Single-pole or multi-pole switching device for low voltage systems comprising: - a case containing at least one pair of contacts that can be reciprocally coupled/ decoupled; - at least one containment structure (20,20B,20C) to contain at least one accessory device of said switching device, said structure comprising means for interfacing with said accessory device; said structure (20, 20B, 20C) further comprising a coupling surface defined on a part of said containment structure (20, 20B, 20C); - at least one accessory device comprising a body that can be inserted in said containment structure (20,20B,20C) and provided with coupling means to couple it to said containment structure (20,20B,20C); - said accessory device comprising operating means to interact with said switching device via said interface means of said at least one containment structure (20,20B,20C), said accessory device being provided with disengagement means operatively connected with said coupling means; - said disengagement means, once activated, freeing said coupling means from said coupling surface to permit the extraction of said accessory device from said containment structure (20,20B,20C); characterised in that: - said coupling means of said accessory device comprise a first lever arm pivoting on a flexible fulcrum portion emerging from a surface of said body of said accessory, said first lever arm comprising a free end which couples to a corresponding coupling surface of said containment structure (20,20B,20C) when said accessory device is inserted in the structure; - said disengagement means comprise a second lever arm provided with an actuation portion, said second lever arm being operatively connected to said first lever arm in order to free, when activated, said free coupling end from said coupling surface of said containment structure (20,20B,20C); - a case containing at least one pair of contacts that can be reciprocally coupled/ decoupled; - at least one containment structure (20,20B,20C) to contain at least one accessory device of said switching device, said structure comprising means for interfacing with said accessory device; said structure (20, 20B, 20C) further comprising a coupling surface defined on a part of said containment structure (20, 20B, 20C); - at least one accessory device comprising a body that can be inserted in said containment structure (20,20B,20C) and provided with coupling means to couple it to said containment structure (20,20B,20C); - said accessory device comprising operating means to interact with said switching device via said interface means of said at least one containment structure (20,20B,20C), said accessory device being provided with disengagement means operatively connected with said coupling means; - said disengagement means, once activated, freeing said coupling means from said coupling surface to permit the extraction of said accessory device from said containment structure (20,20B,20C); - said coupling means of said accessory device comprise a first lever arm pivoting on a flexible fulcrum portion emerging from a surface of said body of said accessory, said first lever arm comprising a free end which couples to a corresponding coupling surface of said containment structure (20,20B,20C) when said accessory device is inserted in the structure; - said disengagement means comprise a second lever arm provided with an actuation portion, said second lever arm being operatively connected to said first lever arm in order to free, when activated, said free coupling end from said coupling surface of said containment structure (20,20B,20C);