EN 60127-6:1994

SLOVENSKI STANDARD
01-december-1995
Miniature fuses - Part 6: Fuse-holders for miniature cartidge fuse-links (IEC 127-
6:1994)
Miniature fuses -- Part 6: Fuse-holders for miniature fuse-links
Geräteschutzsicherungen -- Teil 6: G-Sicherungshalter für G-Sicherungseinsätze
Coupe-circuit miniatures -- Partie 6: Ensembles-porteurs pour éléments de
remplacement miniatures
Ta slovenski standard je istoveten z: EN 60127-6:1994
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
INTERNATIONALE IEC
127-6
INTERNATIONAL
Première édition
STANDARD
First edition
1994-04
Coupe-circuit miniatures –
Partie 6:
cartouches
Ensembles-porteurs pour
de coupe-circuit miniatures
Miniature fuses –
Part 6:
Fuse-holders for miniature
cartridge fuse-links
réservés — Copyright — all rights reserved
© CEI 1994 Droits de reproduction
of this publication may be reproduced or utilized in
Aucune partie de cette publication ne peut être reproduite ni No part
utilisée sous quelque forme que ce soit et par aucun pro- any form or by any means, electronic or mechanical,
including photocopying and microfilm, without permission
cédé, électronique ou mécanique, y compris la photocopie et
in writing from the publisher.
les microfilms, sans l'accord écrit de l'éditeur.
Suisse
reau Central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève,
Bu
Commission Electrotechnique Internationale CODE PRIX
International Electrotechnical Commission
PRICE CODEPRICE CODE
iyuapoman 3neltrpoTexHH4ecKaR HOMHCCHR
IEC Mes
vigueur
Pour prix, voir catalogue en
For price, see current catalogue

127-6 ©IEC:1994 – 3 –
CONTENTS
Page
FOREWORD 5
INTRODUCTION 7
Clause
1 Scope and object 9
2 Normative references
3 Definitions
4 General requirements
5 Preferred standard ratings and classifications for fuse-holders
6 Marking 21
7 Information for the user of fuse-holders
8 General notes on tests
9 Protection against electric shock 27
10 Clearances and creepage distances 27
11 Electrical requirements
12 Mechanical requirements
13 Thermal requirements
14 Endurance
15 Additional requirements 73
Annexes
A Test PC board for rated currents from 6,3 A to 10 A
B Type tests, test sequences and number of samples
C Insulation co-ordination
D Additional tests and requirements 85
Information for the correct application of the fuse-holder E

127-6
Oo IEC:1994 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
MINIATURE FUSES –
Part 6: Fuse-holders for miniature cartridge fuse-links
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
Their preparation is entrusted to technical committees; any IEC National Committee interested in
the subject dealt with may participate in this preparatory work. International, governmental and
non-governmental organizations liaising with the IEC also participate in this preparation. The IEC
collaborates closely with the International Organization for Standardization (ISO) in accordance with
conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of the IEC on technical matters, prepared by technical committees on
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
3) They have the form of recommendations for international use published in the form of standards, technical
reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
International Standard IEC 127-6 has been prepared by sub-committee 32C: Miniature
fuses, of IEC technical committee 32: Fuses.
This first edition of IEC 127-6 cancels and replaces the first edition of IEC 257 published
in 1968 and amendment 2 to IEC 257 published in 1989.
The text of this standard is based on the following documents:
DIS Report on voting
32C(CO)71
32C(CO)72
32C(CO)71 A
Full information on the voting for the approval of this standard can be found in the repo rt
on voting indicated in the above table.
Annexes A and B form an integral part of this standard.
Annexes C, D and E are for information only.

– 7 –
127-6 ©IEC:1994
INTRODUCTION
According to the wish expressed by the users of miniature fuses, all standards, recommen-
dations and other documents relating to miniature fuses should have the same publication
number in order to facilitate reference to fuses in other specifications, for example,
equipment specifications.
Furthermore, a single publication number and subdivision into parts would facilitate the
establishment of new standards, because clauses and subclauses containing general
requirements need not be repeated.
The new IEC 127 series is thus subdivided as follows:
IEC 127: Miniature fuses (general title)
rt 1: Definitions for miniature fuses and general requirements for miniature
IEC 127-1, Pa
fuse-links
IEC 127-2, Part 2: Cartridge fuse-links
IEC 127-3, Pa rt 3: Sub-miniature fuse-links
IEC 127-4, Part 4: Universal modular fuse-links (UMF)
IEC 127-5, Part 5: Guidelines for quality assessment of miniature fuse-links
IEC 127-6, Pa rt 6: Fuse-holders for miniature cartridge fuse-links
IEC 127-7: (Free for further documents)
IEC 127-8: (Free for further documents)
IEC 127-9, Part 9: Test-holders and test circuits
IEC 127-10, Part 10: User guide
of IEC 127 covers requirements, test equipment and test methods for fuse-
This part
1 with regard to certain
holders. It is a self-standing document, which refers back to Pa rt
rts
definitions and the atmospheric conditions for test. It also makes reference to other pa
of IEC 127 with regard to dimensions and maximum power losses of fuse-links.

