JP7460304B2 - Electrical box grounding structure - Google Patents

Description

The present invention relates to a grounding structure for an electrical equipment box.

In buildings such as houses, electrical boxes that house electrical components may be installed (see, for example, Patent Document 1). Such electrical boxes are attached, for example, to a wall inside the building, and are configured to include a metal plate member to which electrical components are attached, and a metal cover member that covers the plate member and electrical components. In this case, the plate member is fixed to the wall, and the cover member is removably fixed to a fixture fixed to the wall.

In the electrical box described above, it is common to ground the cover member via an earth wire in case of an electric leakage to the cover member. In this case, the grounding structure can be, for example, a ground terminal block that is grounded to the plate member via a ground path, and the ground terminal block and the cover member are connected via an earth wire.

JP 2012-040796 A

In the above-described configuration in which the grounding terminal block of the plate member and the cover member are connected via the grounding wire, when fixing the cover member to the fixture, first connect the grounding terminal block and the cover member with the grounding wire, and then It is considered that the cover member will be fixed to the fixture in this state. However, in this case, the ground wire restricts how the cover member can be handled, which may make it difficult to fix the cover member. Further, since it is necessary to fix the cover member while paying attention not to pinch the ground wire between the cover member and the plate member, it is considered that the fixing work is difficult in this respect as well.

The present invention was made in consideration of the above circumstances, and its main objective is to provide a grounding structure for an electrical box that can easily fix the cover member to the electrical box when the cover member is grounded.

In order to solve the above problems, a grounding structure for an electrical box according to a first aspect of the present invention is such that an electrical box containing electrical components is attached to a wall in a building, and the electrical box is fixed to the wall, A plate member to which the electric component is attached, a metal fixing part provided on the outer circumferential side of the plate member, and a metal fixing part provided to accommodate the plate member and the fixing part inside; a metal cover member fixed using a fastener, the plate member is provided with a grounding terminal block grounded via a grounding path, and the grounding terminal block and the fixing part are connected to each other. It is characterized by being connected via a ground wire.

According to the first invention, the metal cover member is fixed to the metal fixing part using a fastener, so that the cover member and the fixing part are electrically connected directly or via the fastener. In addition, a ground terminal block grounded via a ground path is provided on the plate member, and the ground terminal block and the fixing part are connected via an earth wire. In this case, since the cover member is electrically connected to the ground terminal block via the fixing part and the earth wire, it is possible to ground the cover member via the ground terminal block. In this configuration, since the ground terminal block and the cover member are not connected via an earth wire, it is possible to avoid inconveniences such as the earth wire restricting the handling of the cover member when fixing the cover member to the fixing part, or the earth wire being pinched between the cover member and the plate member. Therefore, it is possible to easily perform the fixing work of the cover member.

In the grounding structure of the electrical equipment box according to the second invention, in the first invention, both the front and back surfaces of the cover member are painted, and the fastener has a head and a metal shaft. The cover member is fixed to the fixing part by screwing the shaft part into the fixing part through a hole provided in the cover member, and the inner peripheral surface of the hole is not coated. First, the shaft portion is inserted into the hole while being in contact with the inner peripheral surface of the hole.

When an electrical box is installed in a building, the surface of the cover member may be painted for aesthetic reasons. Furthermore, since the cover member is removable, it is conceivable that the back surface of the cover member may be painted in addition to the front surface. In such a case, in a state where the cover member is fixed to the fixed part, a coating film is interposed between the cover member and the fixed part. Therefore, it becomes difficult to directly electrically connect the cover member and the fixed portion due to the insulating properties of the coating film.

Therefore, in the second invention, the inner surface of the hole in the cover member is not painted, and the shaft of the fastener is inserted into the hole while the shaft is in contact with the inner surface of the hole. In this case, even if both the front and back surfaces of the cover member are painted, the cover member and the fixing part can be electrically connected via the shaft. Therefore, even in this configuration, the cover member can be grounded via the fixing part and the ground terminal block.

In the grounding structure of an electrical equipment box according to a third aspect of the invention, in the second aspect, the shaft portion has a tapered portion on a base end side thereof whose diameter is expanded toward the head, and the tapered portion is , the maximum diameter thereof is larger than the diameter of the hole.

According to the third invention, by screwing the shaft of the fastener into the fixed part through the hole of the cover member, the tapered surface of the tapered part collapses the square shape of the opening edge of the hole, and An inclined surface along the tapered surface can be formed. This inclined surface is a part of the inner circumferential surface of the hole, and when the fastener is screwed into the fixed part, the tapered surface of the tapered part comes into surface contact with this inclined surface. Therefore, it is possible to reliably electrically connect the cover member and the fixed part via the shaft part.

FIG. 1 is a diagram showing an overall configuration of a power supply system. FIG. 2 is a front view showing the configuration of a vehicle connection device. FIG. 2 is an exploded perspective view showing the components constituting the housing in an exploded state. FIG. 3 is an enlarged view showing the inside of the frame A in FIG. 2 . FIG. 3 is an enlarged cross-sectional view showing a portion through which a fixing bolt is inserted.

