 2 – 61558-2-16 Amend. 1 © IEC:2013
FOREWORD
This amendment has been prepared by IEC technical committee 96: Transformers, reactors,
power supply units, and combinations thereof.
The text of this amendment is based on the following documents:
FDIS Report on voting
96/401/FDIS 96/405/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base 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.
_____________
INTRODUCTION to the Amendement
This amendment has been prepared to allow the use of FIW wires in SMPS.
The manufacturer should be careful, that during production and transport no damage of the
FIW wire will be possible.
_____________
2 Normative references
Add, to the existing list of references, the following new references:
IEC 60317-0-7:2012, Specifications for particular types of winding wires – Part 0-7: General
requirements – Fully insulated (FIW) zero-defect enamelled round copper wire with nominal
conductor diameter of 0,040 mm to 1,600 mm

61558-2-16 Amend. 1 © IEC:2013 – 3 –
IEC 60317-43, Specifications for particular types of winding wires – Part 43: Aromatic
polyimide tape wrapped round copper wire, class 240
IEC 60317-56, Specifications for particular types of winding wires – Part 56: Solderable fully
insulated (FIW) zero-defect polyurethane enamelled round copper wire with nominal
conductor diameter 0,040 mm to 1,600 mm, class 180
IEC 60851-3:2009, Winding wires – Test methods – Part 3: Mechanical properties
IEC 60851-5:2008, Winding wires – Test methods – Part 5: Electrical properties
3 Terms and definitions
Add, at the end of the existing text, the following new instruction and new terms and
definitions as follows:
Addition:
3.101
FIW
fully insulated winding wire
wire according to IEC 60317-0-7, IEC 60317-56 and IEC 60851-5:2008 which is a zero-defect
wire construction
3.102
zero-defect wire
winding wire that exhibits no electrical discontinuities when tested under specific conditions
3.103
grade of FIW
range of overall diameter of a wire (FIW3 – FIW9)
18 Insulation resistance, dielectric strength and leakage current
18.3
Add, after the existing Table 8a, the following new instruction:
Replacement of the text in footnote a of Table 8a:
a
For construction according to 26.2.4.1, test B the voltage is multiplied by the factor 1,25. For
the construction according to 26.2.4.2 the voltage is multiplied by the factor 1,35.
Add, after the existing subclause 18.101, the following new subclause and new figure:
18.102 A partial discharge test according to IEC 60664-1, (test description see below) shall
be performed, if FIW wires are used and if the recurring peak working voltage U across the
t
insulation is greater than 750 V. The relevant recurring peak voltage is the maximum
measured voltage between the input and the output circuit of the SMPS, if the secondary side
is earthed. The measuring shall be done at 1,0 of the maximum rated input voltage.
A partial discharge test shall be done at the transformer for the SMPS with the measured
recurring peak voltage U , greater than 750 V peak.
t
U is the maximum peak working voltage;
t
is 5 s;
t
– 4 – 61558-2-16 Amend. 1 © IEC:2013
t is 15 s.
Partial discharge shall be less than or equal to 10 pC at time t .
The test shall be done according to the following Figure 104.
For other applications higher values may be required (e.g. IEC 61800-5-1).
U
1,25 U
t
U
t
t
t t
1 1
IEC  1763/13
Figure 104 – Test voltages
19 Construction
Add, at the end of the existing text of this clause, the following new text:
19.12.3 Replacement:
Insulated winding wires, in an insulation system providing basic, supplementary or
reinforced insulation, shall meet the following requirements.
Wire that has multi-layer extruded or spirally wrapped insulation (where only the finished wire
can be tested) and passes the tests of Annex K.
The minimum number of constructional layers applied to the conductor shall be as follows:
– BASIC INSULATION: two wrapped layers or one extruded layer;
– SUPPLEMENTARY INSULATION: two layers, wrapped or extruded;
– REINFORCED INSULATION: three layers wrapped or extruded.
For spirally wrapped insulation where the CREEPAGE DISTANCES between layers, as wrapped,
are less than those given in Clause 26. for pollution degree 1, the path between layers shall
be sealed as for a cemented joint in 26.2.3, Test A and the test voltages of the TYPE TESTS in
Clause K.2 are increased to 1,35 times their normal values.
NOTE 1 One layer of material wound with more than 50 % overlap is considered to constitute two layers.