- 9 -
127-6 ©IEC:1994
MINIATURE FUSES —
Part 6: Fuse-holders for miniature cartridge fuse-links
1 Scope and object
1.1 This part of IEC 127 is applicable to fuse-holders for miniature cartridge fuse-links
according to IEC 127-2 and sub-miniature fuse-links according to IEC 127-3 for the protec-
rts thereof, normally
tion of electric appliances, electronic equipment and component pa
intended for use indoors. Examples of fuse-holder types with different features are given
in table 1.
- holders
Table 1 - Features of unexposed or exposed fuse
Types of mounting
1.1 Panel and base mounting
Printed circuit board mounting
1.2
2 Methods of fastening
Methods of fastening on panel:
2.1
2.1.1 Fixing nut fastening (threaded nut)
Snap-in fastening:
2.1.2
2.1.2.1 Fuse-base with an integral spring system
Fuse-base with a separate spring-nut (a nut fabricated, e.g. from thin spring steel
2.1.2.2
having an impression designed to accommodate the mating part)
Methods of fastening on printed circuit (PC) board:
2.2
2.2.1 Solder fastening
Plug-in fastening
2.2.2
3 Methods of insertion of the fuse-carrier into the fuse base
3.1 Screw insertion
3.2 Bayonet insertion
Plug-in insertion
3.3
4 Types of terminals
Screw terminals
4.1
4.2 Solder terminals
4.3 Quick connect terminals
4.4 Other solderless terminals: — crimp terminals
— wire wrap terminals
5 Protection against electric shock
5.1 Fuse-holder without integral protection against electric shock
5.2 Fuse-holder with integral protection against electric shock
Fuse-holder with enhanced integral protection against electric shock
5.3
NOTE — This list is not intended to be comprehensive and fuse-holders which are not listed are
not necessarily excluded from the scope.
This standard applies to fuse-holders with
a maximum rated current of 16 A and
-
- a maximum rated voltage of 1 500 V d.c. or 1 000 V a.c. and
- for use up to 2 000 m above sea-level, unless otherwise specified.

- 11 -
127-6 © IEC:1994
1.2 The object of this standard is to establish uniform requirements for safety and the
assessment of electrical, mechanical, thermal and climatic properties of fuse-holders and
the compatibility between fuse-holders and fuse-links.
2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this part of IEC 127. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
of IEC 127 are encouraged to investigate the possibility of
agreements based on this pa rt
applying the most recent editions of the normative documents indicated below. Members
of IEC and ISO maintain registers of currently valid International Standards.
International Electrotechnical Vocabulary (1EV) - Chapter 441:
IEC 50(441): 1984,
Switchgear, controlgear and fuses
IEC 50(581): 1978, International Electrotechnical Vocabulary (lEV) - Chapter 581:
Electromechanical components for electronic equipment
High-voltage test techniques - Part 1: General definitions and test
IEC 60-1: 1989,
requirements
rt 3: Measuring devices
IEC 60-3: 1976, High-voltage test techniques - Pa
4: Application guide for measuring
IEC 60-4: 1977, High-voltage test techniques - Pa rt
devices
Environmental testing - Part 1: General and guidance
IEC 68-1: 1988,
IEC 68-2: Environmental testing - Part 2: Tests
Environmental testing - Part 2: Tests - Tests A: Cold
IEC 68-2-1: 1990,
2: Tests - Tests B: Dry heat
IEC 68-2-2: 1974, Environmental testing - Part
Environmental testing - Part 2: Tests - Test Ca: Damp heat, steady
IEC 68-2-3: 1969,
state
IEC 68-2-6: 1982, Environmental testing - Part 2: Tests - Test Fc and guidance: Vibration
(sinusoidal)
rt 2: Tests - Test T: Soldering
IEC 68-2-20: 1979, Environmental testing - Pa
IEC 68-2-21: 1983, Environmental testing - Part 2: Tests - Test U: Robustness of termin-
ations and integral mounting devices
IEC 68-2-27: 1987, Environmental testing - Part 2: Tests - Test Ea and guidance: Shock
rt 2: Tests - Test XA and guidance:
IEC 68-2-45: 1980, Environmental testing - Pa
Immersion in cleaning solvents
Environmental testing - Part 2: Tests - Mounting of components,
IEC 68-2-47: 1982,
equipment and other articles for dynamic tests including shock (Ea), bump (Eb), vibration
(Fc and Fd) and steady-state acceleration and guidance

