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Protection against electrical shock - Coggle Diagram

- - - - Measures to prevent the occurrence of a touch voltage
        
        Prevention of the occurrence of a touch voltage
        
        Measures to prevent the occurrence of a touch voltage include the following
        
        provision of class II equipment or by equivalent insulation
        
        This measure is intended to prevent the occurrence of touch voltages on the accessible parts
        through a fault in the basic insulation.
        
        This protection is provided by one or more of the following:
        
        class II electrical devices or apparatus
        
        3 more items...
        
        switchgear and controlgear assemblies having total insulation in accordance
        with IEC 61439-1
        
        supplementary or reinforced insulation in accordance with IEC 60364-4-41
        
        electrical separation
        
        For this type of protection, the requirements of IEC 60364-4-41 apply
        
        intended to prevent a touch voltage through
        contact with exposed conductive parts that can be energized by a fault in the basic insulation
        of the live parts of that circuit.
      - Automatic disconnection of the supply before the time of contact with a touch voltage can become hazardous
        
        Protection by automatic disconnection of supply
        
        Automatic disconnection of the supply of any circuit affected by an insulation fault is intended to prevent a hazardous situation resulting from a touch voltage.
        
        This measure consists of the interruption of one or more of the line conductors by the automatic operation of a protective device in case of a fault
        
        Shall:warning: occur within a sufficiently short time to limit the duration of a touch voltage to a time within the limits specified in Annex A for TN and TT systems
        
        This measure necessitates co-ordination between
        
        the type of supply system
        
        the supply source impedance
        
        the earthing system
        
        the impedance values of the different elements of the line
        
        of the associated fault current paths through the protective bonding circuit
        
        the characteristics of the protective devices that detect insulation fault(s)
        
        Details of verification of conditions for protection by automatic disconnection of supply are provided in 18.2.
        
        This protective measure comprises both
        
        protective bonding of exposed conductive parts (see 8.2.3)
        
        one of the following
        
        In TN systems, the following protective devices May be used
        
        overcurrent protective devices
        
        residual current protective devices (RCDs) and associated overcurrent protective device(s)
        
        The preventive maintenance can be enhanced by use of a residual current monitoring device,
        RCM, complying with IEC 62020
        
        where disconnection within the time specified in A.1.1 cannot be assured, supplementary protective bonding Shall:warning: be provided as necessary to meet the requirements of A.1.3. (see annex A)
        
        in TT systems either
        
        or RCDs and associated overcurrent protective device(s)
        
        1 more item...
        
        or overcurrent protective devices May be used for fault protection provided a suitably low value of the fault loop impedance Zs (see A.2.2.3) is permanently and reliably assured
        
        In IT systems
        
        the relevant requirements of IEC 60364-4-41 Shall:warning: be fulfilled
        
        During an insulation fault both of the following Shall:warning: be sustained
        
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        Where a power drive system (PDS) is provided
        
        fault protection Shall:warning:be provided for those circuits of the power drive system that are supplied by the converter
        
        Where this protection is not provided within the converter
        
        the necessary protection measures Shall:warning: be in accordance with the converter manufacturer’s instructions
  - - - the following Shall :warning: be located inside an enclosure
        
        live parts of at least IP2X or IPXXB (see IEC 60529). to protect against contact with them
      - the surfaces of the enclosure that are readily accessible Shall :warning: have the following minimum degree of protection against contact with live parts
        
        IP4X or IPXXD.
      - Opening an enclosure (i.e. opening doors, lids, covers, and the like) Shall :warning: be possible only under one of the following conditions
        
        The use of a key or tool is necessary for access. intended to restrict access to skilled or instructed persons (see 17.2 f)
        
        All live parts (inside and outside of the enclosure) that are likely to be touched because they hold buttons/DIP switches/ect... for ressetting or adjusting while the equipment is still connected Shall :warning: be protected against contact to at least IP2X or IPXXB
        
        other live parts inside Shall :warning: be protected against unintentional direct contact to at least IP1X or IPXXA
        
        The disconnection of live parts inside the enclosure before the enclosure can be opened.
        
