SIST EN 60215:2001
(Main)Safety requirements for radio transmitting equipment
Safety requirements for radio transmitting equipment
Applies to radio transmitting equipment operating under the responsibility of skilled personnel and deals with protection against electric shock, skin burns, high temperature and fire, implosion and explosion, harmful radiation and miscellaneous hazards. Includes design and construction requirements and test methods to ensure -safety of personnel, when the equipment is operating under conditions of normal use and certain fault conditions, when carrying out adjustments, during fault finding, and repair of the equipment; -prevention of fire and its spread.
Sicherheitsbestimmung für Funksender
Règles de sécurité applicables aux matériels d'émission radioélectrique
S'applique aux matériels d'émission radioélectrique exploités sous la responsabilité d'un personnel qualifié et traite de la protection contre les chocs électriques, les brûlures, les températures élevées, le feu, les implosions et explosions, les rayonnements dangereux et les dangers divers. Comprend les règles de conception et de construction et des méthodes de mesure afin d'assurer: - la sécurité du personnel, lorsque le matériel fonctionne dans les conditions normales d'emploi, ainsi que certaines conditions de dérangement, lors des réglages, de la recherche de défauts et de réparation du matériel; - la prévention du feu et de sa propagation. Comprend les principaux chapitres de CEI 284
Safety requirements for radio transmitting equipment (IEC 60215:1987)
General Information
Relations
Standards Content (Sample)
SLOVENSKI SIST EN 60215:2001
prva izdaja
STANDARD
december 2001
Safety requirements for radio transmitting equipment (IEC 60215:1987)
ICS 33.060.20 Referenčna številka
SIST EN 60215:2001(en)
© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno
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INTERNATIONAL IEC
STANDARD 60215
Third edition
1987
Safety requirements for radio transmitting
equipment
IEC 1987 Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical,
including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
PRICE CODE
T
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
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215©IEC1987
CONTENTS
Page
FOREWORD 7
PREFACE 7
INTRODUCTION 9
Clause
1. Scope 9
2. Object 9
SECTION ONE — TERMINOLOGY
11
3. Definitions
SECTION Two — CONDITIONS OF NORMAL USE AND FAULT CONDITIONS
4. Introduction 13
15
5. Conditions of normal use
15
6. Fault conditions
SECTION THREE — COMPONENTS AND CONSTRUCTION
17
7. Introduction
Components 17
8.
19
9. Construction
10. Markings relevant to safety 21
SECTION FOUR — PROTECTION AGAINST HARMFUL ELECTRICAL SHOCK
AND RADIO-FREQUENCY SKIN BURNS
21
11. Introduction
Earthing 23
12.
Enclosures 23
13.
27
14. Mechanical considerations concerning safety devices
27
15. Wiring
27
16. Insulation
29
17. Voltages at the radio-frequency output connection
SECTION FIVE — HIGH TEMPERATURES, FIRE AND MISCELLANEOUS HAZARDS
Introduction 29
18.
29
19. High temperatures
31
20. Fire
31
21. Implosion and explosion
31
22. Harmful radiation
33
Dangerous materials 23.
33
24. Dangerous short-circuiting of low voltage supplies
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215©IEC1987
APPENDIX A — References to other publications 35
APPENDIX B — Clearances and creepage distances 37
APPENDIX C - Symbols 39
APPENDIX D — Guidance on assessing the competence of personnel for designation as skilled 43
APPENDIX
E — Guidance on safety precautions to be observed by personnel working on radio
transmitting equipment 45
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215©IEC1987 — 7
INTERNATIONAL ELECTROTECHNICAL COMMISSION
SAFETY REQUIREMENTS
FOR RADIO TRANSMITTING EQUIPMENT
FOREWORD
The formal decisions or agreements of the I EC on technical matters, prepared by Technical Committees on which all the National
1)
rnational consensus of opinion
Committees having a special interest therein are represented, express, as nearly as possible, an inte
on the subjects dealt with.
They have the form of recommendations for inte rnational use and they are accepted by the National Committees in that
2)
sense.
ational unification, the I EC expresses the wish that all National Committees should adopt the text of
3) In order to promote inte rn
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 12C: Transmitting Equipment, of I EC Technical
Committee No. 12: Radiocommunications.
This third edition replaces the second edition of I EC Publication 215 (1978).
