6.10. If the motor is air cooled, all ventilation holes must be small enough to prevent the passage of a 12mm diameter spherical test object through all holes.
6.11. When an electrical motor casing is rotating around the stator, a scatter shield must be included to surround the rotating parts of the motor. The shield must be constructed from min 2mm steel or 3mm thickness aluminium alloy. Does not apply to motors fully enclosed in the transmission housing.
6.12. All motor and inverter connections that use bolted HV terminals must be fitted with moulded insulated terminal covers that are sealed to satisfy a minimum IP65 rating.
6.13. All HV power electronics on the Vehicle( including inverter, motor, charger and DC / DC converter must be designed to work safely at the maximum voltage on the Power Bus.
Rechargeable Energy Storage System( RESS)
7. General 7.1. The RESS must be comprised of a maximum of 2 separate traction battery enclosures per Vehicle. 7.2. Capacitor and flywheel energy storage systems are prohibited.
7.3. For Bespoke EVs the maximum total power going out of the RESS at any time is limited to 500kW, except for Drag Racing where the limit is 1MW.
7.4. For National Type Approved EVs the power out of the RESS may not exceed the homologated power.
7.5. For Bespoke EVs the maximum voltage on the Power Bus must never exceed 900V, except for Drag Racing where the limit is 1000V.
7.6. For National Type Approved EVs the maximum voltage must not exceed the homologated maximum voltage.
7.7. The RESS must include appropriately specified fuses or circuit breakers to prevent over-current in the event of short circuit. The protection devices must be located inside the RESS as close as possible to the main power bus connectors.
7.8. The RESS must be capable of being isolated from the Power Circuit by at least two independent systems( e. g. contactor or a manually operated Service Switch). There must be at least one manually operated system and one automatic system( under control of the BMS or Electronic Control Unit). The Service Switch may be a High Voltage( HV) or Low Voltage( LV) device. Any HV device should be orange and designed such that no HV potential is exposed when the device is operated / removed. If HV Service switches are used, they must be fitted into each battery pack. If a LV switch is used, only one is required( preferably mounted on one of the battery packs). The location of the Service Switch( es) should be clearly marked.
8. Enclosure
8.1. The RESS must be installed within the survival cell, passenger compartment, engine compartment or boot of the Vehicle. Underfloor installation of the RESS is permitted if full impact protection is provided to meet the 60kN FIA impact energy requirements. Full details of the impact protection must be provided to ASN 3 months prior to the Vehicle inspection.
8.2. The RESS must not be used as a stressed member.
8.3. Calculations must be provided to the ASN 3 months prior to the vehicle inspection to confirm that mechanical and electrical safety is ensured in a crash. The RESS may be required to pass a crash test defined by the ASN. See ASN website for an example calculation for a battery module and battery pack
8.4. The RESS enclosure must be to a minimum rating of IP65.
8.5. Modules must be mechanically secured inside a metallic or composite enclosure. Any covers or access panels must be sealed and secured with fasteners requiring tools to remove.
8.6. The RESS must be designed to prevent short circuit of the conductive parts. In the event of compartment or component deformation, the design must ensure that no fluids enter the cockpit / Passenger compartment.
Motorsport UK 2025 National Competition Rules Version 11
Chapter 7 Appendix 11- Electrified Vehicles 283