-13 -
127-6 ©IEC:1994
Method for determining the comparative and the proof tracking indices of
IEC 112: 1979,
solid insulating materials under moist conditions
Guide for the determination of thermal endurance properties of electrical
IEC 216-1: 1990,
1: General guidelines for ageing procedure and evaluation of
insulating materials - Part
test results
Test enclosures of non-injection type for constant relative humidity
IEC 260: 1968,
Fuse definitions
IEC 291: 1969,
IEC 291A: 1975, First supplement
rt 4: Protection for safety -
IEC 364-4-443: 1990, Electrical installations of buildings - Pa
Protection against over-
Chapter 44: Protection against overvoltages - Section 443:
voltages of atmospheric origin or due to switching
equipment; basic testing
Electromechanical components for electronic
IEC 512-8: 1993,
rt 8: Connector tests (mechanical) and
procedures and measuring methods - Pa
mechanical tests on contacts and terminations
IEC 529: 1989, Degrees of protection provided by enclosures (IP Code)
Classification of electrical and electronic equipment with regard to protec-
IEC 536: 1976,
tion against electric shock
Insulation co-ordination for equipment within low-voltage systems -
IEC 664-1: 1992,
Part 1: Principles, requirements and tests
2: Test methods - Section 2: Needle-flame
Fire hazard testing - Part
IEC 695-2-2: 1991,
test
Flat, quick-connect terminations
IEC 760: 1989,
Spring-operated impact-test apparatus and its calibration
IEC 817: 1984,
Connecting devices for low voltage circuits for household and similar
IEC 998-2-1: 1990,
2-1: Particular requirements for connecting devices as separate entities
rt
purposes - Pa
with screw-type clamping units
Preferred numbers - Series of preferred numbers
ISO 3: 1973,
Technical drawings - Method of indicating surface texture
ISO 1302: 1992,
3 Definitions
For the definitions of general terms used in this standard, reference should be made to
IEC 50(441) and IEC 50(581), International Electrotechnical Vocabulary (IEV), and to
IEC 664-1.
For definitions of terms relating to fuse-links, reference is made to IEC 127-1, IEC 291 and
IEC 291A.
For the purposes of this International Standard, the following definitions apply.

–15 –
127-6 ©IEC:1994
3.1 Fuse-holders
3.1.1 fuse-base: see 3.10 of IEC 127-1.
carrier: see 3.12 of IEC 127-1.
3.1.2 fuse-
see 3.9 of IEC 127-1.
3.1.3 fuse-holder:
A fuse-base with enclosed contacts, with or without a
unexposed fuse -holder:
3.1.4
fuse-carrier.
A fuse-base with exposed contacts (e.g. clips), with or
exposed fuse-holder:
3.1.5
without a fuse-carrier.
rating: see 3.16 of IEC 127-1.
3.2
The value of power dissipation assigned by the manu-
3.3 rated power acceptance:
facturer of the fuse-holder. it is intended to be the maximum power dissipation which the
fuse-holder can tolerate under specified test conditions without exceeding the specified
temperature.
The value of current assigned by the manufacturer of the fuse-holder
3.4 rated current:
and to which the rated power acceptance is referred.
The value of voltage assigned by the manufacturer of the fuse-holder
3.5 rated voltage:
to which operation and performance characteristics are referred.
The mutual correlation of insulation characteristics of elec-
insulation co-ordination:
3.6
trical equipment taking into account the expected micro-environment and other influencing
stresses.
The highest peak value of impulse voltage of prescribed
3.7 impulse withstand voltage:
form and polarity which does not cause breakdown under specified conditions.
A numeral defining a transient overvoltage condition.
3.8 overvoltage category:
Specified categories, see annex C.1.
Any addition of foreign matter, solid, liquid, or gaseous that can result in a
pollution:
3.9
rface resistivity of the insulation.
reduction of dielectric strength or su
A numeral characterizing the expected pollution of the micro-
3.10 pollution degree:
environment.
Specified degrees, see annex C.2.
The immediate environment of the insulation which
micro-environment:
3.11
particularly influences the dimensioning of the creepage distances.

- 17 -
127-6 ©IEC:1994
3.12 clearance: The shortest distance in air between two conductive pa rts.
The shortest distance along the su rface of an insulating
3.13 creepage distance:
material between two conductive pa rts.
Solid insulating material interposed between two conductive
3.14 solid insulation:
parts.
3.15 comparative tracking index (CTI): The test for comparative tracking index in
accordance with IEC 112 is designed to compare the pe rformance of various insulating
materials under test conditions, namely drops of an aqueous contaminant falling on a
horizontal su rface leading to electrolytic conduction.
Material groups and their CTI values, see annex C.3.
rt intended to be energized in normal use.
3.16 live part: A conductor or a conductive pa
or accessible su rface denotes a pa rt or su rface
3.17 accessible part: Accessible part
which can be touched by means of the standard test finger according to IEC 529, when the
fuse-holder is installed and operated as in normal use, e.g. on the front panel of
equipment.
holder electric shock protection categories: A designation characterizing
3.18 fuse-
the level of the protection against electric shock of a fuse-holder.
The highest air temperature that a fuse-
3.19 maximum ambient air temperature:
holder can endure at a power acceptance assigned by the manufacturer of the fuse-holder
without exceeding the maximum allowable temperatures on the accessible and
inaccessible su rfaces of the fuse-holder.
3.20 relative temperature index: Based on IEC 216-1, it is the temperature index of a
test material obtained from the time which corresponds to the known temperature index of
a reference material when both materials are subjected to the same ageing and diagnostic
procedures in comparative test.
3.21 Insulations
NOTE – For detailed information, see IEC 536 and IEC 664-1.
3.21.1 functional insulation: Insulation between conductive pa rts which is necessary
only for the proper functioning of the equipment.
3.21.2 Insulation applied to live parts to provide basic protection
basic insulation:
against electric shock.
NOTE – Basic insulation does not necessarily include insulation used exclusively for functional purposes.

