DEVICE FOR OVERVOLTAGE PROTECTION WITH HIGH INGRESS PROTECTION, PARTICULARLY FOR THE PROTECTION OF LED STREET LIGHTING AND A METHOD OF ITS PRODUCTION

Abstract

 The invention relates to a device for overvoltage protection with high ingress protection, particularly for the protection of LED street lighting having a housing (1), comprising a varistor (4), which is by each of its leads (4d, 4f) connected to a protected electrical circuit, whereby at one lead (4f) is soldered by solder with a set temperature of melting an uninsulated end (8a) of an electrical conductor (8), with which is aligned a spring (9) for deflecting the uninsulated end (8a) of the electrical conductor (8) away from the lead (4f) of the varistor (4) after melting the solder. The end portion (8b) of the electrical conductor (8) with the uninsulated end (8a), the lead (4f) of the varistor (4), their soldered connection with an adjustable temperature of melting and the spring (9) are arranged in a cavity (50) within the housing (1), which is separated in an airtight manner from the surrounding environment, whereby the other elements of the device are also separated in an airtight manner from the surrounding environment.
The invention also relates to a method of manufacturing a device for overvoltage protection with high ingress protection, particularly for the protection of LED street lighting.

Description

Technical field

[0001] The invention relates to a device for overvoltage protection with high ingress protection, particularly for the protection of LED street lighting, comprising a varistor, which is by each of its leads connected to a protected electrical circuit, whereby at one lead an uninsulated end of an electrical conductor is soldered with a solder having a set melting temperature, the uninsulated end of the electrical conductor being aligned with a spring for deflecting it away from the varistor lead after melting the solder.

[0002] The invention also relates to a method of production of a device for overvoltage protection with high ingress protection, particularly for the protection of LED street lighting, comprising a varistor, which is by each of its leads connected to a protected electrical circuit, whereby at one lead is soldered by solder with a set temperature of melting an uninsulated end of an electrical conductor, with which is aligned a spring for deflecting the uninsulated end of the electrical conductor away from the lead of the varistor after melting the solder.

Backaround art

[0003] In the field of lighting the situation with regard to the used sources of light has been dramatically changing recently, when LED systems have been used as illumination sources on a mass scale. This is caused especially by a considerable reduction in the price of LED, whereby a vital role is played by a low consumption of electrical energy when using LEDs in comparison with other light sources.

[0004] The trend towards using LEDs as light sources can be seen also in street lighting, i.e. the lighting of streets, squares, roads, sites, etc., which, however, provide additional and specific conditions affecting the functionality, durability and resistance of the street lighting system. Since the light sources of street lighting are located on columns outdoors and the wiring of electrical energy for street lighting is led either in the air or under the ground for relatively long distances, there are specific conditions for the protection of the light sources of street lighting from overvoltage. These requirements then affect the functionality and durability of a device for overvoltage protection, which, apart from the desired performance, must also meet the required conditions of resistance to the external environment, particularly the so-called ingress protection indicated by the value IP.

[0005] As a rule, a high degree of protection IP 65 or IP 66 is required for outdoor use in street lighting, whereby the device for overvoltage protection must also meet electrical, electro-mechanical and physical requirements, which are set, e.g., by EN 616 43-11:2013.

[0006] The above-mentioned EN, for example, requires that the elements limiting voltage, e.g. varistors, in case of increased temperature due to the electrical current flowing through them, are automatically disconnected from the protected circuit, i.e. from power. This requirement is based on the fact that varistors, which have been long connected to the electrical network, i.e. the network, which they protect from the effects of overvoltage, are exposed to the effects of overvoltage pulses. The varistors loaded in this manner tend to age, which manifests itself in a gradual growth of the amount of electrical current flowing through them. As a result of the electrical current passing through the varistor, the varistor is heated, which might even lead to overheating the varistor and a subsequent short circuit. A short circuit of the varistor is to be prevented by automatic disconnection of the varistor from the protected circuit in sufficient time before it reaches a critical temperature.

