The CVB 15/08 series is a vacuum circuit breaker which is designed specifically to be considered as the main electrical switch and a device protecting the AC locomotives and its electrical multiple units. The power needed to turn the CVB on is kept through a spring. It only takes a minimum amount of energy to unlock the spring release latch and free the energy stored. When the supply is already applied, the spring then recharge itself in not more than 10 seconds. If there is no voltage applied, chances are the vacuum circuit breaker turns off and the springs maintains its charged and ready-to-be used switching operation or technique. There is no need for a secondary energy supply for the vacuum circuit breaker for its main energy supply is enough to power up the whole system.