EN 60127-3:1996
(Main)Miniature fuses - Part 3: Sub-miniature fuse-links
Miniature fuses - Part 3: Sub-miniature fuse-links
This standard relates to special requirements applicable to sub-miniature fuse-links adapted to printed circuits and used for the protection of electric appliances, electronic equipment and component parts thereof, normally intended to be used indoors. This standard also applies to the requirements of EN 60127-1.
Geräteschutzsicherungen - Teil 3: Kleinstsicherungseinsätze
Coupe-circuit miniatures - Partie 3: Eléments de remplacement subminiatures
S'applique aux prescriptions particulières applicables à tous les modèles d'éléments de remplacement subminiatures adaptés aux circuits imprimés et employés pour la protection d'appareils électriques, de matériels électroniques et de leurs éléments constituants, normalement destinés à être utilisés à l'intérieur. Renvoie en outre aux prescriptions de la EN 60127-1.
Miniaturne varovalke - 3. del: Subminiaturni taljivi vložki (IEC 60127-3:1988+A1:1991) (vsebuje popravek AC:1996)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-1999
Nadomešča:
SIST EN 60127-3:1995
Miniaturne varovalke - 3. del: Subminiaturni taljivi vložki (IEC 60127-
3:1988+A1:1991) (vsebuje popravek AC:1996)
Miniature fuses -- Part 3: Sub-miniature fuse-links
Geräteschutzsicherungen -- Teil 3: Kleinstsicherungseinsätze
Coupe-circuit miniatures -- Partie 3: Eléments de remplacement subminiatures
Ta slovenski standard je istoveten z: EN 60127-3:1996
ICS:
29.120.50 Varovalke in druga Fuses and other overcurrent
nadtokovna zaščita protection devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
NORME CEI
INTERNATIONALE IEC
127-3
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
Coupe-circuit miniatures
Troisième partie:
Eléments de remplacement subminiatures
Miniature fuses
Part 3:
Sub-miniature fuse-links
© CEI 1988 Droits de reproduction réservés —
Copyright — all rights reserved
Aucune partie de cette publication ne peut être reproduite ni
No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun pro-
any form or by any means, electronic or mechanical,
cédé, électronique ou mécanique, y compris la photocopie et including photocopying
and microfilm, without permission
les microfilms, sans l'accord écrit de l'éditeur.
in writing from the publisher.
Bu
reau Central de la Commission Electrotechnique Inte rnationale 3, rue de Varembé
Genève, Suisse
Commission Electrotechnique Internationale
CODE PRIX
International Electrotechnical Commission
PRICE CODE
IEC
Mewayaapopttaa 3nelcrporexHu ecaaa HoMUCCHR
• • Pour prix, voir catalogue en vigueur
For price, see current catalogue
127-3 (2) © IEC — 3 —
CONTENTS
Page
FOREWORD 5
PREFACE 5
INTRODUCTION 7
SECTION ONE — ADDITIONAL REQUIREMENTS AND TEST EQUIPMENT
Clause
1. Scope
2. Object
3. Definitions
4. General requirements
Standard ratings 9
5.
6. Marking 9
7. General notes on tests 9
8. Dimensions and construction
9. Electrical requirements
TABLE 1 15
TABLE 2 17
FIGURES 18
STANDARD SHEETS
SECTION Two —
Standard Sheet 1 — Sub-miniature fuse-links
Quick-acting, low breaking capacity 25
Standard Sheet 2 — Sub-miniature fuse-links
Quick-acting, low breaking capacity
Standard Sheet 3 — Sub-miniature fuse-links
Quick-acting, low breaking capacity 33
Standard Sheet 4 Sub-miniature fuse-links
—
Time lag, low breaking capacity 37
127-3 (2) © IEC — 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
MINIATURE FUSES
Part 3: Sub-miniature fuse-links
FOREWORD
1) The formal decisions or agreements of the I EC 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 inte rnational consensus of opinion
on the subjects dealt with.