127 -6 ©IEC:1994 - 19 -
3.21.3 supplementary insulation: Independent insulation applied in addition to basic
in event of a failure of
insulation in order to provide protection against electric shock the
basic insulation.
3.21.4 double insulation: Insulation comprising both basic insulation and supple-
mentary insulation.
3.21.5 reinforced insulation: A single insulation system applied to live parts, which
provides a degree of protection against electric shock equivalent to double insulation
under the conditions specified in the relevant IEC standard.
NOTE – A single insulation system does not imply that the insulation must be one homogeneous piece. It
may comprise several layers which cannot be tested singly as basic or supplementary insulation.
4 General requirements
Fuse-holders shall be so designed and constructed that in normal use, installed according
danger to the
to the manufacturer's instructions, their performance is reliable and without
user or surroundings.
by carrying out all of the relevant tests specified.
In general, compliance is checked
5 Preferred standard ratings and classifications for fuse-holders
Table 2 - Values for standard ratings and classifications
For fuse-links according to
Ratings
No .
Classifications
IEC 127-2 IEC 127-3
250 V 125 V and 250 V
5.1 Rated voltage
5.2 Rated current 6,3/10 A 5 A
5.3 Rated power acceptance at an ambient
1,6/2,5/4 W 1,6/2,5 W
air temperature of 23 °C
TAI
5.4 Maximum ambient air temperatures for:
5.4.1 accessible parts 40 °C
55 °C or 70 °C
5.4.2 inaccessible parts
Category PC1
5.5 Protection against electric shock
Category PC2
referring to fuse-holder
Category PC3
5.6 Protection against electric shock referring
Class I or II
to equipment, according to IEC 536
5.7 Insulation co-ordination according to
IEC 664-1
a) Overvoltage category Il or Ill
b) Pollution degree 2 or 3
c) Comparative tracking index CTI CTI >_ 150
NOTE – In reference to ratings (voltage, current, power acceptance), if other values are re-
quired, these values should be selected from the series R10 according to ISO 3. For classifi-
cations (Nos. 5.4, 5.5, 5.7), other values may be specified.

127-6 ©IEC:1994 – 21 –
6 Marking
Fuse-holders shall be marked with the name or trade mark of the manufacturer together
with the catalogue or type reference.
The manufacturer may provide additional markings for the rated voltage in volts, the power
250 V
acceptance in watts together with the rated current in amperes (. ./. .), e.g.
(4 W/6,3 A).
The additional marking shall not be placed on the front of the fuse-holder.
NOTE — This is to prevent installation of a replacement fuse-link with the wrong rating.
The marking shall be indelible and easily legible.
Compliance is checked by inspection and by the test according to 6.2 in IEC 127-1.
7 Information for the user of fuse-holders
Manufacturers shall hold available any information which is necessary for the correct
application of the fuse-holder.
See annex E.
8 General notes on tests
8.1 Nature of tests
Tests according to this standard are type tests.
It is recommended that, where acceptance tests are required, they are chosen from the
type tests in this standard.
Standard atmospheric conditions for measurement and tests
8.2
Unless otherwise specified, all tests shall be carried out under the atmospheric conditions
according to 7.1 in IEC 127-1.
8.3 Preconditioning of test samples
Unless otherwise specified, the test samples shall be maintained at standard atmospheric
conditions for not less than 4 h before measurements are performed.
8.4 Nature of supply
For a.c., the test voltage shall be of substantially sinusoidal form with a frequency
between 45 Hz and 62 Hz.
- 23 -
127-6 © IEC:1994
8.5 Gauges for tests
8.5.1 Gauges for fuse-links according to IEC 127-2
For tests that require gauges, the appropriate gauges mentioned in table 3 shall be used.
C
IEC 275/94
NOTE - The symbol for roughness is in accordance with ISO 1302.
Figure 1 - Outline of the gauges
Table 3 - Dimensions and materials for gauges for
fuse-links according to IEC 127-2
Weight
Type of cartridge
Materials of part
D2 B approxi-
L D1
fuse-link
Gauge mately I
T
Size C
No. g
mm mm mm mm
mm
5+0,1
+ 0,1 Steel e
1 max. 20,54 _ 4,2 -
5'3+0 01
0,04
+ 0'1
+00 ,04
5 0_0 01 4,2 ± 0,1 5 2,5 Brass2)
5 x 20 2 min. 19,46
Brass Glass or
+0,1 -
5,3+0,01
3 - 0 4 2 6,2
20,54 2 ►
-0,04 ceramic tube
end caps
+00 '01 + 0'1
4 max. 32,64_0,04 6,45 5,5±0,1 6 -
Steel
+00 '04 0'1
6,3 x 32 5 min. 30,96 6,25 0 01 5,5 ± 0,1 6+
Brass21
Glass or
Brass 8,3+0,1 -
6,45+0,01
2 1
6 - 32,64 0 5,5
0 end caps ceramic tube
-0,04 0
NOTE - All test gauges are without a melting element.
1) Hardened.
2)
Copper content from 58 % to 70 %.
The gauges or pa rts thereof made of brass shall be provided with 8 gm of nickel plating
plus 4,5 µm of gold plating.
There shall be no holes in the ends of the gauges.
The gauges shall have a homogeneous composition, except for gauge Nos. 3 and 6.