61558-2-16 Amend. 1 © IEC:2013 – 5 –
The finished component shall pass ROUTINE TEST for electric strength using the appropriate
value of test voltages in 18.3.
Compliance is checked by inspection and measurement and, if applicable, as specified in
Annex K.
a) Where the insulation on the winding wire is used to provide basic- or supplementary
insulation in a wound part:
– the insulated wire (for example polyimide or insulation of equivalent quality) shall
comply with Annex K;
– the insulation of one insulated winding wire shall consist of at least two layers for
supplementary insulation;
– the insulation of one insulated winding wire shall consist of at least one layer for
basic insulation;
– an insulation for mechanical separation which fulfil the electric strength test for basic
insulation shall be provided between the insulated wires and the enamelled wires.
NOTE 2 If for basic or supplementary insulation a triple insulated wire is used in combination with
enamelled wire, an additional interleaved insulation (mechanical separation) is not required.
b) Where the insulation on the winding wire is used to provide reinforced insulation in a
wound part:
– the insulated wire (for example polyimide or insulation of equivalent quality) shall
comply with Annex K;
– the insulation of one insulated winding wire shall consist of at least three layers;
– the insulation is subjected to the relevant dielectric strength test of 18.3.
Where the insulated winding wire is wound:
– upon metal or ferrite cores or
– upon enamelled wire or;
– under enamelled wire;
an insulation for mechanical separation which fulfil the electric strength test for basic
insulation shall be provided between the insulated wires and the core or between the
insulated wires and the enamelled wires. The both windings shall not touch each other and
both wires shall not touch the core.
NOTE 3 This requirement takes into consideration the mechanical production stress applied to the insulated
winding wires.
The manufacturer of the transformer shall demonstrate that the winding wire has been
subjected to 100 % routine dielectric strength test as in Clause K.3.
No requirements for creepage distances and clearances are applicable for the insulated
winding wires.
For windings providing reinforced insulation, no value is required in box 2) c) of Table 13,
Table C.1 and Table D.1 of Part 1 and no values are required of 26.106.
Compliance is checked by inspection of the part and the declaration of the wire manufacturer
19.12.101 The transformer which use fully insulated winding wires (FIW), shall only be used
up and including insulation class F.
19.12.102 Fully insulated winding wires (FIW) shall comply with IEC 60851-5:2008,
IEC 60317-0-7 and IEC 60317-56. If the wire has other nominal diameter than in Table 111
defined, so the minimum high voltage strength value can be calculated according to formula
below Table 111:
– 6 – 61558-2-16 Amend. 1 © IEC:2013
• FIW wires used for basic or supplementary isolation for transformers according to 19.1.2:
– the test voltage required in Table 8a for basic/supplementary insulation according to
the working voltage of the transformer, shall comply with the minimum voltage strength
of basic insulation for the FIW-wire according to Table 111;
– between an basic insulated FIW wire and an enamelled wire an insulation for
mechanical separation shall be used. The both windings shall not touch each other.
The insulation for mechanical separation shall fulfil the high voltage test of basic
insulation. Creepage distances and clearances to the FIW wire are not required.
• FIW wires used for double or reinforced insulation according to 19.1.3:
– the test voltage required in Table 8a for basic-/supplementary insulation according to
the working voltage of the transformer, shall comply with the minimum voltage strength
of basic insulation for the FIW-wires according to Table 111. For the primary and the
secondary winding a basic insulated FIW wire shall be used;
– between the two basic insulated FIW wires an insulation for mechanical separation
shall be used. The both windings shall not touch each other. The insulation for
mechanical separation shall fulfil the high voltage test of basic insulation. Creepage
distances and clearances between the FIW wires are not required.
• Alternative construction with FIW-wires reinforced insulated:
– the test voltage required in Table 8a for reinforced insulation according to the working
voltage of the transformer, shall comply with the minimum voltage strength for the FIW
wire according to Table 111;
– between a reinforced insulated FIW wire and an enamelled wire an insulation for
mechanical separation shall be used. The both windings shall not touch each other.
The insulation for mechanical separation shall fulfil the high voltage test of basic
insulation. Creepage distances and clearances to the FIW wire are not required.
• Alternative construction with FIW wires, basic or supplementary insulated for transformers
with double or reinforced insulation according to 19.1.3:
– the test voltage required in Table 8a for basic-/supplementary insulation according to
the working voltage of the transformer, shall comply with the minimum voltage strength
of basic insulation for the FIW-wire according to Table 111. For the primary or the
secondary winding a basic insulated FIW wire shall be used. For the other winding
enamelled wire can be used;
– between the basic insulated FIW wire and the enamelled wire an supplementary
insulation according to the working voltage is required. Creepage distances and
clearances between the FIW wire and the enamelled wire are required for
supplementary insulation.
• Where the FIW wire is wound:
– upon metal or ferrite cores, an insulation for mechanical separation which fulfil the
electric strength test for basic insulation shall be provided between the FIW wires and
the core.The FIW wire and enamelled wire (if used) shall not touch the metal or ferrite
core.
26 Creepage distances, clearances and distances through insulation
Add, at the end of the existing clause, the following new subclause:
26.107 For transformers with FIW wires the following test is required:
To test the FIW-winding at the final transformer, three specimens shall be used.
The specimens shall be subjected 10 times to the following sequence of temperature cycles:
68 h at
the highest winding temperature ± 2 °C measured in normal use plus 10 K with a
minimum of 85 °C;
61558-2-16 Amend. 1 © IEC:2013 – 7 –
1 h at
25 °C ± 2 °C;
2 h at
0 °C ± 2 °C;
1 h at
25 °C ± 2 °C.
During each thermal cycling test, a voltage of twice the value of the working voltage at 50 Hz
or 60 Hz shall be applied to the specimens between the windings where the reduced values
apply.
Two of the three specimens are then subjected to the humidity treatment of 17.2 (48 h
treatment) and the relevant dielectric strength test of 18.3.
One of the three specimens shall be subjected to the relevant dielectric strength test of 18.3
immediately at the end of the last period at highest temperature during the thermal cycling
test.
The partial discharge test shall be done at the end of the cycling test at normal room
temperature as performed in 18.101.