The text of this standard is based upon the following documents:
Six Months' Rule Report on Voting
12C(CO)186 12C(CO)195
Full information on the voting for the approval of this standard can be found in the Voting Report
indicated in the above table.
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215©IEC 1987
SAFETY REQUIREMENTS
FOR RADIO TRANSMITTING EQUIPMENT
INTRODUCTION
This third edition of safety requirements for radio transmitting equipment supersedes, and replaces in a
215 (1978) and 284 (1968).
single volume, two earlier IEC Publications:
The requirements and test methods in this standard are similar to those given in the second edition of
I E C Publication 215 and continue to apply only to radio transmitting equipment operating under the
responsibility of skilled personnel as defined in Sub-clause 3.1. The text of Appendix E is based on the
284, which has now been withdrawn.
contents of I EC Publication
ational bodies referred to in this standard
The titles of I EC publications and publications of other inte rn
are given in Appendix A.
1. Scope
This standard applies to radio transmitting equipment, including any auxiliary apparatus neces-
sary for its normal operation as defined in I EC Publication 244-1, operating under the responsi-
bility of skilled personnel. It applies to all radio transmitting equipment and ancillary apparatus,
associated feeder
including combining units and matching networks. Only the antenna system and
lines are excluded.
This standard does not apply to transmitters of safety-insulated construction using double insu-
lation or reinforced insulation and without provision for protective earthing.
This type of equipment is designated "Class II Equipment" in I EC Publication 536 and is usually
marked with the symbol shown in Sub-clause C2.2 of Appendix C.
2. Object
This standard deals with protection against:
— electric shock;
— skin burns;
— high temperature and fire;
—
implosion and explosion;
— harmful radiation;
—
miscellaneous hazards.
Design and construction requirements and, where appropriate, test methods are specified
covering:
a) the safety of skilled personnel when operating, carrying out routine adjustments to, and as far as
practicable, during fault finding and repairing the equipment;
b) the safety of personnel, including unskilled personnel directed by skilled personnel, when the
equipment is operating normally, and also when operating under certain specific fault conditions
which may arise in normal use;
c)
the prevention of fire and its spread.
These requirements do not necessarily ensure the safety of unskilled personnel working on the
equipment when it is not in normal operation.
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215©IEC1987
Tests are specified, where appropriate, for checking that the equipment meets the safety require-
ments of this standard when operating normally and also under the specified fault conditions. The
tests should be carried out on a representative set of equipment in order to determine whether the
design meets the requirements of this standard. The tests are neither mandatory nor limiting and
may be modified by agreement between manufacturer and purchaser.
The use of this standard is not, however, intended to be restricted to type tests. It may also be used
for acceptance tests after installation of the equipment, for tests after modifications to pa rts of the
equipment, and for tests at appropriate intervals to ensure the continuing safety of the equipment
throughout its life.
SECTION ONE — TERMINOLOGY
3. Definitions
The following definitions apply for the purpose of this standard.
Skilled personnel
3.1
Personnel are considered to be skilled if they have the necessary knowledge and practical
rise
ng to appreciate the various hazards that can a
experience of electrical and radio enginee ri
from working on radio transmitters, and to take appropriate precautions to ensure the safety of
personnel.
Guidance on assessing the competence of personnel for designation as skilled is given in Appen-
dix D.
The above definition and the guidance in Appendix D detail the minimum requirements for a skilled person. In
Note. —
countries more stringent requirements for qualifications, training and experience are stipulated, with formal
some
certification.
3.2 Electrically safe
is electrically safe if it cannot cause a harmful electric shock or radio-frequency skin-
A part
burn.
The conditions for a part to be electrically safe are:
either
and earth, and also between the pa rt and any other accessible part,
a) The voltage between the pa rt
does not exceed 72 V peak when measured with an instrument having an internal resistance of
not less than 101(51 per volt;
or
b) the voltage exceeds 72 V peak, but the following limits with regard to both current and capacity
apply:
Current limits
Frequency Current limit
d.c. 2 mA
< 0.7 mA (peak)
1 kHz
1 kHz to 100 kHz 0.7 f mA (peak)
70 mA (peak)
> 100 kHz
rt
Where the current is measured in a non-inductive resistor of 2142 connected between the pa
—
f rtz.
concerned and earth or any other accessible pa rt ; and where is the frequency in kilohe
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215 © IEC 1987 — 13 —
Capacitance limits
Voltage range
(U) Capacity limit
(Peak value)
(V) (of)
72 to 450 0.1
450 to 15 000 45/U
> 15 000 675 000/U
—
Where the indicated limit which is the capacity between the pa rt and earth, or any other
accessible part, and the peak voltage
(U) is measured in volts with an instrument having an
internal resistance of not less than 10 kS2 per volt.
