Arc extinguishing chamber for an electrical protective device and electrical protective device with at least one such arc extinguishing chamber

Description

[0001] The present invention relates to the field of electrical protection circuits and more particularly to electrical protection devices, such as circuit breakers, comprising an arc breaking chamber and has as its object an arc breaking chamber for an electrical protection device and an electrical protection device comprising at least one such breaking chamber.

[0002] We know that electrical protection devices, such as circuit breakers, interrupt the flow of electric current in an electrical circuit, for example, within a domestic or industrial electrical distribution network. This interruption, triggered by the electrical protection device when it detects a fault or incident, such as a short circuit or overload, in said electrical circuit, protects power lines, equipment, and / or people.

[0003] These electrical protective devices include connectors for connection to the electrical circuit, a protective mechanism, generally of the bimetallic strip and / or thermal relay and / or electronic circuit type, for detecting a fault, at least one pair of electrical contacts capable of being separated to interrupt the electrical current, a tripping mechanism for separating these contacts, and a protective mechanism for detecting a fault and, upon detection, controlling the separation of the contacts. These electrical protective devices also generally include a handle for manually switching the protective device on or off and for indicating its status.

[0004] A known problem with these electrical protective devices is the formation of an electric arc at the contacts when they separate, allowing current to pass between them. Furthermore, when the energy or temperature of the electric arc is high, particularly at its core, the arc, which is a plasma or ionized gas, can damage the contacts by vaporizing the metal and ejecting molten material.

[0005] To overcome this drawback, electrical protective devices also include at least one arc-breaking chamber to extinguish the electric arc. Such an arc-breaking chamber comprises a vertical stack of flat metal plates held parallel to each other by side walls, also known as cheeks or flanges, which define two opposite sides of the chamber. These plates, also called separators or plates, break the electric arc into as many arcs as there are spaces between two plates, causing the electric arc to lengthen. They also absorb or store at least some of the energy produced by the electric arc.The plates thus make it possible to extinguish the electric arc or to contribute to its extinction and therefore to the definitive interruption of the current by opening the contacts.

[0006] However, these breaking chambers do not always give satisfactory results because the electric arc tends to remain for a prolonged period at the entrance of the breaking chamber, at the junctions between the plates and the flanges of the breaking chamber, which leads to erosion of the flanges resulting in premature wear of the breaking chamber, reducing its effectiveness and the reliability of the electrical protection device.

[0007] Document EP3236482A1 describes a circuit breaker-type electrical protective device comprising a breaking chamber for extinguishing an electric arc formed during the separation of separable electrical contacts connected to the input and output terminals of an electric current, and which also provides a remedy for this drawback. The electrical breaking chamber exhibits increased durability and improved wear resistance when the circuit breaker is used for low voltages and high currents. The breaking chamber comprises a stack of spaced separating plates and side walls (flanges) arranged on either side of the stack. The separating plates are fixed to the side walls by being joined to them along their lateral edges.The breaking chamber also includes protective elements located inside the chamber, along the side walls on either side of the stack, at the junctions between the side walls and the separating plates in the front portion of the chamber facing the electrical contacts. These protective elements cover the corners of the separating plates in the front portion, adjacent to the side walls, thus separating these corners from the electrical contacts. The protective elements thus prevent the electric arc from damaging the flanges of the breaking chamber, particularly when the electric arc remains for an extended period at the entrance of the breaking chamber. Furthermore, the concave shape of one side face of each protective element helps guide the arc towards the central region of the chamber.It also includes a filtration system which is equipped with an exhaust orifice formed in the rear part of the cut-off chamber.

[0008] However, despite the presence of these protective elements, a circuit breaker of the type disclosed in document EP3236482A1 still presents reliability problems, particularly concerning the metal separating plates and maintaining their spacing when an electric arc occurs. Indeed, when an electric arc occurs following the separation of electrical contacts, these metal separating plates are subjected to a magnetic field that attracts them together, causing them to deform or twist. This results in them coming into contact, or even welding, with each other, rendering them inoperative for a second or subsequent interruption of the electrical current. Furthermore, the protective elements are subjected to a powerful blast during the formation of the fragmented electric arc, which can lead to their degradation or even their removal.

[0009] Furthermore, the filtration system is generally integrated into a lid-like assembly secured by metal screws to the rear sides of the cutoff chamber's side walls. These metal screws have the disadvantage of reducing dielectric strength.