- 25 -
127-6 ©IEC:1994
8.5.2 Gauges for fuse-links with terminal pin diameters of (0,62 t 0,07) mm
according to IEC 127-3
For tests that require gauges, the appropriate gauges mentioned in table 4 shall be used.

0 10 max.
0 10 max.
IEC 277/94
IEC 276/94
Dimensions in millimetres
Dimensions in millimetres
Figure 2 - Outline of the gauges for fuse- Figure 3 - Outline of the gauges for fuse-
links according to standard
links according to standard
sheets 3 and 4
sheet 1
4 - Dimensions and materials for gauges for fuse-links
Table
according to IEC 127-3
Materials
Type of
D P of parts
sub-miniature
Gauge Size
fuse-link
mm A I B
No. mm
max. 0,70_2 ,02 Steels)
Standard
2 min. 0,55 0,02 2'54-0,09 Brass2)
sheet 1
0 Insulating
2)
Brass
0,70_0 02
3 —
material
0,70_2 .02
4 max. Steels)
Standard
0,55_2 5,08 ± 0,1
Brass2j
5 min.
sheets 3, 4
Insulating
Brass 2)
6 — 070 ,
material
2 02
NOTE — All test gauges are without a melting element.
1> Hardened.
2)
Copper content from 58 % to 70 %.

- 27 -
127-6 40 IEC:1994
The gauges or parts thereof made of brass shall be provided with 8 p.m of nickel plating
plus 4,5 gm of gold plating.
8.6 Type tests
The compliance of the fuse-holder with this standard shall be verified by means of type
tests.
The type tests required, the test sequences and the number of samples to be submitted
are stated in annex B.
9 Protection against electric shock
Category PC1: Fuse-holders without integral protection against electric shock
9.1
Fuse-holders of category PC1 are only suitable for applications where corresponding
additional means are provided to protect against electric shock.
Category PC2: Fuse-holders with integral protection against electric shock.
9.2
9.2.1 The fuse-holder shall be so designed that:
s are not accessible when the fuse-holder is properly assembled and
- live part
correctly installed on the front panel of equipment with fuse-carrier and gauge
No. 3 or No. 6 according to table 3 or 4 inserted into the fuse-base;
ion or removal of the fuse-
s do not become accessible, either during inse rt
- live pa rt
carrier by hand or with the aid of a tool or after the fuse-carrier has been removed.
9.2.2 Compliance is checked by using the standard test finger specified in IEC 529. This
test finger is applied without appreciable force in every possible position. Where the fuse-
holder has a fuse-carrier, gauge No. 3 or No. 6 according to table 3 or 4 shall be placed in
the fuse-carrier during testing. It is recommended that an electrical indicator with a voltage
rt .
of approximately 40 V is used for the indication of contact with the relevant pa
Category PC3: Fuse-holders with enhanced integral protection against electric shock
9.3
The requirements for this category are the same as those for 9.2 (Category PC2) with the
exception that the testing is carried out with a rigid test wire of 1 mm diameter according
to IEC 529, table VI, instead of the standard test finger.
10 Clearances and creepage distances
Clearances and creepage distances shall be checked for a fuse-holder properly assem-
bled and installed as in normal use, and fitted with gauge No. 3 or No. 6 according to
table 3 or 4.
Compliance is checked by measurement.