Note. —
Further information on the effects of a current passing through the human body is given in Sub-clause E2, of
Appendix E.
3.3 Creepage distance in air
Denotes the shortest distance, measured in air over the surface of the insulation, between two
conductive parts.
3.4 Clearance in air
Denotes the shortest distance, measured in air, between two conductive pa
rts.
3.5 By hand
Denotes that the operation does not require the use of a tool, coin or any other object.
3.6 Accessible part
A part
is accessible if it can be touched by either of the standard test fingers described in I E C
Publication 529, when applied in any direction with a force not exceeding 50 N.
In addition, to guard against flashover, any pa rt
carrying a voltage is regarded as accessible if its
distance to the test finger is less than the clearances given in Appendix B.
3.7 Enclosure
Denotes a space in which items of equipment that might be dangerous are located and access to
which is prevented except by routes specially provided, for example, a door or a removable cover
plate.
3.8 Safety device
Denotes any pa rt
or component provided for the purpose of protecting personnel from possible
injury.
SECTION TWO — CONDITIONS OF NORMAL USE
AND FAULT CONDITIONS
4. Introduction
This section sets out the range of conditions of normal use and the fault conditions under which
the equipment may operate without danger to personnel, including unskilled personnel directed by
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215©IEC1987
skilled personnel. The equipment shall meet the safety requirements of this standard when oper-
ating under the conditions of normal use given in Clause 5 and also when any of the initial fault
conditions detailed in Clause 6 have been applied.
5. Conditions of normal use
The ambient atmospheric conditions for the equipment are within the following range:
a)
— temperature: +5 °C to +45 °C;
relative humidity: 45% to 75%;
— air pressure: 86 kPa to 106 kPa (kN/m2),
(860 mbar to 1 060 mbar);
or within more stringent conditions agreed between manufacturer and purchaser.
b)
The supply voltage and frequency are within the range for which the equipment has been
designed.
c) For a.c. equipment, the waveform of the supply voltage is substantially sinusoidal. (See Clause 5
of I EC Publication 244-1 for the definition of "substantially sinusoidal").
d) For equipment which may be operated from a.c. or d.c., either supply is applied separately.
e) The safety earth terminals or contacts, if any, are connected to earth (see Sub-clause 12.1). Any
other earth terminals shall also be connected to earth, unless the terminals are designed to be
tightened by hand; in which case, they are left unconnected.
f) The access doors and cover plates or other protective covers, if any, are closed or fixed in
position, unless they are designed to be opened or removed by hand; in which case they are left
open or removed.
g) The equipment is operating in any position for which it has been designed to be used.
h) The equipment has its accessible controls at any setting.
The equipment is operating with any input signal condition given in the equipment specifica-
i)
tion.
6. Fault conditions
Operating under fault conditions denotes that, with the equipment operating under the condi-
tions of normal use given in Clause 5, one of the faults a) to h) listed below, is present together with
any associated consequential faults arising. The initial faults shall be applied separately, in tu rn, in
any convenient order.
circuits across creepage distances, if they are less than the values given in Appendix B,
a) Short
unless the insulation complies with the provision of Clause 16.
Sho circuits across clearances in air, if they are less than the values given in Appendix B.
b) rt
c) A potentially dangerous failure of any component as determined from inspecting the equipment
and studying the circuit diagram, unless the component is known to comply with an I EC test
recommendation appropriate to the conditions of use in the equipment.
d) Connection of any unfavourable impedance to the radio-frequency output connection, including
open circuits and short circuits.
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215©IEC1987 — 17 —
e) Failure of any cooling system.
f)
Continuous operation of motors, intended for intermittent operation, unless protection against
this is included in the equipment.
g) Locking of moving parts in rotating or linear operating devices, if these pa rts can be jammed by
mechanical failure.
h) The loss of a phase on a three-phase supply.
