Patent Description:
Modern day electrical grids have to ensure distribution of electrical energy to users and also ensure communication between electrical devices via electrical grid (wires). Communication is often disturbed due to conductive interference caused by different electrical devices used at user location; therefore electrical grids have to incorporate filtering electronic devices for reducing disturbances in the frequency band used for communication.

Due to frequent use of modern measuring systems in the low-voltage electrical grids, where smart electricity meters communicate via the same electrical conductors as is used for distribution of electrical energy to users, the electrical grids require more and more filtering devices. Each filtering device has to be connected in the electrical grid in a way which requires a physical interruption of electrical energy, connection of conductors into the filtering device and out of it as well as re-connection of electrical energy. These are actions, which may be dangerous to the staff and/or can cause huge damage (in case of a fire, for example), different standards and rules define requirements for safe work, connection and operation of electrical devices in electrical grids.

Safety requirements for operation of electronic devices in low-voltage electrical grids in the EU are defined in the Directive <NUM>/<NUM>/EU, which has been used since <NUM>. In particular, the general and safety requirements for connecting filtering electronic devices into electrical grids are defined in standards EN <NUM>-<NUM>-<NUM> and EN <NUM>-<NUM>-<NUM>, published on <NUM>. Standard EN <NUM>-<NUM>-<NUM>:<NUM> is for signals on low-voltage electrical installations in the frequency band <NUM> to <NUM>,<NUM>, while the part <NUM>-<NUM> is for low-voltage decoupling filters - general specification. Standard EN <NUM>-<NUM>-<NUM>:<NUM> is for signals on low-voltage electrical installations in the frequency band <NUM> to <NUM>,<NUM> and <NUM>,<NUM> to <NUM>, while the part <NUM>-<NUM> is for low voltage decoupling filters - safety requirements.

PLC filters are intended for reducing unwanted conductive disturbances in AMI-PLC systems under <NUM> as well as up to <NUM> for remote reading of smart electricity meters require a constructional solution of a housing with a terminal block for simple and reliable connection to the electrical grid.

The technical problem, which is solved by the present invention, is construction of the housing of a filtering electronic device to be connected in the electrical grid circuit, wherein the said housing will ensure easy and reliable electrical and mechanical connections between the electronic circuit and interrupted conductors of the electrical grid. The constructional design of the housing for safe installation and reliable connection of an electronic device, preferably PLC filter and similar devices should enable connection into one-phase or three-phase network, depending on the type of network into which the device will be connected. Input and output clips of devices have to enable electrical, mechanical and functional reliability in agreement with standards for such devices.

The geometry of the arrangement of connective clips and safety barriers in the terminal block has to enable suitable insulation and creepage distances as defined in the said standards, while at the same time the arrangement should ensure minimum dimensions of the housing and the terminal block for connection into conductors of one-phase or three-phase networks.

The housing construction has to enable good heat dissipation due to large circuit loads, but at the same time it has to ensure high electrical breakthrough strength at possible voltage surges in the electrical grids.

Different housings for electrical and electronic devices are known, but they differ from the present invention in their shape and their connection points. The closest known solution is the housing of the applicant, which has a slightly rounded outer shape and differently arranged connectors and intermediate barriers/walls.

The housing of one of the manufacturers of filtering devices is shaped so that the bottom part is a rectangular prism with a second smaller rectangular prism on it. At the side of the bottom prism openings for connective wires are provided, wherein the wires may be attached from above once the cover is opened. The shape of the housing and the connectors differs from the present invention.

Other manufacturers of similar filtering devices do not have similar solutions to the present invention, not in the market nor in patent databases.

Patent <CIT> relates to a terminal device, which includes a first cover portion to be positioned above the first screw terminals, wherein the first cover portion including the first operation openings which respectively expose screws of the first screw terminals, a second cover portion to be positioned above the second screw terminals, the second cover portion including the second operation openings which respectively expose screws of the second screw terminals. And the terminal device further includes a connecting portion connecting the first cover portion with the second cover portion and including wire insertion holes through which electric wires connected to the first screw terminals respectively pass and wire insertion paths which communicate with the wire insertion holes and through which the electric wires respectively pass, each insertion path being provided on an upper surface of the second cover portion between two adjacent second operation openings.

Patent application <CIT> describes a terminal block insert that comprises a steel frame of rectangular cross-section, formed from sheet metal, and a strip of brass secured to the frame by interlocking tabs and notches. The frame has transverse threaded bores each for receiving a respective screw.