        MAY be accoplished by interlocking the door with a disconnecting device (for example the supply disconnecting device)
        
        the door can only be opened when the disconnecting device is open
        
        the disconnecting device can only be closed when the door is closed
        
        exception: a key or tool as prescribed by the supplier can be used to defeat the interlock only if the following conditions are met
        
        it is still possible to do LOTO
        
        it is still possible to open the disconnecting device
        
        upon closing the door, the interlock is automatically restored
        
        All live parts (inside and outside of the enclosure) that are likely to be touched because they hold buttons/DIP switches/ect... for ressetting or adjusting while the equipment is still connected are protected against contact to at least IP2X or IPXXB
        
        other live parts inside are protected against unintentional direct contact to at least IP1X or IPXXA
        
        relevant information about the procedures for the defeat of the interlock is provided
        with the instructions for use of the electrical equipment (see Clause 17)
        
        means are provided to restrict access to live parts behind doors that are not directly interlocked with the disconnecting means to skilled or instructed persons. ( see 17.2 b)
        
        for example plastic cover
        
        parts that are still live after switching off the disconnecting device Shall :warning: have the following
        
        protections against direct contact to at least IP2X or IPXXB (see IEC 60529)
        
        marked with a warning sign in accordance with 16.2.1 (see also 13.2.4 for identification of conductors by colour)
        
        except for
        
        parts that can be live only because of connection to interlocking circuits and that are distinguished by colour as potentially live in accordance with 13.2.4
        
        the supply terminals of the supply disconnecting device when the latter is mounted alone in a separate enclosure.
        
        Opening without the use of a key or a tool and without disconnection of live parts Shall :warning: be only possible when
        
        all live parts are protected against contact to at least IP2X or IPXXB (see IEC 60529).
        
        Where barriers provide this protection
        
        or they Shall :warning: require a tool for their removal
        
        or all live parts protected by them Shall :warning: be automatically disconnected when the barrier is removed
        
        if a hazard can be caused by manual actuation of devices (for example manual closing of contactors or relays)
        
        such actuation should be prevented by barriers or
        obstacles that require a tool for their removal.
    - - Live parts protected by insulation shall be completely covered with insulation that can only be removed by destruction.
        
        the insulation Shall :warning:be capable of withstanding the mechanical, chemical, electrical, and thermal stresses at nominal operation
      - Paints, varnishes, lacquers, and similar products alone are generally considered to be inadequate for protection against electric shock under normal operating conditions.
    - - or with a minimum degree of protection against contact with live parts
        corresponding to IP4X or IPXXD (see IEC 60529)
      - or
    - - Live parts having a residual voltage greater than 60 V when the supply is disconnected Shall :warning: be discharged to 60 V or less within a time period of 5 s provided that this rate of discharge does not interfere with the proper functioning of the equipment.
        
        Exemption: components having a stored charge of 60 µC or less.
        
        Where this specified rate of discharge would interfere with the proper functioning of the equipment
        
        a durable warning notice drawing attention to the hazard and stating the delay required before the enclosure may be opened Shall :warning: be displayed at an easily visible location on or immediately adjacent to the enclosure that contains the live parts.
        
        for example Frequency converters and DC bus supplies
      - In the case of plugs or similar devices
        
        or the withdrawal of which results in the exposure of conductors (for example pins), the discharge time to 60 V Shall :warning: not exceed 1 s
        
        or such conductors Shall :warning: be protected to at least IP2X or IPXXB
        
        If neither can be achieved
        
        for example in the case of removable collectors on conductor wires, conductor bars, or slip-ring assemblies, see 12.7.4
        
        or additional switching devices Shall :warning:be provided
        
        or an appropriate warning Shall :warning: be provided
        
        for example a warning sign drawing attention to the hazard and stating the delay required
        
        :warning:NOT SUFFICIENT:warning: when the equipment is located in places open to all persons, which can include children
        
        a minimum degree of protection against contact with live parts to IP4X or IPXXD is required
    - - the requirements of IEC 60364-4-41 Shall :warning: apply
    - - For conductor wire systems or conductor bar systems with a degree of protection less than
        IP2X or IPXXB, see 12.7.1.