ISO 6469-3:2011 pdf download – Electrically propelled road vehicles —Safety specifications — Part 3: Protection of persons against electric shock
ISO 6469-3:2011 pdf download – Electrically propelled road vehicles —Safety specifications — Part 3: Protection of persons against electric shock.
7.3 Protection under single-failure conditions
7.3.1 Potential equalization
As a general rule, exposed conductive parts o1 voltage class B electric equipment, including exposed conductive barriers/enclosures, shall be bonded to the electric chassis for potential equalization In accordance with the requiernents in 7.9.
7.3.2 Isolation resistance
The voltage class B electric circuits intended to be not conductively connected to the grid shall have 5ufficient isolation resistance in accordance with the requirements in 7.7.
lithe minimum Isolation resistance requIrement of such circuits cannot be maintained under all operational conditions and over the entire service life, one of the following measures shall be applied:
— monitoring of the isolation resistance periodically or continuously; an appropriate warning shall be provided if loss of isolation resistance is detected; the voltage dass B system may be deactivated depending on the operational state of the vehicle or the ability to activate the voltage class B system may be limited;
double or reinforced insulation instead of basic insulation:
one or more layers of insulation, barners andioi enclosures in addition to the basic protection:
— rigid barriers/enclosures with sufficient mechanical robustness and durability, over the vehicle service life.
Requirements on isolation resistance for voltage class B electric circuits intended to be conductively connected to the grid are given in 7.10,2.
NOTE 1 IsolatIon resistances below the required mirwmom values can occur due to delenoi’atlon 04 fuel cal (FC) systems’ cooltng liquids or of oertaln battery types
NOTE 2 Coordination between multiple isolation monitoring systems can be necessary, e.g. ckiring charging.
NOTE 3 Th. isolation resistence Is approximately zero (or a voltage class B electric CIxI conductively coenected to the grid.
NOTE 4 Addisonal layer(s) of insulation and double or reàiforced insulation include, but ere not limited to, those foc voltage class B wring.
NOTE 5 11w ngld barners.Ienclosuros Include, but are not limited to, power control enclosures, motor housings, connector casings and housings, etc They can be used as single measure instead 01 basic batnersienclosures to meet both basic and slne4ailure protection reqements.
7.3.3 Capacitive couplings
126.96.36.199 CapacitIve couplings between a voltage class B potential and electric chassis usually result from V capacitors, used for electromagnetic compatibdity (EMC) reasons, or parasitic capacitive couplings.
188.8.131.52 For d.c. body currents caused by discharge of such capacitive couplings when touching d.c. class B voltage, one of the following options shall be fulfilled:
energy of the total capacitance between any energized voltage class B live part and the electric chassis shall be 0,2 J at its maximum working voltage; total capacitance should be calculated based on designed values of related parts and components;
alternative mechanical or electrical measures for d.c. voltage dass B electric circuits: see 184.108.40.206.
220.127.116.11 For ac. body currents caused by such capacitive couplings when touchmg a.c. class B voltage one of the following options shall be fuihlled:
ac. body current shaM not exceed 5 mA when measured in accordance with IEC 60950-1; alternative mechanical or electrical measures for ac. voltage class B electric circuits; see 18.104.22.168.
22.214.171.124 Alternative electrical or mechanical measures include the following:
— double or reinforced insulation instead of basic insulation:
— one or more layers of insulation, barriers and/or endosures in addition to the basic protection; rigid barners/enclosures with sufficient mechanical robustness and durability, over the vehicle service life.
The voltage class B electric circuit in question may be de-energized as a protection measure. The monitoring of faults within the circuit or the detection of events may be used to trigger the de-energization. One of the following conditions shall be met for the de-energezed circuit.
The voltage shall be reduced to less than 30 V ac. (rrns) for a.c. circuits and 60 V d.c. for d.c. circuits. The total stored energy of the circuit shall be <0,2 J. The transition time to reach the de-energized state shall be specified by the manufacturer in accordance with expected failures and operating conditions 7.4 Alternative approach for protection against electric shock As an alternative to 7.3, the vehide manufacturer shall conduct an appropriate hazard analysis and establish a set of measures which give sufficient protection against electric shock under single-failure conditions. 7.5 Requirements for insulation If protection is provided by insulation, the live parts of the electric system shall be totally encapsulated by Insulation that can be removed only by destruction. The insulating material shall be suitable to the maximum working voltage and temperature ratings of the vehicle and its systems (see also Clause 4). The insulation 5hall have sufficient capability to withstand the usual voltage Compliance shall be tested in accordance with 8.3.