IEC 61991:2000 pdf free download – Railway applications -Rolling stock – Protective provisions againstelectrical hazards
1Scope
IEC 61991 offers a set of rules that are applied in the design and manufacture of electricalinstallations and equipment to be used on rolling stock so as to protect the persons fromelectric shocks.
The methods used to satisfy the rules may differ，in accordance with the procedures andpractices of the operating organization.
IEC 61991 is applicable to vehicles of rail transport systems, road vehicles powered by anexternal supply (trolley buses)，magnetic levitated vehicles and to the electrical equipmentinstalled in these vehicles.
This standard does not apply to
– mine railways in underground mines;
– crane installations, moving platforms and similar transport systems on rails;-funicular railways;
– temporary constructions.
Testing of vehicles against the requirements of lEC 61991 is not included.For this,referto IEC 61133.
2Normative references
The following normative documents contain provisions which，through reference in this text,constitute provisions of lEC 61991.For dated references,subsequent amendments to，orrevisions of,any of these publications do not apply.However, parties to agreements based onIEC 61991 are encouraged to investigate the possibility of applying the most recent editions ofthe normative documents indicated below. For undated references,the latest edition of thenormative document referred to applies. Members of lEC and lS0 maintain registers ofcurrently valid lnternational Standards.
IEC 60077-1,— Railway applications – Electric equipment for rolling stock – Part 1:Generalservice conditions and general rules 1)
IEC 60364 (all parts)，Electrical installations of buildings
IEC 60364-4-41:1992，Electrical installations of buildings – Part 4: Protection for safety -Chapter 41 : Protection against electric shock
IEC 60439 (all parts),Low-voltage switchgear and controlgear assemblies
IEC 60479-1:1994,Effects of current on human beings and livestock – Part 1 : General aspectsIEC 60529:1989，Degrees of protection provided by enclosures (IP Code)
4.2connections between circuits
Circuits operating at different nominal voltages connected by power conversion equipmentwhich does not provide a conducting path between them, or circuits which are linked only by aconnection direct to the vehicle body external to the power conversion circuitry，shall beindividually classified at the nominal voltage of each circuit.
lf the conducting paths referred to in this subclause include capacitive or inductiveconnections，whose impedance is low enough to induce hazardous voltages into any circuitunder either normal or fault conditions, then all the circuits so connected shall be classified atthe nominal voltage of the highest voltage circuit.
NOTE This condition can apply to circuits connected，for example，by means of a chopper converter withimpedance coupling.
Where circuits are linked conductively to a higher voltage source other than simply by circuitbonds connected to the vehicle body (for example by an auto-transformer or potential divider),all circuits in the group shall be treated as if energized at the nominal voltage of the source,unless the conditions of 4.3 have been met.
4.3Exceptions
lf voltage conversion from one band to another involves overvoltage detection resulting indisconnection of the primary or the secondary circuit，or having other means capable ofpreventing excessive voltage in the secondary circuit，then the secondary circuit shall beclassified according to the highest voltage at which the detection equipment will operate.
NOTE The integrity of the detection equipment should be taken into account.
Circuits not connected to the vehicle body, for example floating supplies, shall be classified asappropriate in order to ensure that the requirements of this standard are met,taking dueaccount of the potentials possible in such circuits under normal or fault conditions.
5 Protective provisions against direct contact
Live parts capable of causing an electric shock shall be protected against direct contact.Alltypes of equipment shall be capable of being operated without loss of protection against directcontact. Protection against direct contact shall be provided by at least one of the meansdescribed in 5.1 to 5.3,supplemented as necessary by warning labels as described in 5.4.
5.1 Protection by insulation
In addition to the requirements of lEC 60077-1, the insulating materials used to cover live partsshall be appropriate to the nominal equipment operating voltage and the conditions of use.Further provisions should be considered in order to minimize the consequences of damage.