2) They have the form of recommendations for inte rnational use and they are accepted by the National Committees in that
sense.
3) In order to promote inte rnational unification, the IEC expresses the wish that all National Committees should adopt the text of
the I EC recommendation for their national rules in so far as national conditions will permit. Any divergence between the I EC
recommendation and the corresponding national rules should, as far as possible, be clearly indicated in the latter.
PREFACE
This standard has been prepared by Sub-Committee 32C: Miniature Fuses, of I EC Technical Com-
mittee No. 32: Fuses.
The text of this standard is based upon the following documents:
Six Months' Rule Report on Voting
32C(CO)49 32C(CO)58
Full information on the voting for the approval of this standard can be found in the Voting Repo rt
indicated in the above table.
The following IEC publications are quoted in this standard:
Publications Nos. 68-2-20 (1979): Basic Environmental Testing Procedures, Pa rt 2: Tests — Test T: Soldering.
68-2-21 (1983): Test U: Robustness of Terminations and Integral Mounting Devices.
695: Fire Hazard Testing.
127-3(2)©IEC — 7
MINIATURE FUSES
Part 3: Sub-miniature fuse-links
INTRODUCTION
The users of miniature fuses express the wish that all standards, recommendations and other docu-
ments relating to miniature fuses should have the same publication number in order to facilitate reference
to fuses in other specifications, e.g. equipment specifications.
Furthermore a single publication number and subdivision into pa rts would facilitate the establishment
of new standards, because paragraphs containing general requirements need not be repeated.
The new I EC Publication 127 series is intended to be subdivided as follows:
Publications Nos 127: Miniature fuses (general title)
127-1: Part
1: Definitions for miniatures fuses and general requirements for miniatures fuse-links.
127-2: Part
2: Cartridge fuse-links.
127-3: Part 3: Subminiature fuse-links.
127-4: Part
4: Universal modular fuse-links.
127-5: Part
5: Guidelines for quality assessment of miniature fuse-links.
127-6: Pa
rt 6: Fuse-holders (until now I EC 257).
127-7: (free for further documents).
127-8: (free for further documents).
127-9: Pa
rt 9: Test-holders and test-circuits.
127-10: Part 10: User guide.
The third pa
rt
of this standard covers additional requirements, test equipment and Standard Sheets.
SECTION ONE — ADDITIONAL REQUIREMENTS AND TEST EQUIPMENT
1. Scope
This standard relates to special requirements applicable to sub-miniature fuse-links adapted to
printed circuits and used for the protection of electric appliances, electronic equipment and com-
ponent part
s thereof, normally intended to be used indoors.
It does not apply to sub-miniature fuse-links for appliances intended to be used under special
conditions, such as in a corrosive or explosive atmosphere.
Note. —
Electrical and electronic circuit designers and printed circuit board manufacturers are advised to allow a 10 mm cube
space for all sub-miniature fuse-links.
This standard applies in addition to the requirements of Pa
rt 1.
2. Object
The object of this standard is:
To define special and additional test methods for sub-miniature fuse-links applying in addition to
the requirements of Part 1.
3. Definitions
(see Part 1)
127-3 (2) ©I EC
4. General requirements (see Part 1)
5. Standard ratings (see Part 1)
6. Marking
1 the following criterion is to be
Additionally to the requirements of Clause 6 in Pa rt
observed:
6.4 The values for "d" and "s" are given in the relevant Standard Sheet.
7. General notes on tests
1 the following criteria are to be
Additionally to the requirements of Clause 7 in Part
observed:
7.2.1 The number of sub-miniature fuse-links required in the case of sub-miniature fuse-links in
accordance with Standard Sheets 1 and 2 is 66, of which 12 are kept as spares in case some of the
tests have to be repeated. The number of sub-miniature fuse-links required in the case of sub-
miniature fuse-links in accordance with Standard Sheets 3 and 4 is 51, of which 12 are kept as spares
in case some of the tests have to be repeated.