Below, an embodiment of the present invention will be described with reference to the drawings. Figure 1 shows the overall configuration of a power supply system.

As shown in FIG. 1, a power distribution board 11 is provided in a building 10 such as a residence. The distribution board 11 is supplied with AC 100V/200V commercial power sent from a commercial power source (system power source) via a drop-in line 12 . Commercial power supplied to the distribution board 11 is distributed and supplied from the distribution board 11 to a plurality of circuits (branch circuits) within the building 10 . These plurality of circuits include a living circuit 15 that is a living room circuit. The living circuit 15 includes electrical equipment such as a lighting 16, a lighting SW 17, and an outlet 18, and a unit cable 19 connected to these electrical equipment 16-18. The electricity distribution board 11 and the living circuit 15 are connected via a power supply path 22, and commercial power is supplied from the electricity distribution board 11 to the living circuit 15 through the power feeding path 22. Note that in FIG. 1, for convenience, circuits other than the living circuit 15 among the circuits in the building 10 are not shown.

The building 10 is provided with an external power supply system for supplying power from a vehicle 23 as an external power supply device to the living room circuit 15. This makes it possible for the vehicle 23 to supply power to the electrical appliances 16-18 in the living room in the event of a power outage due to a disaster or the like (i.e., when the supply of commercial power is stopped). Note that the circuit capable of supplying power from the vehicle 23 does not necessarily have to be the living room circuit 15, and may be another circuit, such as a bedroom circuit for bedrooms.

The vehicle 23 is, for example, a plug-in hybrid vehicle (PHV) equipped with an on-board battery 24. An outlet 25 is provided inside the vehicle 23. The outlet 25 is electrically connected to the on-board battery 24, and the power stored in the on-board battery 24 can be taken out from the outlet 25. The outlet 25 is an AC 100V outlet, the same as the outlets provided in buildings.

The vehicle 23 can be connected to the building 10 via a power supply cable 27. The power supply cable 27 has a pair of connectors 27a, 27b at both ends, with one connector 27a being connected to the outlet 25 of the vehicle 23 and the other connector 27b being connected to an inlet 31 provided on the outer wall 29 of the building 10. In this connected state, the vehicle 23 (vehicle battery 24) and the inlet 31 are electrically connected via the power supply cable 27.

The building 10 is provided with a connection path 35 that connects the inlet 31 and the power supply path 22. A changeover switch 21 is provided at a connection portion between the connection path 35 and the power supply path 22. The changeover switch 21 is manually operated between a first position where the distribution board 11 and the living circuit 15 are connected and a second position where the inlet 31 (in other words, the connection path 35) and the living circuit 15 are connected. The position can be switched.

When the changeover switch 21 is in the first position, commercial power is supplied from the distribution board 11 to the living circuit 15 via the power supply path 22. The changeover switch 21 is normally set to the first position. On the other hand, when the changeover switch 21 is switched from the first position to the second position with the vehicle 23 (more specifically, the outlet 25) connected to the inlet 31 on the building 10 side via the power supply cable 27, AC 100V power is supplied from the vehicle 23 to the inlet 31 via the power supply cable 27, and the supplied power is supplied from the inlet 31 to the living circuit 15 via the connection path 35 and a part of the power supply path 22.

A vehicle connection device 40 is provided on the connection path 35 that connects the inlet 31 and the changeover switch 21 . The vehicle connection device 40 detects the occurrence of a ground fault or current leakage when power is supplied from the vehicle 23 to the living circuit 15. Below, the configuration of the vehicle connection device 40 will be explained based on FIGS. 2 to 4. FIG. 2 is a front view showing the configuration of the vehicle connection device 40. FIG. 3 is an exploded perspective view showing each member constituting the casing 50 of the vehicle connection device 40 in an exploded state. FIG. 4 is an enlarged view showing the inside of frame A in FIG. 2.

As shown in FIG. 2, the vehicle connection device 40 is attached to a wall surface 37a of a partition wall 37 provided within the building 10. The vehicle connection device 40 includes a housing 50 and a plurality of electrical components 41 to 43 housed in the housing 50. Note that the vehicle connection device 40 corresponds to an electrical equipment box.

The plurality of electrical components 41 to 43 include a ground fault detection section 41, an earth leakage breaker 42, an insulation transformer 43, and the like. The ground fault detection unit 41 detects the occurrence of a ground fault in the power supply cable 27 when power is supplied from the vehicle 23 to the living circuit 15. Further, the earth leakage breaker 42 is for interrupting the electric leakage when electric leakage occurs during power feeding from the vehicle 23 to the living circuit 15.

As shown in FIGS. 2 and 3, the housing section 50 includes a plate member 51 to which each of the electrical components 41 to 43 is attached, and a cover provided to cover the plate member 51 and each of the electrical components 41 to 43. A member 52 and a fixing fitting 53 for fixing the cover member 52 are provided. Note that the fixing metal fitting 53 corresponds to a fixing part.