Patent application <CIT> discloses an adapter for connecting the ends of conductors to a terminal, e.g., a terminal of a socket outlet, batten lamp holder or switch, and comprises a metal block having a through bore for receiving the conductor ends with two independent spaced means for securing them therein, and a spigot for making a connection with a bore in the terminal. The rectangular brass block has two pinch screws each of which secures the ends of two aluminium conductors within the throughbore and the spigot extends parallel to and coplanar with the screws. The embodiment shown has a second throughbore with pinch screws for receiving a spur conductor. The spigot may be integral with the block or screw-threadedly attached thereto.

Patent application <CIT> discloses a connector for a terminal block for adjoining a pair of wires for providing electrical conduction between the wires is disclosed. The connector has a cylindrical body having one screw hole near each end of the body and a wire end plate formed internally to and at substantially the longitudinal center of the body for limiting wire insertion. A conduction plate is inserted into the hollow space of the cylindrical body and has a length substantially the same as that of the cylindrical body along the longitudinal direction thereof. The conduction plate has a concaved surface conforming to the generally spherical cross section of the wires for partially enclosing the wires when inserted for adjoining. The concaved surface provides low electrical resistance between the adjoined wires when two screws mating with the screw holes are installed and each driven firmly onto the corresponding one of the adjoining wires thereby squeezing the wires firmly onto the conduction plate.

<CIT> discloses a terminal block with a configuration which differs significantly from the present invention.

Patent application <CIT> discloses a lower-step terminal cover, provided with a pair of leg parts extending from each side in its movement direction, which is retained by the terminal board in free sliding movement by being inserted into a terminal insertion hole, and is free to move in the same plane with a terminal releasing face. As the lower-step terminal cover is moved, the terminal releasing face of the lower-step terminal board part is put out in a space between both leg parts to connect a connecting terminal with the counterpart terminal. Patent application <CIT> is an upgrade of the solution presented in document <CIT> and aims to provide a solution for a terminal block that prevents fire due to heat generation resulting from poor contacts. Upon connection of a plurality of input/output terminals for connecting a power source are installed with a terminal block, a heat reaction type foam material is installed opposite to the input/output terminals on a foam material installation section of a terminal attachment base. A poor contact is cancelled by expanding a volume of the foam material, when temperature reaches a predetermined temperature.

The essence of the housing with the terminal block according to the invention is that it comprises:.

The filter device or any other electronic device that needs to be connected to the electrical grid can be installed in the tubular housing. The terminal block comprises the socket outlet box, the upper portion of the socket outlet box with a cover, connection terminals and associated screws. The socket outlet box allows installation of connection terminals, which ensure fixing of the connecting wires of the filter device or any other electronic device with at least one screw on one side and the fixing of external electrical grid conductors with at least one, preferably two screws for better contact on the other side. Namely, the screws must securely fasten the connecting wires of the device and the electrical grid connecting wires (conductors), which is achieved by the prescribed screwing force or by doubling the screws, otherwise poor connections can occur, which can cause cracking, heating or even fire, since the common current of an individual customer-consumer or the entire flat, house or industrial facility flows through the metal connection terminals. Access to the screws is provided through the upper portion of the socket outlet box, and, to provide safety, the cover covers the screws in the threaded holes (to prevent contact and unscrewing of screws when voltage is applied) for attaching the connection cables to the electrical grid. The housing of the socket outlet box and the cover can be additionally equipped with an additional ring or a sealing screw for installing a seal, which prevents unauthorized opening of the cover on the socket outlet box.

The tubular housing with the filter or any other device arranged thereon and connected to the socket outlet box can be completely or partially sealed with a suitable material, preferably epoxy resin, which inseparably joins all said elements. Sealing with epoxy resin significantly improves the life span of the product, as it becomes a monolithic block, which cannot be penetrated by moisture and various particles that could impair the insulating properties. In addition, the elements sealed in the mass cannot move, therefore the degree of insulation is increased because the epoxy mass is a higher dielectric than air and the thermal conductivity is also improved, so the heat is dissipated faster through the mass outwards to the housing and the environment. This consequently means that the MTBF (mean time between failures) time is improved, i.e. the time elapsed between product failures or a measure of the reliability of a product or component. Similarly, before being installed in the tubular housing, the filter device can be surrounded by additional insulating plates in the form of a square, which can meet additional safety requirements for reinforced or double insulation of the device, which must be specifically marked on the device and properly checked in compliance with standards EN <NUM>-<NUM>-<NUM> and EN <NUM>-<NUM>-<NUM>.

