ISO 6469-3 pdf download – Electrically propelled road vehicles —Safety specifications — Part 3: Protection of persons against electric shock

ISO 6469-3 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 01 voltage class B electric equipment including exposed conductive barriers/enclosures, shall be bonded to the electric chassis for potential equalization in accordance with the requirements 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 sufficient
isolation resistance in accordance with the requirements in 7.7.
If the 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 shell 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 class 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, bamers and/or enclosures in addition to the basic protection; flgid 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 7.102.
NOTE 1 Isolation resistances below the requeed minimum values can occur due to detedoratlon of fuel cell (FC) systems’ cooling liquina or of cettain battery types.
NOTE 2 Coordination between multiple isolation monitoring systems can be necessary. e 9. during charging.
NOTE 3 The isolation resistance is approximately zero for a voltage class B eledflc circuit conckactively corw’iected to bfl
NOTE 4 Addeonel layer(s) of insulation and doudle or reinforced insulation Include, but are not lI,mted to. those for voltage class B wring.
NOTE S The ngid bemers)enciosaxes include, but are not limited to, power control enclosures, motor housings, connector casings and housings. etc They can be used as single measure instead of basic barriersienclosises to meet both basic and slne-fadure protection requirements.
7.3.3 CapacItive couplIngs
7.3.3.1 CapacItive couplings between a voltage class B potential and electric chassis usualy result from Y capacitors, used for electromagnetic compatibility (EMC) reasons, or parasitic capacitive couplings
7.3.3.2 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 <0.2.1 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 class B electric circuits; see 7.3.3.4. 7.3.4 De-energizalion The voltage class B electric clrcult In question may be de-energized as a protection measure. The monltonng of faults within the drcuit or the detection of events may be used to trigger the de-energizabon. One of the following conditions shall be met for the de-energized circuit. — The voltage shall be reduced to less than 31) V ac. (rrns) for ac. circuits and 60 V d.c. for d.c. cicuits. — The total stored energy of the circuit shal 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 vehicle rnanufac*urer shall conduct an appropnate hazard analyses and establish a set of measures wiuici give sufficient protection against electric shod under single-failure conditions. 7.5 Requirements for insulation If protection is provided by insidation. 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 woriong voltage and temperature ratings of the vehicle and its systems (sea also Clause 4). The insulation shall have sufficient capability to withstand the usual voltage. Compliance shall be tested in accordance with 8.3.