[0007] A number of design solutions are known which are used for timely automatic disconnection of the varistor from the protected circuit. Nevertheless, these solutions are more likely known for usage under usual conditions which do not require a high degree of protection IP65 or IP66, since such high ingress protection is usually solved by casting the entire electrical system with an insulating casting material. Thus the whole electrical system is wrapped in an impervious manner in the insulating material and the elements of the system are protected from climatic factors, such as humidity, etc. Such solutions, when the whole device for overvoltage protection is cast with an insulating material, are already known. However, due to the usage of insulating casting materials, the range of options of means for timely automatic disconnection of the varistor from the protected circuit is considerably limited, since it is not only necessary to ensure heat transfer from the varistor to a thermal disconnecting device but, above all, the thermal disconnecting device must be able to withstand high-impulse currents and, generally, a large impulse load, as can be expected in street lighting systems.

[0008] It is known that a thermal fuse is used for automatic disconnection of the varistor from the protected circuit. The thermal fuse is composed of a totally enclosed housing into which are fed mutually parallel electrical leads (L, N). The ends of the leads are interconnected by an electrically conductive cross-piece, which is butt-soldered to the front surface of the leads. A spring rests upon the cross-piece, acting upon the cross-piece in a direction away from the front surface of the leads, whereby in this direction in the housing behind the cross-piece is formed a free space big enough for creating a sufficient insulation gap between the crosspiece displaced by the spring to this rear position and the front surface of the leads. The cross-piece is moved away to its rear position by the spring only after melting the solder, by which it is soldered to the front surface of the leads, whereby the melting process is caused by the heat transfer from the varistor via the housing of the thermal fuse, which is mounted on the side surface of the varistor. The thermal fuses thus arranged, however, have been developed for electrical appliances with low demands for energy, and therefore they are basically little resistant to impulse currents and by its relatively low impulse load capacity they also limit the device for overvoltage protection, in which they are optionally used. So as to increase the impulse load capacity of this construction concept, it would be necessary to form a relatively sizable housing with sufficient openings of the conductors and especially with a sufficient size of the soldered areas of the cross-piece with both conductors and also with corresponding distances between the disconnected ends. Nevertheless, this is limited by the size of the protected device and the requirements for the size of the device for overvoltage protection. This solution to the thermal fuses and the device for overvoltage protection is therefore intended for normal operating conditions (usually with IP 20). If this construction concept is provided with a high degree of ingress protection, this is realized by casting or wrapping the whole assembly of the varistor with the thermal fuse in one block of the insulating casting material, from which protrude only electrical conductors for connecting the device for overvoltage protection to the protected circuit, i.e. to the electrical wiring. In essence, this is how the device for overvoltage protection is created. On the one hand, the device for overvoltage protection meets the requirements for high ingress protection, but, on the other hand, it is inadequate from the electrical and energetic point of view, namely due to the use of the thermal fuse, which in principle does not have the desired high resistance to impulse load, which occurs in the systems of street lighting with LED light sources. The varistors alone, which are used in practice in these devices for overvoltage protection, do not have adequate properties.

[0009] Furthermore, it is known that a chemical substance is used for automatic disconnection of the varistor from the protected circuit, the chemical substance being applied to the side surface of the varistor body under its own epoxy insulating coating of the varistor. During the varistor being heated to a set temperature, this material increases its volume, by which means it acts mechanically upon the defined electrical connection between the protected circuit and the varistor, causing its interruption, i.e. disconnection of the varistor from the protected circuit. Typically, this substance causes disconnection of the electrode of the varistor from the side wall of the varistor body. The disadvantage of this solution is the fact that after the device for overvoltage protection with the disconnecting device is totally cast with the insulating casting material, when all the components of the device are hermetically sealed with the insulating casting material, it is the insulating casting material that puts up increased resistance to expansion (increase in volume) of the disconnecting temperature sensitive chemical substance. That results in insufficient separation of the contacts of the device for overvoltage protection and thus also insufficient voltage strength between the disconnected electrode and the varistor body, and so the reliability of safe disconnection is considerably reduced. Another drawback of this solution its difficult applicability for high-performance varistors, which also require sufficiently robust embodiment of the disconnecrted elements, e.g. sufficient thickness of the material of the elements being disconnected, etc., which manifests itself in higher mechanical resistance of the parts being disconnected and higher requirements for the force acting during the process of disconnecting. This further reduces the efficiency and reliability of the disconnection, i.e. automatic disconnection of the varistor from the protected circuit.