– 8 – 61558-2-16 Amend. 1 © IEC:2013

Table 111 – Values of FIW wires with maximum overall diameter
and minimum test voltages according to the enamel increase

61558-2-16 Amend. 1 © IEC:2013 – 9 –
The values of allowed voltage strength for other FIW dimensions than defined in Table 111
are calculated according following formula:
d − d
a cu 3
V= ×U×10
where
d is the maximum overall diameter in (mm);
a
d is the nominal copper diameter in (mm);
cu
U is the voltage value according to Table 7 of IEC 60317-0-7 (see column 2) in (V/µm);
V is the allowed voltage strength for FIW wire in (V).
Higher voltage values, based on the "enamel increase" of Table 7 of IEC 60317-0-7:2012, are
under consideration.
Annexes
Add, before the existing word "Addition", the following new text and new annex as follows:
Replacement of Annex K:
– 10 – 61558-2-16 Amend. 1 © IEC:2013
Annex K
(normative)
Insulated winding wires
K.1 General
This annex specifies the winding wires of the insulation that may be used to provide basic
insulation, supplementary insulation, double insulation or reinforced insulation in
wound components. For details of the construction, see 19.12.3.
This annex applies to solid circular winding wires and stranded winding wires having
diameters between 0,05 mm and 5,0 mm and solid square and solid rectangular (flatwise
bending) winding wires with equivalent cross-sectional areas (0,002 to 19,6 mm ).
If the wire is insulated with two or more spirally wrapped layers of tape, the overlap of layers
shall be adequate to ensure continued overlap during manufacture of the wound component.
The layers of spirally wrapped wire insulation shall be sufficiently secured to maintain the
amount of overlap.
K.2 Type tests
K.2.1 General
The winding wire shall pass the following type tests, carried out at a temperature between
15 °C and 35 °C and a relative humidity between 25 % and 75 %, unless otherwise specified.
K.2.2 Electric strength
K.2.2.1 Solid circular winding wires and stranded winding wires
The test sample is prepared according to 4.4.1 of IEC 60851-5:2008 (twisted pair). The
sample is then subjected to the electric strength test of 18.3 in this standard with a test
voltage standard, with a minimum of:
– 6 kV r.ms. for reinforced insulation, or
– 3 kV r.m.s. for basic insulation or supplementary insulation.
K.2.2.2 Square or rectangular wires
The test sample is prepared according to 4.7.1 of IEC 60851-5:2008 (single conductor
surrounded by metal shots). The sample is then subjected to the electric strength test of 18.3
of this standard, with a minimum test voltage of:
– 5,5 kV r.m.s. for reinforced insulation, or
– 2,75 kV r.m.s. for basic insulation or supplementary insulation.
K.2.3 Flexibility and adherence
5.1 (in Test 8) of IEC 60851-3:2009 shall be used, using the mandrel diameters of Table K.1.
The test voltage is applied between the wire and the mandrel.
The test sample is then examined in accordance with 5.1.1.4 of IEC 60851-3:2009, followed
by the electric strength test of 18.3 in this standard, with minimum test voltage of:
– 5,5 kV r.m.s. for reinforced insulation, or