[0010] Document EP 1 655 752 A2 describes an arc breaking chamber for an electrical protective device, according to the preamble of claim 1.

[0011] The present invention aims to overcome these drawbacks.

[0012] For this purpose, the arc interruption chamber for electrical protective equipment, according to the present invention, said arc interruption chamber being capable of extinguishing an electric arc formed during the separation / opening of electrical contacts and having a front part intended to be oriented towards said electrical contacts and a rear part, said arc interruption chamber comprising a juxtaposition of metallic separating plates spaced apart and extending along an axis of juxtaposition, at least two flanges facing each other, each having an inner face and delimiting two lateral sides of the arc interruption chamber by being arranged on either side of said separating plates so as to maintain them in a position transverse to the axis of juxtaposition, each separating plate comprising two opposite lateral sides fixed respectively on the inner faces of said flanges,a rear side and a front side located respectively in the rear and front parts of the cutting chamber, is essentially characterized in that it further comprises at least one reinforcing piece disposed on the inner face of each flange, forming an additional thickness extending along the juxtaposition, and in that each lateral side of the separating plates comprises at least one notch provided with at least one retaining element projecting out of said notch, each reinforcing piece being inserted or fitted into the notches of the corresponding lateral sides of the separating plates, and the retaining elements of said notches passing through both the reinforcing piece and the corresponding flange so as to reinforce the maintenance of the spacing between the separating plates when an electric arc occurs.

[0013] The present invention also relates to an electrical protection device comprising connectors for connection to an electrical circuit, at least one pair of electrical contacts capable of being separated from each other to interrupt the flow of electric current between said electrical contacts, at least one tripping mechanism capable of separating said electrical contacts, at least one protection mechanism for detecting a fault and controlling the separation of the electrical contacts, and at least one breaking chamber capable of extinguishing an electric arc formed during the separation of the electrical contacts and having a front part facing said electrical contacts and a rear part allowing the escape of the breaking gases and / or material projections resulting from the appearance of an electric arc during the separation of said electrical contacts.characterized essentially in that the cutting chamber(s) consists of a cutting chamber according to the present invention.

[0014] The invention will be better understood from the following description, which relates to a preferred embodiment, given by way of non-limiting example, and explained with reference to the accompanying schematic drawings, in which: [ Fig. 1 ] is a three-quarter perspective view of the cut-off chamber according to the present invention, in a preferred embodiment comprising protective elements and a filtration cover with intercalated elements, [ Fig. 2 ] is a profile view of the cutting chamber shown on the figure 1 , [ Fig. 3 ] is a perspective and exploded view of the cutting chamber shown on the figure 1 , [ Fig. 4 ] is a longitudinal cross-sectional view of the cutting chamber shown on the figure 1 , [ Fig. 5 ] is a cross-sectional view of the cutting chamber at the level of a cutting chamber separation plate shown on the figure 1 , [ Fig. 6 ] is a cross-sectional view between two separating plates and at the level of a row of intercalated elements, [ Fig. 7 [ ] is a perspective view of the filter cover showing its inner face with the intercalated elements grouped on one part of said face. ] Fig. 8 ] is a perspective view of an electrical protective device comprising breaking chambers according to the present invention.

[0015] The figures show an arc-break chamber for an electrical protective device according to the present invention, said arc-break chamber being capable of extinguishing an electric arc formed during the separation / opening of electrical contacts and having a front portion A intended to be oriented towards said electrical contacts and a rear portion A' (opposite said front portion A). The arc-break chamber comprises: a juxtaposition of metallic separation plates 1, preferably of flat shape, spaced apart and extending along a juxtaposition axis X, and at least two flanges 2 facing each other, each having an internal face 2a, that is to say a face turned towards the interior of the cutting chamber, and delimiting two lateral sides of the cutting chamber by being arranged on either side of said separation plates 1 so as to maintain the latter in position transverse to the juxtaposition axis X.

[0016] Each separation plate 1 comprises two opposing lateral sides 1a fixed respectively on the internal faces 2a of said flanges 2, a rear side 1b and a front side 1c situated respectively in the rear part A' and in the front part A of the cutting chamber.