[0010] Practical experience with using LED street lighting and the rating of the device for their overvoltage protection has brought a great deal of knowledge, especially due to summer storms, in terms of not only electrical, but also the mechanical sizing of the device for overvoltage protection of street lighting with LED elements. Insufficient rating of the device for overvoltage protection under extreme conditions, such as summer storms, which, however, are far from being rare, results in premature damage of the protective elements and subsequent damage of the LED light body. Removing the consequences of these failures afterwards is very expensive.

[0011] In principle, the background art involves using known inventions for normal operating conditions with IP 20 and their adaptation to demanding weather conditions by high ingress protection.

[0012] Known are also other embodiments of thermal disconnecting devices,i.e. devices which are used for automatic disconnection of the varistor from the protected circuit if the temperature of the varistor reaches a certain set level. In these known devices an uninsulated end of one electrical conductor is soldered with a solder having a set melting temperature to one lead of the varistor and is connected directly or via an intermediate element to one end of a draw or compression spring, which in the case of melting the solder ensures deflecting the uninsulated end of the electrical conductor away from the lead of the varistor and disconnecting the varistor safely from the protected circuit. Although these arrangements enable to rate the thermal disconnecting devices to withstand even a high level of impulse load, their disadvantage is that casting with an insulating casting material would be impossible, since this material casts also the movable parts of the thermal disconnecting devices, which then cannot move and thus the thermal disconnecting devices are not disconnected and the varistor is not disconnected from the protected circuit. This leads to a short circuit of the varistor with all the consequences.

[0013] The goal of the invention is to eliminate or at least reduce the drawbacks of the background art, especially to provide a high-performance device for overvoltage protection with high ingress protection, at least IP 65, which will at the same time meet the requirements of EN 61643-11.

Principle of the invention

[0014] The aim of the invention is achieved by a device for overvoltage protection with high ingress protection, whose principle consists in that the end portion of an electrical conductor with an uninsulated end, the lead of a varistor, their soldered connection with a set melting temperature and a spring are arranged in a cavity which is separated in an airtight manner from the surrounding environment, whereby the other elements of the device are also separated in an airtight manner from the surrounding environment.

[0015] The principle of the method of production of a device for overvoltage protection with high ingress protection consists in that the device is cast with an insulating casting material in two stages, whereby before the first stage of casting all the parts of the device for overvoltage protection are assembled into a functional whole, which is placed in a housing, whereupon the first stage of casting is performed, during which the insulating casting material is cast to a height slightly above the upper surface of the varistor, by which means all the cavities in the housing are filled, except the cavity of the casing, and after hardening of the insulating casting material from the first stage of casting, the second stage of casting is carried out, when all the remaining electrically conductive parts of the device are cast with the casting material, including at least the bottom part of the side walls of the casing.

[0016] The device according to the invention is composed of a high-performance device for overvoltage protection, which allows substantially higher energetic load without damage in comparison with the background art and thus enables to reduce considerably the occurrence of failures of the street lighting with LED lights caused by overvoltage in the power distribution network. The method according to the invention enables efficient production of high-performance devices for overvoltage protection.