– 29 –
127-6 © IEC:1994
Minimum requirements for fuse-holders in respect to the grade of insulation
10.1
Table 5 – Types of insulation between different live parts and accessible pa rts
Type of insulation
Functional Basic Supplementary Reinforced Double
Insulation between:
X
a) Live parts of different
potential
b) Live parts and a metal mounting-
plate or any other metal parts
which may be in contact with the
mounting-plate e.g. base-fixing
devices.
Thickness of the mounting-plate
according to 11.1
– fuse-holders according to 10.1.1 X (X)*
X X
– fuse-holders according to 10.1.2
Live parts and all parts which may
c)
be touched with the test finger
(accessible parts)
X (X)*
– fuse-holders according to 10.1.1
X
– fuse-holders according to 10.1.2 X
Supplementary insulation is only applied in addition to basic insulation, whereas basic insulation
'
can be applied without supplementary insulation.
10.1.1 Fuse-holders intended for class I equipment shall have at least basic insulation
s shall be provided with
between live parts and accessible metal parts. These metal pa rt
means enabling a reliable connection to the protective earthing circuit of the equipment in
which it is intended to be used.
10.1.2 Fuse-holders intended for class II equipment shall have double or reinforced insu-
s and accessible pa rts.
lation between live pa rt
10.2 Clearances
Clearances shall be so dimensioned that the fuse-holder withstands the overvoltages
expected to occur during normal use. This is verified either by measurement of dimensions
or by impulse tests.
If electing to measure clearances, they should not be less than the values specified in
table 7A or table 7B.
e clearances, an impulse withstand voltage test
As an alternative to the measurement of th
according to 11.1.5 can be carried out. The required impulse voltage according to table 6
with regard to the rated voltage of the fuse-holder and the specified overvoltage category
shall be applied.
-31 -
127-6 © IEC:1994
Table 6 - Required impulse withstand voltage for clearances
Required impulse withstand voltage
1)
Rated voltage 0
1,2/50
V kV
Functional,
Overvoltage category
Reinforced
basic or
or double
supplementary
II Ill insulation
insulation
0,8
32 - 0,5
0,8 1,5
63 -
2,5
125 - 1,5
2,5 4,0
250 125
- 250 4,0 6,0
NOTE - There is increasing use of equipment operating at
voltages below 125 V. In order to conform with IEC 664-1, fuse-
holders specifically designed for these lower voltages should
meet the prescriptions in this table.
1)
According to IEC 60-1. defines the impulse wave
shape: 1,2 µs rise time and 50 µs half-value decay time.
NOTE - Attention is drawn to the fact that appliance specifications might contain requirements additional
to or deviating from those specified in tables 6, 7 and 8.
Tables 7A and 7B - Minimum clearances in air with regard to
the rated voltage, the overvoltage category
and the specified degree of pollution
NOTE - Minimum clearances in air in millimetres up to 2 000 m above sea-level for inhomogeneous field
conditions corresponding to IEC 664-1, table 2.
Table 7A - Overvoltage category Il
Clearances in air
Rated voltage
mm
V
Functional, basic Reinforced
Pollution degree
or
or supplementary
insulation double insulation 2 3
32 0,2 0,8
0,2 0,8
63 -
125 63 0,5 0,8
250 125 1,5 1,5
- 250 3,0 3,0
Table 7B - Overvoltage category Ill
Clearances in air
Rated voltage
mm
V
Functional, basic Reinforced
Pollution degree
or supplementary or
insulation double insulation 2 3
- 1,5 1,5
250 125 3,0 3,0
5,5 5,5
- 250
127-6 ©IEC:1994 – 33 –
10.3 Creepage distances
10.3.1 Creepage distances for basic or supplementary insulation, based on the rated
voltage shall be selected from table 8. The following influencing factors shall be taken into
account:
rated voltage;
– pollution degree;
- shape of insulating surface;
- comparative tracking index (CTI).
10.3.2 Measurement of creepage distances and clearances, shape of insulating surface:
requirements according to 4.2 in IEC 664-1.
10.3.3 Creepage distances for reinforced or double insulation:
twice the value as specified in table 8.
10.3.4 A creepage distance cannot be less than the associated clearance so that the
shortest creepage distance possible is equal to the required clearance.
Table 8 – Minimum creepage distances in millimetres for a micro-environment
dependent on rated voltage, pollution degree, insulating material,
corresponding to IEC 664-1, table 4
Creepage distances
mm
Rated
Pollution degree Pollution degree
voltage
2 3
e Material groupe
Material group
V
I Il Illa I Illb I Il Illa I Illb
32 0,53 0,53 0,53 1,3 1,3 1,3
1,6 1,8
63 0,63 0,9 1,25 2,0
125 1,5 1,9 2,1
0,75 1,05 2,4
250 1,25 1,8 2,5 3,2 3,6 4,0
NOTE — There is increasing use of equipment operating at voltages below 125 V. In order
to conform with IEC 664-1, fuse-holders specifically designed for these lower voltages
should meet the prescriptions in this table.
1) See annex C.
11 Electrical requirements
11.1 Insulation resistance, dielectric strength and impulse withstand voltage
11.1.1 Mounting
a) Fuse-holders designed for panel or base mounting, shall be mounted on a metal
plate, with a thickness s (figure 4) specified by the manufacturer. A test gauge
according to table 9 and with or without the fuse-carrier shall be inserted into the fuse-
base.
– 35 –
127-6 © I EC:1994
For fuse-holders having screw-in fuse-carriers, these carriers shall be fitted in the
normal way for each operation with a torque equal to two-thirds of the value specified in
