Tested in accordance with ANSI/IEEE certification standards, CBS MaxiVac’s™ Tough Duty™ roll-in replacement circuit breakers include replacement encapsulated Vacuum Interrupters, Inc. pole assemblies that harden breakers against environmental contamination. This variety of Power/Vac® breakers, without any modifications to existing cells or switchgear, work with existing remote racking and switching equipment and do not require any cell or wiring modifications.