Description of drawings

[0017] The invention is schematically represented in the drawings, where Fig. 1 shows a partial section of a device for overvoltage protection with a cavity for a thermal disconnecting device Fig. 2 is a plan view of an arrangement of a device for overvoltage protection with a cavity for a thermal disconnecting device with not disconnected thermal disconnecting device, Fig. 3 is a plan view of an arrangement of the device for overvoltage protection with a cavity for the thermal disconnecting device with the disconnected thermal disconnecting device , Fig. 4 shows a cross-section of a flat high-performance varistor with electrodes and an epoxy insulating coating, Fig. 5 illustrates an arrangement of the cavity for thermal disconnecting device perpendicularly to the side wall of the varistor, Fig.6 shows an arrangement of the cavity for thermal disconnecting device inclined to the side wall of the varistor, Fig. 7 shows an arrangement of the cavity for thermal disconnecting device inclined above the side wall of the varistor, Fig. 8 represents an exploded view of an arrangement of the device according to the invention without an insulating casting material, Fig. 9 is a view up of the casing turned upwards through the cavity and Fig. 10 is a cross-section of a block of two parallel-connected varistor units.

Specific description

[0018] The invention will be described using an example of embodiment of a device for overvoltage protection with high ingress protection, which comprises a housing 1 with a cover 15, in which ndividual elements of the device for overvoltage protection are located. From the housing 1 protrude insulated electrical conductors 7, 8, 12, by which the device is connected to the protected electrical circuit.

[0019] In the housing 1 is mounted an aerial discharge 13, which is by one contact connected to an uninsulated end of the earthing conductor 12. By its other contact the aerial discharge 13 is connected to an uninsulated end of a neutral conductor 7 and, at the same time, also to an uninsulated portion of the first lead 4d of a flat varistor 4. The uninsulated portion of the second lead 4f of the flat varistor 4 is in the illustrated example of embodiment bent perpendicularly to the surface of the varistor 4 in a direction upwards above the varistor 4. In the illustrated example of embodiment, the neutral conductor 7 is connected to the second lead 4d of the varistor 4. In the illustrated example of embodiment, one varistor unit is used as a varistor 4. In the example of embodiment shown in Fig. 10, a block of two varistor units connected in parallel is used as a varistor 4, with outlet leads 4d and 4f. In an unillustrated example of embodiment, a block of more than two parallel-connected varistor units with outlet leads 4d and 4f are used as a varistor 4.

[0020] As is illustrated in Fig. 4, each of the leads 4d, 4f of the varistor 4 is a part of one of the electrodes 4b, 4c, whereby each electrode 4b, 4c in an electrically and thermally conductive manner attached to one side wall 4a of the varistor 4. With the exception of the uninsulated leads 4d, 4f, the varistor 4 is provided with an electrically insulating coating 4g, e.g. with epoxy material or another suitable electrically insulating coating.

[0021] In the illustrated example of embodiment, the varistor 4 has a square ground plan and both leads 4d, 4f are located on one side wall of the ground plan of the varistor 4, one of the leads 4d, 4f is located by one corner of the varistor 4 and the other of the leads 4d, 4f is located by the other corner of the varistor 4.