The metal connection terminal has any elongated shape, wherein the preferred shape is an elongated cuboid with square or rectangular side faces, wherein the said cuboid is provided with a round borehole along the horizontal axis. Perpendicularly to the longitudinal axis of the metal connection terminal at least one first threaded hole is provided on one side and at least one, preferably two second threaded holes, are provided on the other side. The metal connection terminals are separated from each other by partitions which are dimensioned in such a way as to increase the electrical breakdown strength and the creep distance between the metal connection terminals. The thicknesses of seats and partitions must meet the requirements for the material of the terminal block to achieve electrical breakdown strength, according to the safety category to be achieved with the device, and must also be properly checked in accordance with the recommendation of the Directive and standard EN <NUM>-<NUM>-<NUM> and EN <NUM>- <NUM>-<NUM>. The plastic materials used to make the components of the terminal block and the material used to seal the interior of the housing with the terminal block, which is usually an appropriate epoxy resin, must have good mechanical and electrical (insulating) properties, good heat dissipation and must also meet corresponding flammability standards in accordance with UL <NUM> or Glow Wire Flammability standards.

The material for manufacturing a terminal block is preferably a polycarbonate, to which about <NUM>% of glass fibres have been added for reinforcement.

In case earthing of the metal housing is required for safety reasons or to prevent electromagnetic interference, this may be achieved by an additional connector on the terminal block or by a separate earthing conductor attached to the metal housing.

The housing according to the invention allows reliable connection of the electronic device to the electrical grid circuit, where the currents exceed <NUM> A, or even exceed <NUM> A, so it is desirable that the current flows from the device to the connecting cables and back with smallest possible resistance. Therefore, the metal connection terminals proposed in the invention are square or rectangular in cross-section with a longitudinal bore having a diameter exceeding the diameters of the connection conductors, dimensioned for an individual current load determined by a fuse or protective element in the electrical grid. The metal connection terminals are made of well-conducting materials, such as copper or brass. To increase corrosion resistance due to the climatic influences of the environment, the connection terminals are preferably nickel-plated or tinned.

The housing according to the invention is also suitable for measuring, coupling, blocking, transceiving, protective and other devices. If the devices are intended for single-phase or multi-phase electrical grids, the terminal block is narrower or wider, so it is adaptable to the required number of connectors, in general for each phase <NUM> connectors for input and output of a phase conductor and additionally <NUM> connector for the neutral conductor. This means <NUM> connectors for a single-phase device and <NUM> connectors for a three-phase device. For some types of devices, it is also necessary to split the neutral conductor to the inlet and outlet of the neutral conductor, which means <NUM> connectors for a single-phase device and <NUM> connectors for a three-phase device. Some types of electronic devices (measuring, blocking) would only require two connectors, for a single-phase connection of a phase and neutral conductor and four connectors for three-phase conductors and a neutral conductor.

The present solution allows connection of devices to the electrical grid downstream of electricity meters with existing protective elements (fuses), which ensures safe operation by observing the prescribed dimensions of conductor diameters, mutual distances, partition wall thickness for allowable current loads and rated currents of individual filter devices. Protective elements such as fuses, arresters and the like can also be arranged in the housing of a filter device with a terminal block or other electronic device.

Standards EN <NUM>-<NUM>-<NUM>: <NUM> and EN <NUM>-<NUM>-<NUM>: <NUM> for filter and other electronic devices have been taken into account during design of the housing for the filter device with the terminal block for direct connection to the electrical grid, while for all materials used, the applicable restrictions for marketing or use of certain hazardous substances and preparations or RoHS regulations have also been taken into account. This is also included in manuals with tables for dimensioning conductors, permissible current loads for copper conductors with PVC insulation, rated currents of fuses, correlation factors and conditions for dimensioning rated current and other parameters.

The invention allows connection of a filter device or any other device to the electrical grid without or with a fuse. The housing according to the invention enables reliable electrical and mechanical connections between the electronic circuit and interrupted electrical grid conductors.

The housing for a filtering device with the terminal block for connecting into an electrical grid according to the invention will be described in further detail based on exemplary embodiments and figures, which show:.

