Each PDU contains a circuit breaker for each outlet group. These circuit breakers are safety devices to protect equipment from damage and you from personal injury. A circuit breaker trips and shuts the power off to an outlet group when it detects an overloaded circuit, a short circuit, or another fault condition.
When operating normally in the On (|) position, the circuit breakers are flush with the side of the PDU. When tripped to the Off (0) position, the circuit breakers extend beyond the side of the PDU.
Caution - To prevent injury and equipment damage, always determine the cause of a tripped circuit breaker before resetting it.