12.21. 12:21 Every part of the electrical equipment must have a minimum insulation resistance between all live components and earth of 500 Ohms per volt. The measurement of the insulation resistance must be carried out using a DC voltage of at least 100 volts.
12.22. 12:22 Unless the function is already provided by the BMS a proprietary isolation surveillance system must be used to continuously monitor the status of the isolation barrier between the voltage class B( 2.9) system and the Chassis while the HV system is energised.
12.23. If not part of the BMS the proprietary isolation surveillance system must be located within the RESS enclosure and wired in series with the main RESS contactors. If an isolation fault is detected, the system shall open the circuit breaker automatically and trigger the“ Danger” state of the RESS Status Indicator. Full details of the isolation surveillance system must be provided to ASN 3 months prior to the Vehicle inspection.
12.24. The Competitor must provide a detailed“ Emergency Services Guide” documenting all aspects of the HV system including component locations and details of the standard and emergency HV isolation procedures. This document should be structured in the same way and have similar content to the guides provided by OEM’ s for production EVs and must be provided to ASN 3 months prior to the Vehicle inspection.
12.25. See App. 13 Diagram 3 for an example of the EV System Schematic showing all components and connections. The Vehicle specific version must be provided to ASN 3 months prior to the Vehicle inspection.
12.26. On Vehicles without a 12v alternator, a DC / DC converter of suitable power rating must be provided to charge the auxiliary battery and electrical system.
12.27. The auxiliary battery must never be used to recharge the RESS.
SAFETY EQUIPMENT. 13. Driver master switch
13.1. All Vehicles must be equipped with a general circuit breaker of sufficient capacity and which can be operated easily by a switch from the driver’ s seat when the Driver is seated in a normal and upright position, with the safety belts fastened and the steering wheel in place and from the outside to cut off all electric transmission devices.
13.2. This switch MUST act as a General Circuit Breaker that interrupts ALL electrical transmission between the RESS and all other HV circuits by means of a spark-proof circuit breaker providing galvanic switching which MUST NOT be short- circuited by any components such as a pre-charge resistor. Low power batteries provided for low voltage circuits, for example auxiliary circuits, do not have to be isolated by the general circuit breaker provided that they are completely isolated from the main power accumulators.
13.3. In the event that the circuit breaker is activated, the HV potential, outside the RESS, must drop below 60V DC with 4 seconds.
13.4. Specifications for the General Circuit Breaker are laid down in Appendix J – Article 253 18.17.
14. Fire Extinguisher
14.1. All Vehicles must be equipped with an electrically operated plumbed in extinguishing system in accordance with App. 6 Art. 1.1. Only systems with an extinguishing medium proven to not create a conductive atmosphere and in compliance with the below list are authorised:
• Novec 1230 or FX G-TEC FE36. 15. Extinguisher switches
15.1. The system must have three points of triggering, one for the Driver and two exterior actuators. These external actuators must be situated at the base of the main rollover structure on both sides of the Vehicle for a single seater or at the lower corners of the windscreen for a closed cockpit Vehicle.
15.2. A means of triggering from the outside must be combined with the general circuit breaker switches.
Motorsport UK 2025 National Competition Rules Version 11
Chapter 7 Appendix 11- Electrified Vehicles 286