A possible embodiment of the housing with the terminal block for connecting a filter device to the electrical grid as shown in <FIG> is based on the construction of a socket outlet box <NUM> that separates the filter device <NUM> with a vertical dividing wall <NUM>, wherein the filter device has to be connected without an additional fuse to the electrical grid, and the terminal block, with which the filter device <NUM> can be connected to the electrical grid. The terminal block consists of the socket outlet box <NUM>, an upper portion <NUM> of the socket outlet box <NUM> with a cover <NUM>, a metal connection terminal <NUM> and the associated screws <NUM> and <NUM>. The cover <NUM> is pivotally attached to the upper portion <NUM> via two levers 24c, which are fastened to the upper portion <NUM> with an axle 24d.

As shown in <FIG>, the housing according to the embodiment includes the socket outlet box <NUM>, openings <NUM> in the vertical dividing wall <NUM> and horizontal seats with partitions <NUM>, which allow arrangement of any metal connection terminals <NUM>. The metal connection terminal <NUM> has any elongated shape, preferably an elongated cuboid with side faces of square or rectangular shape having a round hole <NUM> provided along the horizontal axis. One first threaded hole <NUM> and two second threaded holes <NUM> are provided perpendicularly to the longitudinal axis of the metal connection terminal <NUM>. When connectors <NUM> of the filter device <NUM> are pushed through the openings <NUM> of the dividing wall <NUM> into a pipe <NUM> of the metal connection terminal <NUM> from the dividing wall <NUM> side, the connecting wires <NUM> are fastened to the metal connection terminals <NUM> by means of screws <NUM> through the threaded opening <NUM> (see <FIG>). Instead of screws <NUM>, the connecting wires <NUM> can be fastened to the metal connection terminal <NUM> by welding, where the principle of fusion welding with electricity can be applied.

The upper portion <NUM> of the socket outlet box <NUM> is shaped so that it is attached to the socket outlet box <NUM> with an edge <NUM>, wherein the screws <NUM> screwed into the threaded holes <NUM> on the connection terminals <NUM> engage the openings <NUM> on the upper portion <NUM> of the socket outlet box <NUM>, the screws <NUM> being screwed through said holes into the threaded openings <NUM> on the metal connection terminals <NUM> that allow the attachment of external connection conductors <NUM> into openings <NUM> on the front side of the terminal block so as to ensure the connection of the filter device <NUM> to the electrical grid. Also, semi-circular protrusions <NUM> of the socket outlet box <NUM> match semi-circular protrusions <NUM> of the upper portion <NUM> of the socket outlet box <NUM> so that together they form the openings <NUM>, the diameter of which exactly fits the diameters of the openings of the round tubes <NUM> in the metal connection terminals <NUM>. A cover <NUM> is arranged on the upper portion <NUM>, which covers the openings <NUM> and covers the screws for attaching the connecting conductors to the electrical grid, in order to prevent contact and unscrewing of the screws when voltage is applied. The upper portion <NUM> of the socket outlet box <NUM> and the cover <NUM> can be equipped with an additional ring 24a or a sealing screw for installing a seal, which prevents unauthorized opening of the cover on the socket outlet box 1a.

The procedure for connecting a filter device to an electrical grid with the housing with the terminal block includes the following. The connecting wires <NUM> of the filter device <NUM> are attached to the metal connection terminals <NUM> by being pushed through the designated openings <NUM> in the dividing wall <NUM> of the socket outlet box <NUM> and tightened with screws <NUM>. A tubular housing <NUM> is pulled over the filter device <NUM> and attached to a frame <NUM> of the socket outlet box <NUM>, from the other side, it can be sealed with an appropriate epoxy resin or closed with a cover <NUM>. The epoxy resin can be poured only partially in order to cover the connecting wires <NUM> and connect the tubular housing <NUM> with the socket outlet box <NUM>. In this case, the filter device remains unsealed and the tubular housing <NUM> must be closed with the cover <NUM>. In case the epoxy resin is poured to the top of the tubular housing <NUM>, the filter device is completely sealed and the cover <NUM> is not needed. After attaching all the connecting wires <NUM> of the filter device <NUM> to the metal connection terminals <NUM> with screws <NUM>, the upper portion <NUM> of the socket outlet box <NUM> is mounted onto the socket outlet box <NUM>. The upper part <NUM> of the socket outlet box <NUM> with the first ring 24a is provided with a cover <NUM> with a second ring 24b. A security seal tape is arranged through the first and second rings. Thus, the filter device <NUM> in the housing <NUM> with the connection socket is ready for being connected to the electrical grid, since the upper portion <NUM> allows the connection of the housing with the filter device and the terminal block to the electrical grid with at least one screw <NUM> per connection cable, preferably with two, which allows easy and reliable fastening of external connection conductors <NUM> of the electrical grid. The upper portion <NUM> must be mounted onto the socket outlet box <NUM> before the electrical grid connection cables are connected to the terminal block.