1, sub-miniature fuse-links shall be
Additionally to the test mentioned in Sub-clause 7.2.1 of Pa rt
taken and shall be tested or inspected in accordance with the following sub-clause:
•
5. Sub-miniature fuse-link terminations (Sub-clause 8.3)
7.3 Fuse-bases for testing
For tests that require a printed wiring board for mounting and connection of the sub-miniature
fuse-link, a standard test board as shown in Figure 1, page 18, shall be used. This standard printed
wiring board shall be mounted on the standard test base of Figure 2, page 19. The base material for
the board shall be phenolic cellulose paper, copperclad, laminated sheet.
The nominal sheet thickness shall be 1.6 mm.
The nominal thickness of the copper layer shall be 0.035 mm.
Metal pa s of the fuse-base shall be made of brass with copper content between 58% and 70%.
rt
Contact parts shall be silver-plated.
When two or more sub-miniature fuse-links are tested in series, the fuse-bases shall be located so
that there will be a spacing of not less than 50 mm between any two sub-miniature fuse-links under
test. The conductor connecting the fuse-bases together and connecting the fuse-bases to the
ammeter and the source of supply shall be insulated copper wire. The length of each conductor shall
be 250 mm and the diameter of the wire shall be approximately 0.64 mm.
ion of
Note. — Fuse-bases for testing having equivalent electrical and thermal properties and providing for quick inse rt
sub-miniature fuse-links are under consideration.
7.4 Schedule for testing sub-miniature fuse-links according to Standard Sheets 1 and 2, Table 1, page 15,
and according to Standard Sheets 3 and 4, Table 2, page 17.
8. Dimensions and construction
Additionally to the requirements of Clause 8 in Part 1 the following criteria are to be
observed:
127-3 (2) © IEC — 1.1 —
8.2 Construction
The sub-miniature fuse-link shall be resistant to heat according to Sub-clause 9.7 of Part 1 and to
fire in accordance with I E C Publication 695.
Compliance is checked by inspection.
This st
andard is based on the assumption that the case of the sub-miniature fuse-link is made of
glass, ceramic or similar non-combustible material. For other material, such as the optional insu-
lating sleeve or epoxy coating or similar material shown on Standard Sheet 2, additional tests are
under consideration.
8.3 Sub-miniature fuse-link terminations
The sub-miniature fuse-link terminations should be firmly attached so that it is not possible to
remove them without damaging the sub-miniature fuse-link.
The samples are pre-conditioned by immersion in water for 24 h at a temperature between 15 °C
and 35 °C.
Terminations shall withstand the mechanical forces likely to be encountered during normal use.
With the sub-miniature fuse-link held in a fixed position, each terminal in turn is subjected at
ambient temperature to the forces laid down in this standard. These forces shall be exerted in the
direction of the axis of the terminal and applied progressively without jerks. Test sample groups
shall be equally divided among the specific termination tests stipulated in the relevant Standard
Sheets.
Present test methods are to be performed in accordance with I EC Publication 68-2-21.
— For the tensile test (Ua l
), the force applied shall be 10 N.
—
For the thrust test (Ua 2), the force applied shall be 2 N.
—
For the bending test (Ub), if applicable, the force applied shall be 5 N and the number of bends
shall be one.
At the conclusion of testing, the sub-miniature fuse-link terminations shall remain firmly
attached and the voltage drop shall not exceed the maximum allowed in the relevant Standard
Sheet.
8.4 Termination configuration
The sub-miniature fuse-link terminations shall be designed to permit easy installation on printed
circuit wiring boards having a grid system of holes located on 2.54 mm centres, or into fuse-bases
having a spacing between the terminations which is compatible with the 2.54 mm grid system.
Note. —
Electrical and electronic circuit designers are advised to note that grid systems for holes located on 2.54 mm centres
may result in spacings between conductive tracks, in some applications, which do not provide sufficient creepage or
clearance for open-circuit conditions. In such circumstances, it may be necessary to modify the land area around the
mounting hole to ensure an acceptable minimum distance between conductive tracks or select a sub-miniature
fuse-link with longer terminations which can be formed to fit into hole spacings offering the necessary degree of
protection.