[0022] On the upper surface of the varistor 4 is mounted a casing 5, which has an upper surface 51 and side walls 52 and which in the ground plan corresponds to the outlines of the ground-plan of the varistor 4. The casing 5 in the illustrated example of embodiment lies with its major part, in particular with three of its side walls 52 on the upper surface of the varistor 4 and only on the side of the leads 4d and 4f, the varistor 4 overlaps the ground plan of the varistor 4. The other lead 4f of the varistor 4 passes from the bottom to the cavity 50 created between the casing 5 and the upper surface of the varistor 4. One side wall 52 of the casing 5, which is arranged outside the ground plan profile of the varistor 4, i.e. the wall which overlaps the ground plan profile of the varistor 4, is longer than the other side walls 52 of the casing 5. As is illustrated in Fig. 9, this longer side wall 52 goes downwards as far as under the level of the upper surface of the varistor 4. Along the side wall 1a of the housing 1, which is more distant from the second lead 4f of the varistor 4, in the illustrated example of embodiment, i.e. through the space between the side wall 1a of the housing 1 and the contact of the aerial discharge 13 connected to the neutral conductor 7 and at the same time also to the first lead 4d of the flat varistor 4, the phase conductor 8 extends as far as to the corner of the varistor 4 (seen in the ground plan). Near the corner of the varistor 4 is situated a phase conductor 8 bent by a bending 80 upwards, which leads leads to the cavity 50 between the casing 5 and the upper surface of the varistor 4 as far as to the level of the upper surface of the varistor 4, where the phase conductor 5 is again bent by a bending 10 in a direction parallel to the surface of the varistor 4 and leads in a direction along the side edge of the varistor 4 to the second lead 4f of the varistor 4. The end portion 8b of the phase conductor 8 is stripped near the second lead 4f of the varistor 4 and with this uninsulated end 8a it is led parallel to the surface of the second lead 4f of the varistor 4. The uninsulated end 8a is connected to the second lead 4f of the varistor 4 by solder with a set melting temperature, which is determined by the required temperature of the automatic disconnecting of the varistor 4 from the protected circuit and corresponds to the safe temperature of the varistor 4 before the short circuiting of the varistor 4. The end portion 8b of the phase conductor 8 is further connected to one end of a draw spring 9, whose other end is mounted on the casing 5 in a distance from the first end of the spring 9, e.g. on a protrusion 53. The whole spring 9, similarly to the end portion 8b of the phase conductor 8 is situated in the cavity 50 between the casing 5 and the varistor 4. The force of the spring 9 acting upon the end of the phase conductor 8 is such that after the melting of the solder connecting the second lead 4f of the varistor 4 and the uninsulated end 8a of the phase conductor 8 it can deflect the uninsulated end 8a of the phase conductor 8 away from the second lead 4f of the varistor 4.

[0023] In the illustrated example of embodiment, the phase conductor 8 is composed of a copper cable or wire rated for the expected load to withstand, especially the impulse load. In an unillustrated example of embodiment, the end portion of the phase conductor 8, which is situated in the cavity 50 between the casing 5 and the varistor 4, which is formed by flat copper conductor (tin), which is soldered to the second lead 4f of the varistor 4 and is connected to one end of the draw spring 9.

[0024] In the illustrated example of embodiment, a system 14 of optical signalization of overvoltage protection function is connected to the electrical circuit of the device for overvoltage protection according to the invention.

[0025] The cavity 50 between the casing 5 and the varistor 4 is hermetically separated from the surrounding environment and the electrical elements of the device for overvoltage protection are cast in the housing 1 with an insulating casting material 2.

[0026] In the illustrated example of embodiment, the casing 5 lies by a part of its side walls 52 on the upper surface of the varistor 4 and only by one side wall 52 it overlaps the ground plan outline of the varistor 4, which enables to introduce the disconnected sections of the electrical circuit into the cavity 50 between the varistor 4 and the casing 5 and to realize a sufficiently efficient and resistant thermal disconnecting device in the cavity 50. The thermal disconnecting device consists of the end portion 8b of a phase conductor 8, a second lead 4f of the varistor 4, a draw spring 9 and a solder with a set melting temperature. The side wall 52 of the casing 5, which is arranged outside the ground plan outline of the varistor 4, i.e. the wall which overlaps the ground plan outline of the varistor 4 is longer than the other side walls 52 of the casing 5. This longer side wall 52 extends in the part where it is arranged outside the ground plan outline of the varistor 4 below the level of the upper surface of the varistor 4, as is shown in Fig. 1.