The connection to the electrical grid is achieved so that the first connecting wire <NUM> is inserted into a first channel <NUM> of the first connection terminal <NUM> and fastened with the first screw <NUM> through the first threaded opening <NUM>. On the other side of the first connection terminal <NUM>, an input connection cable L of the electrical grid is inserted into the first channel <NUM> through the first opening <NUM> of the terminal block and fastened with the first screw <NUM> (see <FIG>). The second connecting wire <NUM> is inserted into a second channel <NUM> of the second connection terminal <NUM> and fastened with a second screw <NUM> through the second threaded opening <NUM>. On the other side of the second connection terminal <NUM>, an input connection cable L* of the electrical grid is inserted into the second channel <NUM> through the second opening <NUM> of the terminal block and fastened with the second screw <NUM>. The third connecting wire <NUM> is inserted into a third channel <NUM> of the third connection terminal <NUM> and fastened with a third screw <NUM> through the third threaded opening <NUM>. On the other side of the third connection terminal <NUM>, a neutral connection cable N of the electrical grid is inserted into the third channel <NUM> through the second opening <NUM> of the terminal block and fastened with the third screw <NUM>. The conductors L, L* and N of the single-phase electrical grid are inserted into the terminal blocks and fastened with a screw <NUM>, which are accessible for fastening (screwing) from the outside of the housing with the terminal block.

The connection of the device <NUM> with the connecting wires <NUM> with screws <NUM> or of the connecting wires <NUM> to the electrical grid with screws <NUM> can be done with one screw per single metal connection terminal or with two screws to increase the reliability of the joints. The screws <NUM> and <NUM> used can have different notches (straight, cross, hex, etc.) to increase the screwing force or to prevent unauthorized access to the connections of the device and electrical grid power lines, as screws with special notches require specially adapted screwdrivers. In the embodiment for a single-phase network shown in <FIG>, the connection conductors <NUM> are marked as L, L* and N.

Claim 1:
A housing for a filtering device (<NUM>) with a terminal block for connecting into an electrical grid, wherein the said terminal block comprises:
- a socket outlet box (<NUM>) with at least two horizontal seats (<NUM>) with partitions and a vertical dividing wall (<NUM>) with openings (<NUM>) at one end of the seats (<NUM>), the openings (<NUM>) being adapted to receive connecting wires (<NUM>) of a filtering device (<NUM>) or any other electronic device,
- at least two connection terminals (<NUM>), which are mounted in the horizontal seats (<NUM>) of the socket outlet box (<NUM>), each of the connection terminals (<NUM>) being provided with a longitudinal borehole (<NUM>) and with at least two perpendicular threaded holes (<NUM>, <NUM>), one each end of each connection terminal (<NUM>), the threaded hole (<NUM>) on the filtering device (<NUM>) end is provided with a screw (<NUM>) for fastening a connecting wire (<NUM>) from the filtering device (<NUM>), while the threaded hole (<NUM>) on the other end of the connection terminal (<NUM>) is provided with a screw (<NUM>) for fastening an electrical grid conductor (<NUM>),
- an upper portion (<NUM>) of the terminal block is attached to the socket outlet box (<NUM>) and formed so as to cover the horizontal seats (<NUM>) and the connection terminals (<NUM>), so that the screws (<NUM>) for fixing the electrical grid conductors (<NUM>) are accessible from the outside of the terminal block via openings (<NUM>) and the upper portion (<NUM>) is shaped such that together with the socket outlet box (<NUM>) it forms openings (<NUM>) for the electrical grid conductors (<NUM>) to be inserted, wherein the openings (<NUM>) are accessible from the outside of the terminal block,
characterized in that a cover (<NUM>) is provided on the upper part (<NUM>) of the terminal block through which the screws (<NUM>) of the connection terminals (<NUM>) are accessible via openings (<NUM>),
wherein said cover (<NUM>) is configured to cover the openings (<NUM>) and the screws (<NUM>) in the threaded holes (<NUM>) in order to prevent contact and unscrewing of the screws (<NUM>) when voltage is applied.