A single-pole or multi-pole device for low-voltage systems, in particular a circuit breaker or a disconnector, which comprises: an outer casing containing for each pole at least one fixed contact and at least one mobile contact that can be coupled to/uncoupled from one another; a rotating element, defined by a shaped body comprising at least one seat for each pole of said switch, said seat being designed to house at least one mobile contact of a corresponding pole; a control mechanism operatively connected to said rotating element for enabling movement thereof; reinforcement elements positioned in said at least one seat of said mobile contact.