[0027] The process of casting with the insulating casting material is performed in two stages, when before the first stage of casting all the components of the device for overvoltage protection are assembled into a functional whole, which is placed in a housing 1. For the purpose of a suitable arrangement of the elements of the system for casting, the varistor 4 is mounted on a pad 11, which is mounted on the bottom of the housing 1. In an unillustrated example of embodiment, casting is performed without a pad 11. A casing 5 is mounted on the varistor 4, all the elements being assembled into a functional whole. In the first stage of casting the insulating casting material is cast to a height slightly above the level of the upper surface of the varistor 4, by which means all the cavities in the housing 1 are filled and the insulating casting material seals the lines of contact of the side walls of the housing 5 and the upper surface of the varistor 4. At the same time, however, the casting material due to the balance of the hydrostatic pressure of the casting material and the pressure of the air in the cavity 50, does not penetrate into the cavity 50 and still seals the space beween the longer side wall 52 of the casing and the varistor 4. After hardening the insulating casting material after the first stage of casting, the second stage of casting is carried out, when all the remaining conductive parts of device are completely cast with the insulating casting material and, if necessary, also the bottom part of the side walls 52 of the casing 5. Preferably, the second stage of casting is performed up to a height 3 at the level of the upper surface 51 of the casing 5.

[0028] If the casing 5 at least partially made of a translucent and/or transparent material, e.g. from plastics, it enables visual control of the arrangement of the elements in the cavity 50 of the casing 5 and, where appropriate, also visual control of the state of the device after being cast with the insulating casting material 2 up to a part of the height or the whole height of the side walls 52 of the casing 5. For this reason it is advantageous when the upper surface 51 of the casing 52 is arranged at the highest level of all the elements of the device according to the invention, as is apparent from Fig. 1.

[0029] In an unillustrated example of embodiment, the whole casing 5 is cast with the insulating casting material 2 and visual control of the arrangement of the elements in the cavity 50 of the casing 5 is impossible.

[0030] In the example of embodiment shown na Fig. 1 to 3 and 8, the elements of the thermal disconnecting device are arranged in such a manner that the disconnecting movement of the end portion 8b of the phase conductor 8, i.e. the direction of the movement of the disconnected uninsulated end 8a of the phase conductor 8 from the second lead 4f of the varistor 4 is in a plane parallel to the upper surface of the varistor 4. Adapted to this direction of disconnecting is the shape and dimensions of the casing 5, which is also arranged in a plane parallel to the upper surface of the varistor 4. In the embodiments illustrated in Fig. 5 to 7, the disconnecting movement of the end portion 8b of the phase conductor 8, i.e. the direction of movement of the uninsulated end 8a of the phase conductor 8 being disconnected from the second lead 4f of the varistor 4 is situated in a plane inclined or perpendicular to the upper surface of the varistor 4, whereby the shape and dimensions of the casing 5 are adapted to the inclined or perpendicular direction of the disconnecting movement. The cavity 50 is then arranged inclined direction or perpendicular, etc., to the side wall of the varistor 4. In the case of inclined or perpendicular disconnecting movement of the phase conductor 8 in relation to the plane of the varistor 4 it is advantageous if the second lead 4f of the varistor 4 is bent with its surface perpendicularly towards this direction, i.e. it is situated in a direction inclined to the plane of the varistor 4 or it is situated in a plane parallel to that of the varistor 4.

[0031] In principle, the casing 5 and the side wall of the varistor 4 constitute an enclosed cavity 50, filled by air, for accommodating a properly sized thermal disconnecting device, which endures high impulse loads, to which the device according to the invention is exposed when protecting LED street lighting and other electrical circuits with a very high loading. At the same time, using a sealed casing 5 enables to reach high ingress protection IP 65 or IP 66 and higher.

[0032] The device according to the invention operates in such a manner that during the heating of the varistor 4, heat is propagated from the body 4a of the varistor 4 via the electrode 4b to the second lead 4f of the varistor 4. When the second lead 4f is heated to the set temperature of melting, the solder connecting the uninsulated end 8a of the phase conductor 8 and the second lead 4f of the varistor 4 is melted and the draw spring 9 deflects the end portion 8b of the phase conductor 8 with the uninsulated end 8a away from the second lead 4f of the varistor 4. Thus the varistor 4 is automatically disconnected from the protected circuit before a short circuit of the varistor 4. The disconnection of the varistor 4 is in case of need locally or remotely signalled, e.g. in the illustrated example of embodiment by means of a signalling device 14.

