ISO 6469-3:2011 pdf free download – Electrically propelled road vehicles一 Safety specifications – Part 3: Protection of persons against electric shock.
7.3.1 Potential equalization
As a general rule, exposed conductive parts of 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 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 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, barriers and/or 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 I Isolation resistances below the required minimum values can occur due to deterioration of fuel cell (FC) systems’ cooling liquids or of certain battery types.
NOTE 2 Coordination between multiple isolation monitoring systems can be necessary, e.g. during charging.
NOTE 3 The isolation resistance is approximately zero for a voltage class B electric circuit conductively connected to the grid.
NOTE 4 Additional layer(s) of insulation and double or reinforced insulation include, but are not limited to, those for voltage class B wiring.
NOTE 5 The rigid barriers/enclosures 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 barriers/enclosures to meet both basic and single-failure protection requirements.
7.3.3 Capacitive couplings
7.3.3.1 Capacitive couplings between a voltage class B potential and electric chassis usually 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 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 class B electric circuits; see 7.3.3.4. 7.3.3.3 For a.c. body currents caused by such capacitive couplings when touching a.c. class B voltage one of the following options shall be fulfilled: a.c. body current shall not exceed 5 mA when measured in accordance with IEC 60950-1; alternative mechanical or electrical measures for a.c. voltage class B electric circuits; see 7.3.3.4. 7.3.3.4 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 enclosures in addition to the basic protection; rigid barriers/enclosures with sufficient mechanical robustness and durability, over the vehicle service life.