SECTION THREE — COMPONENTS AND CONSTRUCTION
oduction
7. Intr
The purpose of this section is to ensure that the equipment is designed and constructed to ensure
safety of personnel throughout the life of the equipment.
Where no test method is given, compliance shall be checked by visual inspection and where
appropriate by a functional test.
Components
8.
8.1 General requirements
Components shall not be loaded in excess of their ratings under normal conditions nor, as far as
practicable, under fault conditions. Normal and fault conditions are detailed in Clauses 5 and 6.
Components which are known to comply with an I EC test recommendation appropriate to the
conditions of use in the equipment need not be tested.
When this is not so, the components may be tested either in the equipment or externally under
conditions equivalent to those applying in the transmitter. The number of components to be tested
shall be agreed between manufacturer and purchaser.
8.2 Connectors
a) Connectors shall be designed so that they cannot be mated in a manner which might cause a
hazard, for example, a connector for a circuit other than a supply circuit shall not be able to
accept a mains supply connector. Mains supply connectors shall not be used for any other
purpose, for example, for low-voltage supplies or signal circuits.
Connectors shall be constructed so as to prevent a bare wire inserted into the connector from
b)
penetrating the connector and making contact with any other pa rt .
c) Connectors and internal connections for ancillar y purposes such as monitoring shall have
clearance and creepage distances in air to other circuits at least twice those specified in
Appendix B.
Connectors with a non-detachable cord or cable shall comply with the requirements of I EC
d)
Publication 65.
8.3 Switches
Circuit-breakers and manually-operated switches for the mains supply and other supply circuits
shall have adequate making and breaking capacity under conditions of normal use. Circuit-breakers
shall also have adequate making and breaking capacity under fault conditions.
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215©IEC1987
Switches, including circuit-breakers and safety isolators, shall disconnect the equipment simul-
taneously from all poles of the supply source necessary to make the equipment safe.
An indication of the "on" and "off' position of such switches shall be provided and be clearly
visible.
In some countries local regulations require that the neutral pole be isolated to render the equipment safe and in
Note. —
others that this should not be done.
8.4 Fuse-links
Fuse-links shall have an enclosed fuse-element. The rating of the fuse-link shall be marked on the
fixed part of the assembly or adjacent to it.
8.5 Parts subject to corrosion
The equipment shall be constructed so that there is no danger to personnel resulting from the
failure of any part due to corrosion.
Tests shall be agreed between manufacturer and purchaser and shall be performed after the
equipment has been subjected to the appropriate corrosion test given in I EC Publication 68-2.
8.6 Solid state switches and contactors
Under consideration.
8.7 Photocouplers
Under consideration.
Fibre optics
8.8
Under consideration.
9. Construction
9.1 General requirements
The equipment shall, as far as practicable, be constructed of non-flammable materials and shall
a)
have adequate strength to ensure safety.
b) Where the slackness of electrical connections could constitute a hazard, their tightness shall not
be dependent upon the degree of compression applied to an insulating material.
Screws which serve both as electrical and mechanical connections shall be adequately locked.
c) Moving parts liable to cause personal injury shall be adequately guarded.
s can be set in motion by remote control suitable precautions shall be incorporated to
d) Where part
prevent possible injury.
e) Equipment shall be mechanically designed to minimize the possibility of injury to personnel, for
example, from sharp edges, protruding corners, hot pipes, the release of potential energy from,
ng, etc. Warnings shall be displayed where appropriate.
for example, a spri
f) Attention shall be paid in the design of equipment to minimize the generation of acoustic noise,
as exposure to excessive noise can cause damage to hearing and to the nervous system.
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215©IEC1987 — 21 —
Where noise exceeds the safe value recommended in ISO Standard 1999, notices shall be
displayed giving the safe exposure time allowed and recommending that ear protectors should
be worn. Such noise levels may, for example, exist in rooms housing cooling plant for large
transmitters.
Resistance to humidity
9.2
Tests to check resistance to humidity shall be agreed between manufacturer and purchaser and
shall be made after the equipment has been subjected to the appropriate damp heat test given in
I EC Publication 68-2.
9.3 Resistance to ingress of water
If the transmitter is specified as protected against the ingress of water (see symbols in Sub-clause
C3.1 to C3.4 of Appendix C), it shall remain safe when tested under the conditions agreed between
manufacturer and purchaser. The tests shall be made after the equipment has been subjected to the
appropriate sealing test given in I EC Publication 68-2.