[0017] According to the present invention, such a breaking chamber further comprises at least one reinforcing piece 3 for strengthening the retention of the separating plates 1 and the spacing between them when an electric arc occurs and is disposed on the inner face 2a of each flange 2, forming an overthickness extending along the juxtaposition, i.e., in the assembled state of the breaking chamber, between the rear sides 1a and the front sides 1b of the separating plates 1. In addition, each lateral side 1a of the separating plates 1 comprises at least one notch 10a provided with at least one retaining element 100a, for example of the type lug or stud, projecting, preferably in the plane of the corresponding separating plate 1, out of said notch 10a.

[0018] Each reinforcement piece 3 is inserted or fitted into the notches 10a of the corresponding lateral sides 1a of the separation plates 1 and the retaining elements 100a of said notches 10a pass through both the reinforcement piece 3 and the corresponding flange 2 so as to reinforce the retention of the spacing between the separation plates 1.

[0019] The notches 10a form on each side of the juxtaposition at least one series of notches 10a extending parallel to the axis of the juxtaposition X. Similarly, each overthickness thus formed extends along the juxtaposition, preferably parallel to the axis of the juxtaposition X.

[0020] It is understood that the overthickness is an increased thickness of the flange 2 over a part of the surface of the corresponding internal face 2a and that each retaining element 100a passes through both the reinforcing piece 3 and the corresponding flange 2 in the direction of their thickness.

[0021] Preferably, as can be seen on the figures 1 , 5 And 6 , each retaining element 100a protrudes out of its notch 10a so as to pass through the corresponding reinforcement piece 3 and flange 2, extending beyond said flange 1 on the outside.

[0022] The reinforcing pieces 43, according to the present invention, make it possible to strengthen the spacing between the separation plates 1. Indeed, each reinforcing piece 43, creating an additional thickness on the inner face 2a of each flange 2, and the retaining elements 100a, passing through both the thickness of the reinforcing piece 3 and the thickness of the flange 2, make it possible to obtain a greater thickness of support for the separation plates 1 at the level of the reinforcing pieces 3, for example, a thickness of approximately 3 mm instead of 1.5 mm without said reinforcing pieces 3. Furthermore, in the preferred case where each retaining element 100a is designed to protrude from the flange 2 on the outside, the protruding portion can be flattened or widened by crushing to securely fix the assembly in the manner of riveting and thus further strengthen the support of the separation plates 1.

[0023] Preferably, each reinforcing piece 43, as can be seen more particularly on the figure 3 It may have an elongated shape, for example rectangular, extending along the juxtaposition, preferably parallel to the juxtaposition axis X, and may be made in one piece or monobloc. In another form, each reinforcing piece 1 may be constituted, in an embodiment not shown in the accompanying figures, by a plurality of elementary reinforcing elements 3, each inserted or fitted into one or more notches 10a.

[0024] The flanges 2, preferably flat, include openings 2d, preferably through-holes, to receive the retaining elements 100a, and the retaining members 3 may include through-holes 3a to receive the retaining elements 100a and allow these elements to pass through both a retaining member 3 and a flange 2, possibly extending beyond the flange 2. The openings 3a in the retaining members 3 are therefore positioned opposite the openings 2d in the flanges 2. (see in particular the figures 1 , 2 , 3 And 5 ).

[0025] Furthermore, the separation plates 1 may include, as is known for example from document EP3236482A1, retaining studs 11a projecting from the lateral sides 1a of the separation plates 1, preferably extending parallel to the plane of said separation plates 1.

[0026] Furthermore, the flanges 2 may include openings 2e, each adapted to receive one of the retaining studs 11a for securely fixing the separating plates 1 to the flanges 2. Each retaining stud 11a on a lateral side 1a of a separating plate 1 may be positioned between the notch 10a of the latter and its rear side 1b. Each opening 2e in a flange 2, adapted to receive one of the retaining studs 11a, may be positioned between the retaining piece 3 and the rear side 2b of said flange 2. The retaining elements 100a, projecting out of the notches 10a, then allow, together with the additional thickness formed by the piece 3 through which said retaining elements 100a pass, for further securing of the position of the separating plates 1 and the spacing between them.

[0027] Preferably, as can be seen particularly on the figures 1 , 3 , 5 And 6Such a breaking chamber may further comprise at least two protective elements 4, each positioned between one of the flanges 2 and the separating plates 1, extending along the joint at the front sides 1c of said separating plates 1. Such a protective element 3 may be of the type described in document EP3236482A1 and will not be described in further detail in this application. Each protective element 3, preferably made from an electrically insulating material, provides good resistance to the blast generated by the electric arc and protects the separating plates 1 by electrically insulating them at their front sides 1c.