More details are given in the User Guide (under consideration as Pa rt 10).
9. Electrical requirements
Additionally to the requirements of Clause 9 in Pa rt 1 the following criteria are to be
observed:
9.1 Voltage drop
The use of a high impedance voltmeter is recommended for measuring the voltage drop. Voltage
drop shall be measured at the points marked with U in Figure 1, page 18.
127-3 (2) © I EC — 13 —
Breaking capacity
9.3
9.3.1 Additionally to the requirements of Sub-clause 9.3.1 in Pa rt 1 the following is to be observed:
Typical test circuits for a.c. and d.c. are given in Figure 3, page 20.
When alternating current is stipulated by the relevant Standard Sheets, the circuit power factor
shall be larger than 0.95. To obtain this result, the circuit current shall be adjusted by the use of
resistors with negligible inductance.
9.3.2 In addition to the criteria of failure prescribed in Part 1, in each of the tests, the sub-miniature
fuse-link shall operate satisfactorily without any of the following phenomena:
—
fusing together of the contacts or terminations;
—
illegibility of marking after test;
— piercing of the external surfaces visible to the naked eye.
The following phenomena are neglected:
— black spots on the sub-miniature fuse-link terminations;
— small deformations of the sub-miniature fuse-link terminations;
— cracking of the subminiature fuse-link.
Endurance tests
9.4
9.4.1 Endurance test at normal ambient temperature
Compliance is checked by subjecting the sub-miniature fuse-links to test method A or B as
required in the relevant Standard Sheets.
9.4.2 Test method A
As specified in Part 1, Sub-clause 9.4 a) to d).
9.4.3 Test method B
a) A direct current, specified in the relevant Standard Sheet, is passed through the sub-miniature
fuse-link for a period of 100 h. The current stability during the test shall be maintained within
± 1% of the adjustable value.
b) Finally, the voltage drop across the fuse-link is measured again according to Sub-clause 9.1. The
voltage drop across the fuse-link after the test shall not have increased by more than 10% of th e
value measured before the test. - -
c) After the tests, the marking shall still be legible and soldered joints on end caps etc. shall not
show any appreciable deterioration.
(under consideration)
9.8 Additional tests
Additional tests under consideration including en
...
SLOVENSKI STANDARD
01-julij-1999
1DGRPHãþD
SIST EN 60127-3:1995
Miniaturne varovalke - 3. del: Subminiaturni taljivi vložki (IEC 60127-
3:1988+A1:1991) (vsebuje popravek AC:1996)
Miniature fuses -- Part 3: Sub-miniature fuse-links
Geräteschutzsicherungen -- Teil 3: Kleinstsicherungseinsätze
Coupe-circuit miniatures -- Partie 3: Eléments de remplacement subminiatures
Ta slovenski standard je istoveten z: EN 60127-3:1996
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
127-3
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
Coupe-circuit miniatures
Troisième partie:
Eléments de remplacement subminiatures
Miniature fuses
Part 3:
Sub-miniature fuse-links
© CEI 1988 Droits de reproduction réservés —
Copyright — all rights reserved
Aucune partie de cette publication ne peut être reproduite ni
No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun pro-
any form or by any means, electronic or mechanical,
cédé, électronique ou mécanique, y compris la photocopie et including photocopying
and microfilm, without permission
les microfilms, sans l'accord écrit de l'éditeur.
in writing from the publisher.
Bu
reau Central de la Commission Electrotechnique Inte rnationale 3, rue de Varembé
Genève, Suisse
Commission Electrotechnique Internationale
CODE PRIX
International Electrotechnical Commission
PRICE CODE
IEC
Mewayaapopttaa 3nelcrporexHu ecaaa HoMUCCHR
• • Pour prix, voir catalogue en vigueur
For price, see current catalogue
127-3 (2) © IEC — 3 —
CONTENTS
Page
FOREWORD 5
PREFACE 5
INTRODUCTION 7
SECTION ONE — ADDITIONAL REQUIREMENTS AND TEST EQUIPMENT
Clause
1. Scope
2. Object
3. Definitions
4. General requirements
Standard ratings 9
5.
