This Regulation provides uniform provisions for approval of vehicles of categories M₁–M₃ and N₁–N₃ equipped with electric traction chain powertrain retrofit systems to be converted into pure electric vehicles (EV) or Hydrogen Fuel Cell Vehicles (HFCV). Retrofit system manufacturers must submit applications including descriptions of the retrofit system, original parent vehicle, modifications, compliance verification, application range, installed samples, authorized installers, and conversion plates. Type approval requires meeting general requirements for design, construction, durability, and failure communication, plus specific requirements in Annexes 5A for EVs and 5B for HFCVs. Only authorized installers may perform conversions, and manufacturers must provide installation documents and end-user manuals.