table 10.
b) Fuse-holders designed for PC board mounting shall be mounted on a test PC board
according to annex A and, if adapted to such use, with a front-panel metal plate of a
thickness s (figure 5). A test gauge according to table 9 and with or without the fuse-
carrier shall be inserted into the fuse-base.
Fuse-holders for PC board mounting by soldering (through-hole types) should have a
pin-spacing of n e.
11.1.2 Humidity preconditioning
Mounted fuse-bases according to 11.1.1 and separate, not inserted fuse-carriers are sub-
mitted to the humidity preconditioning.
The humidity preconditioning is carried out in a humidity chamber containing air with a
relative humidity maintained between 91 % and 95 %.
The air in the chamber where test samples are located shall be maintained at a tempera-
ture t = (40 ± 2) °C, uniformly distributed throughout the chamber.
The air in the chamber shall be stirred and the chamber shall be designed so that mist of
condensed water will not precipitate on the test samples. Temperature variations shall not
of the test samples to reach a dew-point condition. Some methods of
allow any pa rt
achieving the specified relative humidity are described in IEC 260.
The test samples are kept in the chamber for 48 h.
Immediately after the humidity preconditioning, with the samples still in the humidity
chamber or in the room in which the samples were brought to the prescribed temperature,
the measurement of the insulation resistance and dielectric strength are made, after
s which were separated before the humidity preconditioning.
reassembly of those pa rt
s of insulating material shall be wrapped in metal foil as shown in figures 4 and 5.
Part
Measurement of insulation resistance
11.1.3
The insulation resistance shall be measured between the points as specified in table 9.
D.C. voltage according to table 9 shall be applied. The measurement is made 1 min after
application of the test-voltage.
The insulation resistance shall be not less than the values shown in table 9.
11.1.4 Dielectric strength test
Immediately after the measurement of the insulation resistance, with the samples still in
the humidity chamber or in the room in which the samples were brought to the prescribed
temperature, an a.c. voltage according to table 9 is applied for 1 min between the points
specified in table 9.
- 37 -
127-6 ©IEC:1994
Initially, not more than half the prescribed voltage is applied, then it is raised rapidly to the
full value.
No flashover or breakdown shall occur during the test.
11.1.5 Impulse withstand voltage test
After the test in 11.1.4 the impulse withstand voltage shall be tested between the points as
specified in table 9.
The required impulse withstand voltage according to table 6 shall be applied.
Form and numbers of impulses:
The 1,2/50 µs impulse voltage shall be applied three times for each polarity at intervals
of 1 s minimum.
NOTES
the impulse generator should not be higher
of
1 Unless otherwise specified, the output impedance
than 500 S2.
test equipment, see IEC 60-1, IEC 60-3 and 60-4.
2 Description of
During this voltage test, no breakdown or flashover shall occur.
Corona effects and similar phenomena are disregarded.
11.2 Contact resistance
General measuring requirements
11.2.1
Measurements may be carried out with direct current or alternating current. For
a.c. measurements the frequency shall not exceed 1 kHz. In the case of dispute, the d.c.
measurements shall govern.
The accuracy of the measuring apparatus shall be within ±3 %.
For fuse-holders having screw-in fuse-carriers these carriers shall be fitted in the normal
way for each operation with a torque equal to two-thirds of the value specified in table 10.
The contact resistance shall be measured between the terminals after the fuse-holder has
been equipped with a gauge No. 2 or No. 5 according to table 3 or 4.
Contact resistance of fuse-holders intended for PC board mounting shall be measured on
a fuse-holder mounted (soldered) on a test PC board according to annex A. The voltage
drop shall be measured between points P and O of the figure in annex A.
The contact resistance shall normally be calculated from the voltage drop measured
between the terminals.
127-6 ©IEC:1994 - 39 -
The measurement is carried out under the following conditions.
Test voltage: the electromotive force of the source shall not exceed 60 V d.c. or a.c.
a)
(peak), but shall be at least 10 V.
b) Test current: 0,1 A
c) Measurement shall be made within 1 min after the application of the test current.
Care shall be taken during the measurement to avoid exerting abnormal pressure
d)
on the contacts under test and to avoid movement of the test cable.
11.2.2 Measuring cycle
11.2.2.1 Measuring cycle with d.c.
One measuring cycle consists of:
ion of the gauge in the fuse-holder;
a) inse rt
b) measurement with current flowing in one direction;
measurement with current flowing in opposite direction;
c)
d) removal of the gauge from the fuse-holder.
11.2.2.2 Measuring cycle with a.c.
One measuring cycle consists of:
ion of the gauge in the fuse-holder;
a) inse rt
b) measurement;
removal of the gauge from the fuse-holder.
c)
11.2.3 Measurement and requirements
The complete measurement shall consist of five measuring cycles, which shall be carried
out in immediate succession.
The average of the values of the contact resistance shall not exceed 5 ma The value of
any individual measurement shall not exceed 10 mfl.