6. Marking 9
7. General notes on tests 9
8. Dimensions and construction
9. Electrical requirements
TABLE 1 15
TABLE 2 17
FIGURES 18
STANDARD SHEETS
SECTION Two —
Standard Sheet 1 — Sub-miniature fuse-links
Quick-acting, low breaking capacity 25
Standard Sheet 2 — Sub-miniature fuse-links
Quick-acting, low breaking capacity
Standard Sheet 3 — Sub-miniature fuse-links
Quick-acting, low breaking capacity 33
Standard Sheet 4 Sub-miniature fuse-links
—
Time lag, low breaking capacity 37
127-3 (2) © IEC — 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
MINIATURE FUSES
Part 3: Sub-miniature fuse-links
FOREWORD
1) The formal decisions or agreements of the I EC 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 inte rnational consensus of opinion
on the subjects dealt with.
2) They have the form of recommendations for inte rnational use and they are accepted by the National Committees in that
sense.
3) In order to promote inte rnational unification, the IEC expresses the wish that all National Committees should adopt the text of
the I EC recommendation for their national rules in so far as national conditions will permit. Any divergence between the I EC
recommendation and the corresponding national rules should, as far as possible, be clearly indicated in the latter.
PREFACE
This standard has been prepared by Sub-Committee 32C: Miniature Fuses, of I EC Technical Com-
mittee No. 32: Fuses.
The text of this standard is based upon the following documents:
Six Months' Rule Report on Voting
32C(CO)49 32C(CO)58
Full information on the voting for the approval of this standard can be found in the Voting Repo rt
indicated in the above table.
The following IEC publications are quoted in this standard:
Publications Nos. 68-2-20 (1979): Basic Environmental Testing Procedures, Pa rt 2: Tests — Test T: Soldering.
68-2-21 (1983): Test U: Robustness of Terminations and Integral Mounting Devices.
695: Fire Hazard Testing.
127-3(2)©IEC — 7
MINIATURE FUSES
Part 3: Sub-miniature fuse-links
INTRODUCTION
The users of miniature fuses express the wish that all standards, recommendations and other docu-
ments relating to miniature fuses should have the same publication number in order to facilitate reference
to fuses in other specifications, e.g. equipment specifications.
Furthermore a single publication number and subdivision into pa rts would facilitate the establishment
of new standards, because paragraphs containing general requirements need not be repeated.
The new I EC Publication 127 series is intended to be subdivided as follows:
Publications Nos 127: Miniature fuses (general title)
127-1: Part
1: Definitions for miniatures fuses and general requirements for miniatures fuse-links.
127-2: Part
2: Cartridge fuse-links.
127-3: Part 3: Subminiature fuse-links.
127-4: Part
4: Universal modular fuse-links.
127-5: Part
5: Guidelines for quality assessment of miniature fuse-links.
127-6: Pa
rt 6: Fuse-holders (until now I EC 257).
127-7: (free for further documents).
127-8: (free for further documents).
127-9: Pa
rt 9: Test-holders and test-circuits.
127-10: Part 10: User guide.
The third pa
rt
of this standard covers additional requirements, test equipment and Standard Sheets.
SECTION ONE — ADDITIONAL REQUIREMENTS AND TEST EQUIPMENT
1. Scope
This standard relates to special requirements applicable to sub-miniature fuse-links adapted to
printed circuits and used for the protection of electric appliances, electronic equipment and com-
ponent part
s thereof, normally intended to be used indoors.
It does not apply to sub-miniature fuse-links for appliances intended to be used under special
conditions, such as in a corrosive or explosive atmosphere.