[0028] Referring again more specifically to figures 1 , 3 , 5 And 7, we can see that each notch 10a can be made preferentially in a middle part of the lateral side 1a to obtain an even more effective hold.

[0029] In a preferred form, each reinforcing piece 3 has a generally rectangular parallelepiped shape extending parallel to the juxtaposition axis X and each notch 10a has a complementary U-shaped shape. In this case, the retaining element 100a of each notch 10a protrudes out of the notch 10a from the bottom of the U.

[0030] Each flange 2 includes a rear side 2b located in the rear part A' of the cutting chamber.

[0031] Each separating plate 1 is in contact by its lateral sides 1a with the inner face 2a of the flanges 2.

[0032] Furthermore, the present invention may provide that the cutoff chamber further comprises a filtration cover 5 allowing the filtration and exhaust of the cutoff gases resulting from the appearance of an electric arc through the rear portion A' of the cutoff chamber. This filtration cover 5 comprises a filtration chamber 5' and, on either side of the latter, an inner face 5b facing inwards towards the cutoff chamber and allowing the entry of the cutoff gases and material projections resulting from the appearance of an electric arc into said filtration chamber 5', and an outer face 5a allowing the exhaust of said cutoff gases and / or said material projections. The filtration cover 5 is fixed, preferably removably, to the rear sides 2c of the flanges 2.

[0033] If we refer to figures 4 , 6 And 7It can be seen that the present invention can further provide that the inner face 5b of the filter cover 5 also includes intercalated elements 5c, each inserted between two adjacent separating plates 1 in the rear portion A' of the cutoff chamber, so as to reinforce the maintenance of the spacing between the separating plates 1 in the rear portion A' when an electric arc occurs. The intercalated elements 5c are arranged in / on the inner face 5b of the filter cover 5 so as to be distributed over all or part of the length of the juxtaposition.

[0034] The filter cover 5 may include a plurality of inlet ports 5d passing through the inner face 5b to allow the entry of cut-off gases and / or projections into the filter chamber 5'. As can be seen on the figures 4 And 7The intercalated elements 5c can preferably be arranged in the inner face 5b so as to be distributed over only a portion of the length of the juxtaposition, thus optimizing the number of inlet ports 5d while also optimizing the additional spacing between the separating plates 1 created by the intercalated elements 5c. Indeed, it will be understood that the presence of the intercalated elements 5c occupies a surface area of ​​the inner face, preventing the presence of inlet ports 5d on this occupied area. The filter cover 5 may further include exhaust ports 5e passing through the upper face 5a to allow the exhaust of cut-off gases and projections to the outside after passing through the filtration system 5'.

[0035] In a preferred form of assembly or connection, the filter cover 5 is fixed to the rear sides 2b of the flanges 2 by means of an elastic snap-fit ​​assembly, preferably reversible, comprising first elastic snap-fit ​​means 20b disposed on or made in the rear sides 2b of the flanges 2 and second elastic snap-fit ​​means 5f disposed on or made in the inner face 5b of the filter cover 5 so as to cooperate with the latter to achieve the elastic snap-fit ​​assembly.

[0036] The first elastic interlocking / snap-fit ​​means 20b may consist of at least two male parts, for example T-shaped, projecting from the rear side 2b of each flange 2, preferably in the plane of the latter, and the second elastic interlocking / snap-fit ​​means 5f may consist of at least two receiving cavities formed in the inner face 5b of the filter cover 5 so as to receive each of said male parts by elastic interlocking / snap-fit. The vertical arm of the elastically deformable or flexible T allows elastic deformation of the male part 20b when it is pushed during assembly, with a movement in one direction, into the corresponding receiving cavity 5f, and the horizontal arm of the T fits into a recess 50f of said receiving cavity 5f, configured for this purpose, to prevent movement in the opposite direction ( figures 1 , 2 , 3 , 6 And7 ).

