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. Circuit breakers trip and shut 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.