Note. —
Electrical and electronic circuit designers and printed circuit board manufacturers are advised to allow a 10 mm cube
space for all sub-miniature fuse-links.
This standard applies in addition to the requirements of Pa
rt 1.
2. Object
The object of this standard is:
To define special and additional test methods for sub-miniature fuse-links applying in addition to
the requirements of Part 1.
3. Definitions
(see Part 1)
127-3 (2) ©I EC
4. General requirements (see Part 1)
5. Standard ratings (see Part 1)
6. Marking
1 the following criterion is to be
Additionally to the requirements of Clause 6 in Pa rt
observed:
6.4 The values for "d" and "s" are given in the relevant Standard Sheet.
7. General notes on tests
1 the following criteria are to be
Additionally to the requirements of Clause 7 in Part
observed:
7.2.1 The number of sub-miniature fuse-links required in the case of sub-miniature fuse-links in
accordance with Standard Sheets 1 and 2 is 66, of which 12 are kept as spares in case some of the
tests have to be repeated. The number of sub-miniature fuse-links required in the case of sub-
miniature fuse-links in accordance with Standard Sheets 3 and 4 is 51, of which 12 are kept as spares
in case some of the tests have to be repeated.
1, sub-miniature fuse-links shall be
Additionally to the test mentioned in Sub-clause 7.2.1 of Pa rt
taken and shall be tested or inspected in accordance with the following sub-clause:
•
5. Sub-miniature fuse-link terminations (Sub-clause 8.3)
7.3 Fuse-bases for testing
For tests that require a printed wiring board for mounting and connection of the sub-miniature
fuse-link, a standard test board as shown in Figure 1, page 18, shall be used. This standard printed
wiring board shall be mounted on the standard test base of Figure 2, page 19. The base material for
the board shall be phenolic cellulose paper, copperclad, laminated sheet.
The nominal sheet thickness shall be 1.6 mm.
The nominal thickness of the copper layer shall be 0.035 mm.
Metal pa s of the fuse-base shall be made of brass with copper content between 58% and 70%.
rt
Contact parts shall be silver-plated.
When two or more sub-miniature fuse-links are tested in series, the fuse-bases shall be located so
that there will be a spacing of not less than 50 mm between any two sub-miniature fuse-links under
test. The conductor connecting the fuse-bases together and connecting the fuse-bases to the
ammeter and the source of supply shall be insulated copper wire. The length of each conductor shall
be 250 mm and the diameter of the wire shall be approximately 0.64 mm.
ion of
Note. — Fuse-bases for testing having equivalent electrical and thermal properties and providing for quick inse rt
sub-miniature fuse-links are under consideration.
7.4 Schedule for testing sub-miniature fuse-links according to Standard Sheets 1 and 2, Table 1, page 15,
and according to Standard Sheets 3 and 4, Table 2, page 17.
8. Dimensions and construction
Additionally to the requirements of Clause 8 in Part 1 the following criteria are to be
observed:
127-3 (2) © IEC — 1.1 —
8.2 Construction
The sub-miniature fuse-link shall be resistant to heat according to Sub-clause 9.7 of Part 1 and to
fire in accordance with I E C Publication 695.
Compliance is checked by inspection.
This st
andard is based on the assumption that the case of the sub-miniature fuse-link is made of
glass, ceramic or similar non-combustible material. For other material, such as the optional insu-
lating sleeve or epoxy coating or similar material shown on Standard Sheet 2, additional tests are
under consideration.
8.3 Sub-miniature fuse-link terminations
The sub-miniature fuse-link terminations should be firmly attached so that it is not possible to
remove them without damaging the sub-miniature fuse-link.
The samples are pre-conditioned by immersion in water for 24 h at a temperature between 15 °C
and 35 °C.
Terminations shall withstand the mechanical forces likely to be encountered during normal use.
With the sub-miniature fuse-link held in a fixed position, each terminal in turn is subjected at
ambient temperature to the forces laid down in this standard. These forces shall be exerted in the
direction of the axis of the terminal and applied progressively without jerks. Test sample groups
shall be equally divided among the specific termination tests stipulated in the relevant Standard
Sheets.