127-6 ©IEC:1994 - 41 -
fd d
OJ d
Fuse-carrier
Metal foil
Illllll^llllllliii^^
=iv Ammosir^^i
IEC 279/94
IEC 278194
NOTE – Thickness s to be specified by the manufacturer.
Figure 4 - Panel mounting Figure 5 - PC board mounting

Table 9 — Values for insulation resistance, dielectric strength and impulse withstand voltage
Insulation resistance Dielectric strength Impulse withstand voltage
DC test voltage
AC test voltage Impulse test voltage
Number
Insulation resistance,
of test gauges Rated Insulation
V
dielectric strength and V V
according voltage resistance
impulse withstand voltage
to table 3
functional,
functional, functional,
measured between:
reinforced Mfg reinforced reinforced
or 4
V basic or
basic or basic or
or double
or double or double
supplementary
supplementary supplementary
insulation insulation insulation
insulation
insulation insulation
1 Unexposed fuse-holder 32
Under consideration
1.1 The terminals 3 / 6
1.2 The terminals and the 1 / 4
metal mounting or front-
panel plate
1.3 The terminals and any other
metal parts which may be in
contact with the mounting
plate, e.g. base fixing 125
Twice rated voltage 210 for Twice rated
Twice the Required impulse with-
devices
but at least 100 V functional,
voltage value for stand voltage values
basic or
+1 000 V functional, according to table 6
supplementary
basic or
1.4 The terminals and a metal 250
insulation
supplementary
foil covering the whole of
insulation
the accessible surface
(See figures 4 and 5)
220 for
reinforced
or double
insulation
2 Exposed fuse-holder
2.1 The terminals 3 / 6
The terminals and the 1 / 4
2.2
mounting plate
NOTE – There is increasing use of equipment operating at voltages below 125 V. In order to conform with IEC 664-1, fuse-holders specifically designed for these
lower voltages should meet the prescriptions in this table.

– 45 –
127-6 © IEC:1994
12 Mechanical requirements
Fuse-holders shall have adequate mechanical strength to withstand the stresses imposed
during installation and use.
Compliance is checked by the appropriate tests of 12.1 to 12.7 as follows.
12.1 Mounting
For the tests of 12.2 to 12.4 the fuse-holders are mounted as follows.
a) Fuse-holders designed for front-panel mounting shall be mounted with their fixing
elements, if any, in the centre of a metal plate 130 mm x 130 mm having a maximum
as specified by the manufacturer.
thickness s
having a free space with
The specimen as a whole is then fixed to a rigid plane suppo rt
a diameter of 100 mm for the base of a panel-mounted fuse-holder. To ensure that the
specimen is rigidly supported, a block of metal or concrete having a mass of 15 kg shall
be used (figure 6).
Any fixing nut or fixing screw is screwed on with two-thirds of the torque specified in
table 11 or 12 as applicable.
Metal plate
//lllllillll►\
smi
iiïiiiiiiiiii iIll iiiiiiiiiiiii
IIIIIIIII. NM
o
^
Metal or concrete
Al m
block with a mass
a^
of 15 kg
II
IEC 280/94
Dimensions in millimetres
Figure 6 – Test device for mechanical test
b) Fuse-holders designed for PC board mounting shall be mounted on a test PC board
according to annex A and according to the manufacturer's instructions.
Compatibility between fuse-holder and fuse-link
12.2
The maximum gauge No. 1 or No. 4 according to table 3 or 4 shall be inserted in and with-
drawn from the fuse-holder and fuse-carrier, if any, 10 times.

127-6 ©IEC:1994 – 47 –
For fuse-holders having screw-in fuse-carriers, these carriers shall be fitted in the normal
way for each operation with a torque equal to two-thirds of the value specified in table 10.
There shall be no visible damage or loosening of parts. In the most unfavourable position,
the minimum gauge No. 2 or 5 according to table 3 or 4 shall not fall from the fuse-carrier.
The minimum gauge No. 2 or No. 5 according to table 3 or 4 shall then be inserted in the
holder and the contact resistance shall be measured according to 11.2 with the same
requirements.
12.3 Mechanical strength of the connection between fuse-base and fuse-carrier
12.3.1 Screw and bayonet connections
For the following tests, the fuse-carrier together with the maximum gauge No. 1 or No. 4
according to table 3 shall be inserted in the fuse-base, mounted on a metal plate.
a) Torque test on fuse-carriers
The fuse-carrier shall be subjected five times to the appropriate torque specified in
table 10.
b) Tensile test on fuse-carriers
The screw-in fuse-carrier is screwed in with a torque of two-thirds of the value as
specified in table 10.
The screw-in or bayonet fuse-carrier shall then be subjected for 1 min to an axial pull
as specified in table 10.
Table 10 – Values for torque and axial pull
Axial pull
Torque
Diameter of fuse-carrier
(0 d in figures 4 and 5)
Nm N
0,4 25
Up to and including 16 mm
Over 16 mm, up to and including 25 mm 0,6 50
During and after the tests, the fuse-carrier must be securely held in the fuse-base and
shall not show any change impairing its further use.
For fuse-holders where fuse-carriers are flush with the fuse-base, the axial pull test is not
required.
12.3.2 Plug-in connection
Insertion and withdrawal forces:
The fuse-carrier together with the maximum gauge No. 1 or No. 4 according to table 3
shall be inserted in and withdrawn from the fuse-base. The forces have to be measured
with suitable measuring devices. This test has to be repeated 10 times. The value of any
individual measurement, insertion and withdrawal forces, shall be within limits assigned by
the manufacturer.
127-6 ©IEC:1994 –49
After the test the contact resistance shall be measured according to 11.2 with the same
requirements.
12.4 Impact test
This test shall only be applied to panel-mounted fuse-holders. The fuse-carrier with the
maximum gauge No. 1 or
...