Siemens sirius 3rv1 circuit breaker 3rv1011 3rv1021 3rv1031 siemens 3rv1021 4aa10 the siemens 3rv1021 4aa10 sirius circuit breaker can be used as type e self protected manual combination starters per ul508 or as components in group installation to turn motors on and off the device has a built in heater element that provides overload protection and magnetic trip elements to protect the motor when the 3rv is used as a component in a group installation multiple msps motor starter protec