9.4 Housing of batteries
The arrangements for housing batte ries shall provide adequate ventilation to remove noxious gas
and vapours and ensure that leakage of electrolyte will neither cause damage to other pa rts nor
endanger personnel.
10. Markings relevant to safety
a) Markings shall be indelible and remain easily legible and discernible throughout the life of the
equipment. Compliance is checked by visual inspection and by the following tests:
1) It shall not be possible to remove the marking by rubbing lightly in turn with two pieces of
cloth, one soaked with water, the other with petroleum spi rit.
2) When exposed to sunlight, the marking shall not fade so as to become illegible.
The conditions of this test are under consideration.
b) Markings shall, as far as practicable, be in the language appropriate to the area in which the
equipment is to be used. The use of symbols, in accordance with Appendix C, is recommended
to avoid language problems.
c) Switches and isolators specifically provided to render equipment safe shall be clearly marked as
such to prevent ambiguity between these switches and other switches. The marking shall be in
accordance with Item b) above.
d) Parts which serve as protection against harmful radiation, and which are intended to be removed
during servicing, shall be marked with an appropriate warning.
SECTION FOUR — PROTECTION AGAINST HARMFUL ELECTRICAL SHOCK
AND RADIO-FREQUENCY SKIN BURNS
11. Introduction
This section sets out the design principles that must be followed for transmitters in which dan-
gerous voltages are present.
Where no test method is given, compliance shall be checked by visual inspection and, where
appropriate, by a functional test.
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215©IEC1987 23 —
12. Earthing
12.1 Safety earth terminal
s shall be reliably connected to a safety earth.
Accessible conductive part
In addition, the following provisions shall apply:
a) Equipment to be connected to fixed wiring
A separate safety earth terminal shall be used. The terminal shall preferably be adjacent to the
mains terminals, and shall be marked with the symbol in Sub-clause C2.1 of Appendix C.
The material of the earth terminal shall be electrolytically compatible with a copper earth
conductor.
It shall not be possible to loosen the earth connection by hand.
b) Equipment provided with a non-detachable flexible cord or cable
The requirements of Item a) above shall apply.
In addition, the cord or cable used for connecting the equipment to the mains supply shall
include an insulated earth conductor of adequate cross-section, colour-coded in accordance with
IEC Publication 173. This conductor shall be connected to the safety earth terminal of the
equipment and, if a plug is provided, to the safety earth contact of the plug.
c) Equipment provided with a mains supply connector
The mains supply connector shall incorporate a safety earth contact which shall be an integral
part of the connector.
The safety earth shall make contact before the supply when inserting the connector; it shall break
after the supply is broken when removing the connector.
Safety earth terminals and safety earth contacts shall not be used for any other purpose.
12.2 Safety earth connections
a) Reliance shall not be placed on the conductibility of the cabinet or framework for safety earth
connections. Separate conductors routed to provide a suitably low impedance shall be used so
that accessible pa rts are electrically safe both under normal conditions of use and under fault
conditions.
b) Safety earth conductors shall not be used for any other purpose.
13. Enclosures
The requirements for safety devices preventing access to enclosures whilst dangerous voltages are
present are given in Sub-clause 13.1 below. (See Sub-clauses 3.7 and 3.8 for definitions of enclosure
and safety device.)
Permissible voltages remaining on the equipment after the enclosures have been opened are given
in Sub-clause 13.2. Some additional safety provisions are described in Sub-clause 13.3.
13.1
Safety devices relating to enclosures
a)
It shall not be possible to open access doors, or to remove cover plates or other protective covers
which are designed to be removed by hand, before all dangerous voltages have been removed
and accessible pa
rts have been made electrically safe.
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215 © IEC 1987
s subject to peak voltages in excess of 1 000 V with
In addition, it is recommended that all pa rt
respect to earth shall be earthed by means of a safety earthing switch before such opening or
removal is possible.
b) The protection shall be accomplished by safety devices forming pa rt of the equipment. The
design of the safety system shall be such that the safety of personnel is not dependant solely upon
the satisfactory operation of relays, contactors, circuit breakers, etc. which are electrically oper-
ated or employ hydraulic or pneumatic arrangements. For additional mechanical considerations
concerning safety devices, refer to Clause 14.
c) The coupling between the safety mechanism and the locking of the means of access shall be
effected in such a way that it will not be possible to gain access to an enclosure without the safety
devices having operated correctly. To achieve this, a mechanical system is normally neces-
sary.