[0037] The present invention may provide a configuration of the receiving cavities 5f in the inner face 5b allowing the horizontal branches of the T to exit in order to form a reversible assembly and to allow the filtration cover 5 to be disassembled. For example, the filtration cover 5, as can be seen on the figures 1 , 2 , 3 , 6 And 7The device may comprise two opposing external faces 5g perpendicular to the internal face 5b, and each receiving cavity 5f may be machined in the internal face 5b so as to extend into one of the external faces 5g. This allows the vertical arm of the T to be moved outwards from the external face 5g by elastic deformation of the vertical arm of the T, thereby disengaging the horizontal arm of the T from the housing 50f of said receiving cavity 5f. Of course, other embodiments of the male parts 20b may be considered to achieve a similar effect and result without departing from the scope of the present invention.

[0038] Furthermore, each receiving cavity 5f, as can be seen more particularly on the figure 7 , may include one or more inclined surfaces 51f, in particular in the part of the receiving cavities 5f leading to the housing 50f, this to facilitate the insertion and / or guidance of the male parts 20b in said receiving cavities 5f until the horizontal arm of the T is fitted / clicked into the housing 50f.

[0039] Elastic interlocking / snap-fitting means will be understood as elastic interlocking means or snap-fitting means, these two expressions being similar and often used in English under the expression "snap-fit".

[0040] Such an assembly by elastic interlocking / snap-fitting allows the use of plastic parts instead of metal screws generally used in current switching chambers, the said screws having the disadvantage of reducing dielectric rigidity.

[0041] If we refer more specifically to figures 4 , 5 And6 We can see that the cutting chamber can further include a known arc horn C which facilitates the movement of the electric arc from its entry into the cutting chamber located in its front part A' towards the internal space of the cutting chamber occupied by the juxtaposition of separating plates 1. Such an arc horn C is described for example in document EP3236482A1.

[0042] The present invention also relates to an electrical protection device comprising connectors for connection to an electrical circuit, at least one pair of electrical contacts capable of being separated from each other to interrupt the flow of electric current between said electrical contacts, at least one tripping mechanism capable of separating said electrical contacts, at least one protection mechanism enabling the detection of a fault and the control of the separation of the electrical contacts and at least one breaking chamber capable of extinguishing an electric arc formed during the separation of the electrical contacts and having a front part facing said electrical contacts and a rear part A' enabling the escape of the cutting gases and / or the projections of material resulting from the appearance of an electric arc during the separation of said electrical contacts.

[0043] In accordance with the present invention, in such an electrical protective device as shown in the figure 8 , the or at least one of the cutting chamber(s) consists of a cutting chamber according to the present invention as described above. This can be seen more particularly on the figure 8 such an electrical protective device comprising several breaking chambers, for example three breaking chambers, according to the present invention and visible through their filter cover 5. Each breaking chamber can then be provided so that its front part is turned towards one of the pairs of electrical contacts of the electrical protective device which may comprise several pairs of electrical contacts.

[0044] Thus, such a breaking chamber according to the present invention, or the electrical protection device comprising such a breaking chamber, allows in particular the following improvements compared to known breaking chambers, or electrical protection devices comprising such a breaking chamber: The reinforcing pieces 3, forming raised sections through which the flanges 2 pass, by the retaining elements protruding from the lateral sides of the separation plates 1, improve the maintenance of their spacing when an electric arc appears following the opening / separation of the electrical contacts, and where applicable, the intermediate elements 5c further reinforce the maintenance of this spacing between the separation plates 1 in the rear part A' of the cut-off chamber, the assembly by elastic interlocking / snap-fit, ensuring the fixing or connection between the filter cover 5 and the flanges 2, allowing the use of non-metallic parts in order to increase electrical rigidity and optimize the filtration surface.

Claims

1. Electric arc quenching chamber for an electrical protection device, said quenching chamber being able to extinguish an electric arc formed during the separation / opening of electrical contacts and having a front portion (A) intended to face said electrical contacts and a rear portion (A'), said quenching chamber comprising a juxtaposition of metallic separating plates (1) that are spaced apart from one another and extend along a juxtaposition axis (X), at least two flanges (2) which face one another, each of which has an internal face (2a), and which delimit two lateral sides of the quenching chamber by being disposed on either side of said separating plates (1) so as to hold them in position transversely to the juxtaposition axis (X), each separating plate (1) comprising two opposite lateral sides (1a) respectively fixed to the internal faces of said flanges (2), a rear side (1b) and a front side (1c) located in the rear portion (A') and in the front portion (A), respectively, of the quenching chamber, the quenching chamber moreover comprising at least one reinforcing part (3) disposed on the internal face (2a) of each flange (2) with formation of an overthickness extending along the juxtaposition, and characterized in that each lateral side (1a) of the separating plates (1) comprises at least one slot (10a) equipped with at least one holding element (100a) protruding out of said slot (10a), each reinforcing part (3) being inserted or pushfitted in the slots (10a) of the corresponding lateral sides (1a) of the separating plates (1) and the holding elements of said slots (10a) passing through both the corresponding reinforcing part (3) and the corresponding flange (2) so as to reinforce the maintenance of the spacing between the separating plates (1) when an electric arc appears.