Present test methods are to be performed in accordance with I EC Publication 68-2-21.
— For the tensile test (Ua l
), the force applied shall be 10 N.
—
For the thrust test (Ua 2), the force applied shall be 2 N.
—
For the bending test (Ub), if applicable, the force applied shall be 5 N and the number of bends
shall be one.
At the conclusion of testing, the sub-miniature fuse-link terminations shall remain firmly
attached and the voltage drop shall not exceed the maximum allowed in the relevant Standard
Sheet.
8.4 Termination configuration
The sub-miniature fuse-link terminations shall be designed to permit easy installation on printed
circuit wiring boards having a grid system of holes located on 2.54 mm centres, or into fuse-bases
having a spacing between the terminations which is compatible with the 2.54 mm grid system.
Note. —
Electrical and electronic circuit designers are advised to note that grid systems for holes located on 2.54 mm centres
may result in spacings between conductive tracks, in some applications, which do not provide sufficient creepage or
clearance for open-circuit conditions. In such circumstances, it may be necessary to modify the land area around the
mounting hole to ensure an acceptable minimum distance between conductive tracks or select a sub-miniature
fuse-link with longer terminations which can be formed to fit into hole spacings offering the necessary degree of
protection.
More details are given in the User Guide (under consideration as Pa rt 10).
9. Electrical requirements
Additionally to the requirements of Clause 9 in Pa rt 1 the following criteria are to be
observed:
9.1 Voltage drop
The use of a high impedance voltmeter is recommended for measuring the voltage drop. Voltage
drop shall be measured at the points marked with U in Figure 1, page 18.
127-3 (2) © I EC — 13 —
Breaking capacity
9.3
9.3.1 Additionally to the requirements of Sub-clause 9.3.1 in Pa rt 1 the following is to be observed:
Typical test circuits for a.c. and d.c. are given in Figure 3, page 20.
When alternating current is stipulated by the relevant Standard Sheets, the circuit power factor
shall be larger than 0.95. To obtain this result, the circuit current shall be adjusted by the use of
resistors with negligible inductance.
9.3.2 In addition to the criteria of failure prescribed in Part 1, in each of the tests, the sub-miniature
fuse-link shall operate satisfactorily without any of the following phenomena:
—
fusing together of the contacts or terminations;
—
illegibility of marking after test;
— piercing of the external surfaces visible to the naked eye.
The following phenomena are neglected:
— black spots on the sub-miniature fuse-link terminations;
— small deformations of the sub-miniature fuse-link terminations;
— cracking of the subminiature fuse-link.
Endurance tests
9.4
9.4.1 Endurance test at normal ambient temperature
Compliance is checked by subjecting the sub-miniature fuse-links to test method A or B as
required in the relevant Standard Sheets.
9.4.2 Test method A
As specified in Part 1, Sub-clause 9.4 a) to d).
9.4.3 Test method B
a) A direct current, specified in the relevant Standard Sheet, is passed through the sub-miniature
fuse-link for a period of 100 h. The current stability during the test shall be maintained within
± 1% of the adjustable value.
b) Finally, the voltage drop across the fuse-link is measured again according to Sub-clause 9.1. The
voltage drop across the fuse-link after the test shall not have increased by more than 10% of th e
value measured before the test. - -
c) After the tests, the marking shall still be legible and soldered joints on end caps etc. shall not
show any appreciable deterioration.
(under consideration)
9.8 Additional tests
Additional tests under consideration including environmental, physical and electrical character-
istics are as follows:
a) Flammability.
b) Solderability (I EC Publication 68-2-20).
c) Resistance to soldering heat.
d) Resistance to solvents.
Dielectric withstand voltage.
e)
Environmental test.
TABLE 1
Testing schedule, Standard Sheets 1 and 2
Sub-miniature fuse-link number
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64
Sub-
Description
clause
2 5 8 11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 6
...
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