61558-2-16 Amend. 1 © IEC:2013 – 11 –
– 2,75 kV r.m.s. for basic insulation or supplementary insulation.
The test voltage is applied between the wire and the mandrel.
Table K.1 – Mandrel diameter
Nominal conductor Mandrel diameter
diameter or thickness
mm mm
up to but excluding
0,35
4,0 ± 0,2
0,50 6,0 ± 0,2
0,75 8,0 ± 0,2
2,50
10,0 ± 0,2
a
5,00 Four times the conductor diameter or thickness
a
In accordance with IEC 60317-43.

The tension to be applied to the wire during winding on the mandrel is calculated from the
wire diameter to be equivalent to 118 MPa ± 10 % (118 N/mm ± 10 %).
Edgewise bending on the smaller dimension side (width) is not required for rectangular wire.
For mandrel winding test of the square and rectangular wire, two adjacent turns do not need
to contact each other.
K.2.4 Heat shock
The test sample shall prepared in accordance with 3.1.1 (in Test 9) of IEC 60851-6:1996,
followed by the electric strength test of 18.3 in this standard, with a minimum test voltage of:
– 5,5 kV r.m.s. or for reinforced insulation, or
– 2,75 kV r.m.s for basic insulation or supplementary insulation.
The test voltage is applied between the wire and the mandrel. The oven temperature is the
relevant temperature of the thermal class of insulation in Table K.2. The mandrel diameter
and tension applied to the wire during winding on the mandrel are as in Table K.1. The test
voltage is applied between the wire and the mandrel.
The electric strength test is conducted at room temperature after removal from the oven.
Table K.2 – Oven temperature
Class 105 Class 120 Class 130 Class 155 Class 180
Thermal class
(A) (E) (B) (F) (H)
Oven temperature °C 200 215 225 250 275

Edgewise bending on the smaller dimension side (width) is not required for rectangular wire.
NOTE 3.1.2 in Test 9 of IEC 60851-6:1996 is not used for solid square and solid rectangular winding wires.
K.2.5 Retention of electric strength after bending
Five samples are prepared as in K.2.3 and tested as follows. Each sample is removed from
the mandrel, placed in a container and positioned so that it can be surrounded by at least
5 mm of metal shot. The ends of the conductor in the sample shall be sufficiently long to avoid
flash over. The shot shall be not more than 2 mm in diameter and shall consist of balls of
stainless steel, nickel or nickel plated iron. The shot is gently poured into the container until

– 12 – 61558-2-16 Amend. 1 © IEC:2013
the sample under test is covered by at least 5 mm of shot. The shot shall be cleaned
periodically with a suitable solvent.
NOTE The above test procedure is reproduced from 4.6.1 c) of IEC 60851-5:1988 but is not included in the fourth
edition (2008) of that standard.
The samples shall be subjected to the electric strength test of 18.3 in this standard, with a
minimum test voltage of:
– 5,5 kV r.m.s. for reinforced insulation, or
– 2,75 kV r.m.s. for basic insulation or supplementary insulation.
The mandrel diameter and tension applied to the wire during winding on the mandrel are as in
K.2.
K.3 Testing during manufacturing
K.3.1 General
The wire shall be subjected by the wire manufacturer to electric strength tests during
manufacture as specified in K.3.2 and K.3.3.
K.3.2 Routine test
The test voltage for routine test shall be in accordance with the electric strength test of 18.3
in this standard, with a minimum of:
– 4,2 kV r.m.s. for reinforced insulation, or
– 2,1 kV r.m.s. for basic insulation or supplementary insulation.
K.3.3 Sampling test
K.3.3.1 Solid
...