[0033] The device according to the invention and the method of producing it allows to use any varistor 4 of any ground plan shape or also any cross-section shape, including high-performance varistors of relatively large dimensions, and including blocks of parallel interconnected varistor units which not only have a ground plan of a square shape, as illustrated, but substantially of any shape and size. The casing 5 can be made in any shape, size, etc., which corresponds to the used varistor 4 or the blocks of parallel-connected varistor units.

Claims

1. A device for overvoltage protection with high ingress protection, particularly for the protection of LED street lighting, comprising a varistor (4), which is by each of its leads (4d, 4f) connected to a protected electrical circuit, whereby at one lead (4f) is soldered by solder with a set temperature of melting an uninsulated end (8a) of an electrical conductor (8), with which is aligned a spring (9) for deflecting the uninsulated end (8a) of the electrical conductor (8) away from the lead (4f) of the varistor (4) after melting the solder, characterized in that the end portion (8b) of the electrical conductor (8) with the uninsulated end (8a), the lead (4f) of the varistor (4), their soldered connection with an adjustable temperature of melting and the spring (9) are arranged in a cavity (50), which is separated in an airtight manner from the surrounding environment, whereby the other elements of the device are also separated in an airtight manner from the surrounding environment.

2. The device according to claim 1, characterized in that the cavity (50) is formed between a casing (5) and a sidel wall of the varistor (4), whereby the side walls of the casing (5) are along the entire circumference of the casing (5) at least on a part of its height cast by an insulating casting material (2) and the other elements of the device are completely cast with the insulating casting material (2).

3. The device according to claim 1 or 2, characterized in that the electrical conductor with an uninsulated end (8a) is composed of a copper cable.

4. The device according to claim 1 or 2, characterized in that the electrical conductor with an uninsulated end (8a) is composed of a copper wire.

5. The device according to claim 1 or 2, characterized in that the electrical conductor with an uninsulated end (8a) is composed of a copper strip.

6. The device according to any of claims 1 to 5, characterized in that the cavity (50) is situated along the side wall of the varistor (4) or transversely to the side wall of the varistor (4) or perpendicularly to the side wall of the varistor (4).

7. The device according to claim 2, characterized in that the casing (5) is at least partially made of translucent and/or transparent material.

8. The device according to any of claims 1 to 7, characterized in that the varistor (4) is composed of a block of at least varistor units connected in parallel.

9. A method of production of a device for overvoltage protection with high ingress protection, particularly for the protection of LED street lighting comprising a varistor (4), which is by each of its leads (4d, 4f) connected to a protected electrical circuit, whereby at one lead (4f) is soldered by solder with a set temperature of melting an uninsulated end (8a) of an electrical conductor (8), with which a spring (9) is aligned for deflecting the uninsulated end (8a) of the electrical conductor (8) away from the lead (4f) of the varistor (4) after melting the solder, characterized in that the device is cast with an insulating casting material (2) in two stages, whereby before the first stage of casting all the parts of the device for overvoltage protection are assembled into a functional whole, which is placed in a housing (1), whereupon the first stage of casting is carried out, during which the insulating casting material is cast to a height slightly above the upper surface of the varistor (4), by which means all the cavities in the housing are filled (1), except the cavity (50) of the casing (5) and after hardening of the insulating casting material from the first stage of casting, the second stage of casting is carried out, when all the remaining electrically conductive parts of the device are cast with the casting material, including at least the bottom part of the side walls (52) of the casing (5).

10. The method according to claim 9, characterized in that the second stage of casting is performed up to a height (3) at the level of the upper surface (51) of the casing (5).

11. The method according to claim 9 or 10, characterized in that before casting, the varistor (4) is mounted on a pad (11), which is mounted on the bottom of the housing (1).

Drawing