2. Quenching chamber according to Claim 1, characterized in that each holding element (100a) protrudes out of its slot (10a) so as to pass through the corresponding reinforcing part (3) and the corresponding flange (2) and project beyond said flange (2) towards the outside.

3. Quenching chamber according to Claim 1 or 2, characterized in that it moreover comprises at least two protection elements (4) each positioned between one of the flanges (2) and the separating plates (1) and extending along the juxtaposition on the front sides (1b) of said separating plates (1).

4. Quenching chamber according to any one of Claims 1 to 3, characterized in that each slot (10a) is formed in a median portion of the lateral side (1a).

5. Quenching chamber according to any one of Claims 1 to 4, characterized in that each reinforcing part (3) has the overall shape of a rectangular parallelepiped extending parallel to the juxtaposition axis (X) and each slot (10a) has a complementary U shape, and in that the holding element (100a) of each slot (10a) protrudes out of the slot (10a) from the bottom of the U.

6. Quenching chamber according to any one of Claims 1 to 5, characterized in that each flange (2) comprises a rear side (2b) located in the rear portion (A') of the quenching chamber, in that it moreover comprises a filtration cover (5) comprising a filtration chamber (5') and, on either side of the latter, an internal face (5b) that faces the inside of the quenching chamber and enables quenching gases and / or said material projections resulting from the appearance of an electric arc to enter said filtration chamber (5'), and an external face (5a) for discharging said quenching gases and / or said material projections, said filtration cover (5) being fixed, preferably removably, to the rear sides (2b) of the flanges (2), and in that said internal face (5b) comprises spacer elements (5c) each inserted between two adjacent separating plates (1) in the rear portion (A') of the quenching chamber so as to reinforce the maintenance of the spacing between the separating plates (1) in said rear portion (A') when an electric arc appears, said spacer elements (5c) being arranged in the internal face (5b) so as to be distributed over all or some of the length of the juxtaposition.

7. Quenching chamber, according to Claim 6, characterized in that the filtration cover (5) is fixed to the rear sides (2b) of the flanges (2) by means of a snap-fit / elastic push-fit assembly, which is preferably reversible, comprising first snap-fit / elastic push-fit means (20b) disposed on or formed in the rear sides (2b) of the flanges (2), and second snap-fit / elastic push-fit means (5f) disposed on or formed in the internal face (5b) of the filtration cover (5) so as to interact with said second snap-fit / elastic push-fit means to produce the snap-fit / elastic push-fit assembly.

8. Quenching chamber according to Claim 7, characterized in that the first snap-fit / elastic push-fit means (20b) consist of at least two T-shaped male parts protruding from the rear side (2b) of each flange (2) and the second snap-fit / elastic push-fit means (5f) consist of at least two receiving cavities formed in the internal face (5b) of the filtration cover (5) so as to each receive one of said T-shaped male parts by snapfitting / push-fitting.

9. Quenching chamber according to Claim 8, characterized in that the filtration cover (5) comprises two opposite external faces (5g) perpendicular to the internal face (5b) and each receiving cavity (5f) is formed in the internal face (5b) and continues in one of the external faces (5g).

10. Electrical protection device comprising connectors for connection to an electrical circuit, at least one pair of electrical contacts able to be separated from one another to interrupt the flow of the electric current between said electrical contacts, at least one trigger mechanism able to separate said electrical contacts, at least one protection mechanism for detecting a fault and controlling the separation of the electrical contacts, and at least one quenching chamber that is able to extinguish an electric arc formed during the separation of the electrical contacts and has a front portion facing said electrical contacts and a rear portion (A') for discharging quenching gases and / or material projections resulting from the appearance of an electric arc during the separation of said electrical contacts, characterized in that the or at least one of the quenching chamber(s) consists of a quenching chamber according to any one of Claims 1 to 9.