The reapplication of dangerous voltages shall not be possible until the earth connection estab-
d)
lished by the safety earthing switch, if any, has been disconnected, and any cover plates have
been replaced and access doors closed.
The safety system for equipment with access doors for enclosures shall include an arrangement
e)
to enable any person entering the enclosure to prevent the doors being closed and dangerous
voltages being reapplied while he is inside.
13.2 Voltages remaining on the equipment
a) Parts becoming accessible after access doors have been opened, or cover plates or other protec-
tive covers designed to be removed by hand have been removed, shall be electrically safe in
accordance with Sub-clause 3.2.
a) of Sub-clause 3.2, it is permitted to
b) In addition to the voltages which are allowed under Item
have voltages on the equipment which do not comply with the requirements of Item b) of the
same sub-clause, provided that these voltages are not accessible and are less than 354 V peak
with respect to earth, as measured with an instrument having an internal resistance of not less
that 10 kI2 per volt.
Access shall be prevented by means of separate protective covers which cannot be removed
ry an appropriate warning in accordance with Item b) of
by hand. These covers shall car
Clause 10.
13.3
Additional provisions
a) As far as feasible, earthing wands shall be provided as an additional safety measure.
Such wands shall consist of an insulated handle, appropriate for the voltage encountered in the
equipment, with a rigid conducting hook at one end. A flexible conductor of adequate cross-
sectional area shall connect the conducting hook visibly to earth. If insulation is used on the
conductor, it shall be transparent and loosely fitting over the conductor. Insulating beads may be
used instead.
b) The design of the equipment shall be such that it is impossible to receive an electric shock by
touching insulating material surfaces on the exterior, such as windows for viewing instruments,
decorative features, etc., which are not earthed.
Compliance is checked by a voltage test in accordance with Sub-clause 3.2.
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215©IEC1987
14. Mechanical considerations concerning safety devices
Safety devices shall be designed in accordance with the "fail-safe" principle. They shall remain
a)
in or go to a condition which provides protection to personnel in the event of a fault within the
device.
There shall be no possibility of a false indication of safety.
b)
The operation of safety devices shall be such that transition from the "safe" position to the
c)
"unsafe" position cannot be carried out without deliberate action, nor shall there be ambiguity
between the "safe" position and the "unsafe" position.
It shall not be possible to disable a safety device by hand.
d)
Safety devices shall be designed to withstand such mishandling as may be expected in practice
e)
and continue to remain effective throughout the life of the equipment.
f) Safety earthing switches shall be so constructed and mounted that the closing of the contacts is
directly visible from a safe location.
Handles, knobs, etc., forming part of the safety system shall be reliably fixed to their shafts.
g)
Mechanical drives shall be such as to prevent the possibility of slip or incorrect registration. This
shall be ensured by positive means such as keys, fully-secured pins, etc.
All pa s of the safety system, including mechanical couplings, bearings, taper pins, etc., shall be
h) rt
reasonably accessible for inspection and maintenance.
15. Wiring
a) All conductors and cables shall be adequately protected against any risk of mechanical damage
to which they may be liable in normal conditions of service.
ring, keying, control or modu-
b) Conductors within the equipment which are intended for monito
lating purposes, and which are connected to external circuits shall be protected from possible
contact with the other conductors within the equipment by adequate insulation, and preferably
by physical separation, or by the use of an earthed screen.
c) The terminating arrangement for flexible cables shall ensure that the electrical connections are
free from mechanical strain and that the cables are protected from abrasion.
16. Insulation
a) Where creepage distances are smaller than those specified in Appendix B, the insulating material
shall be non-tracking and non-flammable.
For materials other than ceramic, the comparative tracking index shall be determined by the test
method given in I EC Publication 112.
The insulating material will be considered to be non-tracking if the comparative tracking index
is equal to or greater than 175.
Flammability shall be checked by the appropriate test given in I EC Publication 695.
b) Smaller creepage distances are allowed inside thermionic tubes, on tube bases and sockets,
relays, plugs and sockets, printed circuit boards, transistors, micro-modules and similar devices,
provided that they comply with their own specification.
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215©IEC1987 — 29 —
17. Vo
...
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