Document ID: chunk:federal_register_of_legislation:F2023L01529:body:0:p15
Version: federal_register_of_legislation:F2023L01529
Segment Type: other
Provision Reference: 
Character Range: 41961–45070

be provided.
         The device should enable connection to the earth ground before exterior voltage is applied to the vehicle and retain the connection until after the exterior voltage is removed from the vehicle.
         Compliance to this requirement may be demonstrated either by using the connector specified by the car manufacturer, or by analysis.
         5.1.3. Isolation resistance
         This paragraph shall not apply to chassis connected electrical circuits where the maximum voltage between any live part and the electrical chassis or any exposed conductive part does not exceed 30V AC (rms) or 60 V DC.
         5.1.3.1. Electric power train consisting of separate Direct Current- or Alternating Current-buses
         If AC high voltage buses and DC high voltage buses are galvanically isolated from each other, isolation resistance between the high voltage bus and the electrical chassis shall have a minimum value of 100 Ω/volt of the working voltage for DC buses, and a minimum value of 500 Ω/volt of the working voltage for AC buses.
         The measurement shall be conducted according to Annex 4A "Isolation resistance measurement method for vehicle based tests".
         5.1.3.2. Electric power train consisting of combined DC- and AC-buses
         If AC high voltage buses and DC high voltage buses are galvanically connected isolation resistance between the high voltage bus and the electrical chassis shall have a minimum value of 500 Ω/volt of the working voltage.
         However, if all AC high voltage buses are protected by one of the 2 following measures, isolation resistance between the high voltage bus and the electrical chassis shall have a minimum value of 100 Ω/V of the working voltage:
              (a)  Double or more layers of solid insulators, barriers or enclosures that meet the requirement in paragraph 5.1.1. independently, for example wiring harness;
              (b)  Mechanically robust protections that have sufficient durability over vehicle service life such as motor housings, electronic converter cases or connectors;
         The isolation resistance between the high voltage bus and the electrical chassis may be demonstrated by calculation, measurement or a combination of both.
         The measurement shall be conducted according to Annex 4A "Isolation resistance measurement method for vehicle based tests".
         5.1.3.3. Fuel cell vehicles
         If the minimum isolation resistance requirement cannot be maintained over time, then protection shall be achieved by any of the following:
              (a)  Double or more layers of solid insulators, barriers or enclosures that meet the requirement in paragraph 5.1.1. independently;
              (b)  On-board isolation resistance monitoring system together with a warning to the driver if the isolation resistance drops below the minimum required value. The isolation resistance between the high voltage bus of the coupling system for charging the REESS, which is not energized besides during charging the REESS, and the electrical chassis need not be monitored. The function of