The chassis wiring system shall be of sufficient capacity to meet the electrical demand of the vehicle. Chassis and body wiring shall be protected with circuit breakers or field effect transistors. Battery or Batteries. The storage battery or batteries shall: Be furnished by the chassis manufacturer; Be of sufficient capacity to supply all electrical requirements; and Have at least a total of 1,000 cold cranking amperes measured at 0°F. Mounting. The battery or batteries shall be mounted on the outside of the engine compartment. The body manufacturer shall permanently mount the battery or batteries on a sliding tray. One-piece 00 gauge battery cables shall be provided by the manufacturer. The cables shall be of a length to permit the full travel of the battery and tray. The battery cables, if passed through holes in metal, shall be protected by nonconductive grommets. The battery or batteries may be mounted in the engine compartment on rear-engine vehicles. Alternator. The alternator shall be of sufficient output to meet the electrical demand of the vehicle. A dual belt drive or equivalent shall be used. Voltmeter. A graduated voltmeter is required.