Claims:We claim:
1. An electrical enclosure assembly (200) housing an electrical device, made up of metal, the electrical enclosure assembly (200) comprising:
a housing box (110) coated with a non conducting material, open at one side and having at least one hinge component (140) welded thereon, the hinge component (140) having a cylindrical slot therein;
a shield plate (130) removably covering the housing box (110), and
a door (120) coated with a non conducting material and having at least one hinge pin (150) welded thereon, the hinge pin (150) having a knurl profile thereon, wherein the door (120) is removably attached to the housing box (110) by inserting the hinge pin (150) into the cylindrical slot of the hinge component (140) on the housing box (110);
wherein the friction between the hinge pin (150) and the hinge component (140) during opening and closing of the door (120) peels off the non-conducting material from inside the hinge component (140) to establish an electrical contact between the housing box (110) and the door (120) to maintain continuous earthing of the electrical enclosure assembly (200).
2. An electrical enclosure assembly (200) as claimed in claim 1, wherein the hinge pin (150) and the hinge component (140) are made up of electrically conductive material to establish an electrical contact between the housing (110) and the door (120) to maintain continuous earthing of the electrical enclosure assembly (200).
, Description:Field of the invention:
The invention relates generally to, electrical enclosure, more particularly it relates to earthing arrangement for the electrical enclosure door.
Background of the invention:
Electrical enclosures for housing electrical or electronic devices such as switchgears, power distribution box etc, are typically made up of metal and include a front open housing, a removable shield for the housing and a door. Earthing is provided in these electrical enclosures to minimize the risk of receiving an electric shock if metal parts are touched, when a fault is present. To avoid this, non-current carrying metal parts of the electrical system are connected to the general mass of earth by means of an earthing system comprising of earth conductors to conduct the fault currents safely to the ground. Present practice of providing earthing in distribution box is via a wire connection between door and shield. As per this practice there is no way by which earthing will be maintained throughout the system once the shield is removed. For conducting any maintenance, it is a common practice to remove the shield or sometimes door at site and then in most of the cases wire never placed back, leading to loss of earthing protection. Referring to figure 1, an electrical enclosure assembly (100) in accordance with the existing art is shown, wherein the housing (10) is fitted with a removable shield (30) and a door (20). In this system, earthing is achieved by using a wire (40) which is assembled with the housing box earthing or removable shield (30). In both these cases if door (20) or removable shield (30) is removed there is a chance of not placing wire (40) back on earth point. Therefore to avert this threat or to make door earthing full proof, door wire needs to be eliminated from system.
The patent GB2154079 discloses a device for making an earth connection between an electrical enclosure (18) and a cable termination received by the enclosure. The prior art does not ensure the person will not get shock and earthing will be ensured even if shield (inner plate) is removed / not there. In another product - earth bonding hinges, the electrical connection is made by a separate flat multilam contact strip. The product does not provide the economic solution to the problem.
Accordingly, there exists a need to provide safety in the form of proper earthing to the human personnel during maintenance/ operation. The present invention overcomes above mentioned drawbacks in the prior art.
Objects of the invention:
An object of the present invention is to provide an earthing arrangement for an electrical enclosure.
Another object of the present invention is to provide an earthing arrangement for an electrical enclosure, even when its shield is removed and not placed back.
Yet another object of the present invention is to provide safety in the form of proper earthing and provide safety to the human personnel during maintenance or operation of the electrical enclosure.
Still another object of the present invention is to provide a continuous and reliable earthing arrangement for an electrical enclosure.
Summary of the invention:
The present invention provides an electrical enclosure assembly to ensure a reliable earthing and provide safety to the human personnel during maintenance or operation of the electrical enclosure. A hinge is provided for attaching door to the electrical device housing, which ensures earthing continuity even when shield is removed or the shield is not in place. Thus, even if the shielding plate providing earthing to the enclosure is removed and not placed back during maintenance or other operations of the electrical equipment inside, the electrical continuity and in turn , earthing of the enclosure is maintained.
Brief description of the drawings:
Figure 1 shows a perspective view of electrical enclosure (100) in open condition in accordance with the existing art.
Figure 2 shows a perspective view of electrical enclosure (200) in open condition with a detailed view of hinge, in accordance with the present invention.
Figure 3 shows exploded view of electrical enclosure (200) in open condition, in accordance with the present invention.
Figure 4 shows a detailed view of hinge for the electrical enclosure (200) in accordance with the present invention.
Detailed description of the embodiments:
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
In one aspect, the present invention provides an electrical enclosure assembly to ensure a reliable earthing and provide safety to the human personnel during maintenance or operation of the electrical enclosure. The electrical enclosure is coated with a non conducting material. The electrical enclosure comprises of a housing box open at one side and housing the electrical device inside, a removable shield for the housing box, a removable door and hinge components welded on the door and the housing box for removably attaching the door to the housing box. Hinge component or hinge pin welded on the door is having a knurl profile and the cylindrical hinge component welded on the housing box is having a cylindrical slot therein. Door is attached to the housing box by inserting the hinge pin on the door into hinge component of the housing box. When the hinge pin is having knurl profile, it peels off the non conducting coating from inside the cylindrical hinge on the housing box, during opening and closing movements of the door. Thus, the metal to metal contact is established for earthing. In an embodiment, the hinge components can be made of the conducting metal to maintain continuous earthing of the electrical enclosure assembly.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.
Referring to figures 2, 3 and 4, a detailed view of an electrical enclosure assembly (200) in accordance with the present invention is shown. The electrical enclosure assembly (200) houses the electrical or electronic devices such as switches, power distribution box, knobs, etc. The electrical enclosure assembly (200) comprises of a housing box (110), a removable shield cover (130) and a removable door (120). The housing box (110) is open from one side and having at least one hinge component (140) having a cylindrical slot therein, welded thereon. The shield plate (130) removably covers the housing box (110). The door (120) is configured with at least one hinge pin (150) welded thereon. The hinge pin (150) is having a knurl profile thereon. The door (120) can be removably attached to the housing (110) by inserting the hinge pin (150) into the cylindrical slot of the hinge component (140) on the housing (110).
In an embodiment, the friction between the hinge pin (150) having knurl profile thereon and the hinge component (140) during opening and closing of the door (120) peels off the non-conducting material from inside the hinge component (140) and establishes an electrical contact between the housing (110) and the door (120) to maintain continuous earthing of the electrical enclosure assembly (200).
In another embodiment, the hinge pin (150) and the hinge component (140) are made up of electrically conductive material to establish an electrical contact between the housing (110) and the door (120) to maintain continuous earthing of the electrical enclosure assembly (200).
Advantages of the invention:
• The electrical enclosure assembly (200) of the present invention provides a continuous and reliable earthing arrangement and provides safety to the human personnel during electrical operations.
• The electrical enclosure assembly (200) of the present invention provides a foolproof earthing to the enclosure door without the need of arranging any additional component for earthing arrangement.
• The electrical enclosure assembly (200) of the present invention provides an earthing arrangement even when its shield (130) is removed and not placed back.
• The electrical enclosure assembly (200) of the present invention provides an economic solution to the problem of providing continuous and reliable earthing to the electrical enclosures.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.