A power circuit breaker unit has first and second arcing contact pieces. A contact gap is formed between the arcing contact pieces. A switch gas channel of the circuit breaker unit joins the contact gap to the surrounding area of the circuit breaker unit for removing a switch gas from the contact gap. Several barriers that increase a flow resistance are arranged successively, spaced from one another, in the switch gas channel. At least one of the barriers is arranged between a first pipe section, which is surrounded by a second pipe section, and the second pipe section.