The plate member 51 is formed into a rectangular shape from steel plate and is fixed to the wall surface 37a of the partition wall 37. The plate member 51 has an attachment surface 51a parallel to the wall surface 37a, and the electrical components 41 to 43 are attached to the attachment surface 51a. The plate member 51 is bent in a step toward the wall surface 37a on both the upper and lower sides of the attachment surface 51a. The vertical plate portion formed by the step bending is a fixed plate portion 51b fixed to the wall surface 37a. The fixed plate portion 51b extends along the upper and lower edges of the plate member 51 and is fixed at multiple points with screws 56.

As shown in FIGS. 2 to 4, the plate member 51 has rectangular notches 54 formed at its four corners (as viewed from the front). Specifically, notches 54 are formed at the four corners of the plate member 51 by removing both ends of each fixing plate portion 51b.

A fixing bracket 53 is provided in each cutout 54. The fixing bracket 53 is formed in an L-shape from a steel plate, and is a so-called L-shaped angle. The fixing bracket 53 has a pair of plate portions 53a, 53b that form a right angle with each other. Of these plate portions 53a, 53b, one plate portion 53a is fixed to the wall surface 37a of the partition wall 37 with a screw 57, and the other plate portion 53b extends from the plate portion 53a to the side opposite the wall surface 37a. The outer surface of the plate portion 53b is arranged facing the opposite side of the plate member 51 in the vertical direction, and is located outside the plate member 51 in the same direction.

The fixing fitting 53 has a rectangular shape when viewed from the front. The fixing metal fittings 53 are arranged such that two sides that are perpendicular to each other when viewed from the front are aligned with two sides that are perpendicular to each other and form the notch portion 54, respectively. As a result, when fixing the fixing bracket 53 to the wall surface 37a with the screws 57, the fixing bracket 53 can be positioned by aligning the two sides of the fixing bracket 53 with the two sides of the notch 54. It is possible.

The cover member 52 is formed of a steel plate into a square box shape. The cover member 52 is open on one side and is provided with the open portion facing the partition wall 37 side. The cover member 52 accommodates the plate member 51, each of the electrical components 41 to 43, and each of the fixing metal fittings 53 inside thereof, and is fixed to each of the fixing metal fittings 53 in the accommodated state.

The cover member 52 is fixed to the plate portion 53b of each fixing fitting 53 with fixing bolts 58. The fixing bolt 58 is a knob bolt that can be turned by hand, and has a knob portion 58a made of resin and a shaft portion 58b made of metal with a threaded groove formed on the outer circumferential surface. Thereby, the cover member 52 is removably fixed to each of the fixing fittings 53. Specifically, the fixing bolt 58 has its shaft portion 58b screwed into a screw hole 62 formed in the plate portion 53b of the fixing fitting 53 through a hole 61 formed in the cover member 52 (see also FIG. 5). ). Note that the fixing bolt 58 corresponds to a fastener, and the knob portion 58a corresponds to a head.

By the way, when a leakage occurs in the vehicle connection device 40, there is a possibility that the leaked current also flows to the cover member 52. Therefore, in this embodiment, the cover member 52 is grounded via a grounding path assuming such a leakage of current to the cover member 52. Therefore, the grounding structure will be explained below.

The front and back surfaces of the cover member 52 are painted with colored paint. Specifically, the entire front and back surfaces of the cover member 52 are coated with colored paint. As a result, coating films are formed on the front and back surfaces of the cover member 52, respectively. Note that this coating film has insulating properties.

On the other hand, the inner peripheral surface of the hole 61 of the cover member 52 is not coated. In other words, the inner peripheral surface of the hole 61 in the cover member 52 is an unpainted surface. Such an unpainted surface can be obtained, for example, by painting the entire surface of the cover member 52 with a colored paint and then processing the holes 61. It can also be obtained by inserting a round rod or the like into the hole 61 and painting the entire surface of the cover member 52 with the hole 61 closed.

As described above, the shaft portion 58b of the fixing bolt 58 is inserted into the hole 61 of the cover member 52. FIG. 5 is an enlarged cross-sectional view showing a portion through which the fixing bolt 58 is inserted. As shown in FIG. 5, the shaft portion 58b of the fixing bolt 58 has a tapered portion 64 on its base end side. The tapered portion 64 is formed in a tapered shape so that the outer diameter increases toward the knob portion 58a. Therefore, the outer diameter of the tapered portion 64 is maximum at the end of the tapered portion 64 on the knob portion 58a side (in other words, at the base end of the shaft portion 58b). Further, the maximum outer diameter D1 of the tapered portion 64 is larger than the hole diameter D2 of the hole portion 61. Therefore, when the shaft portion 58b of the fixing bolt 58 is screwed into the screw hole portion 62 of the fixing fitting 53 through the hole portion 61, the tapered surface of the tapered portion 64 is inside the hole portion 61 at the opening edge of the hole portion 61. It is in contact with the surrounding surface. Thereby, the cover member 52 is electrically connected to the fixture 53 via the shaft portion 58b.

More specifically, when the fixing bolt 58 is screwed into the threaded hole 62 of the fixing bracket 53, the tapered surface of the tapered portion 64 crushes the angular shape of the opening edge of the hole 61 (in other words, the boundary between the inner circumferential surface of the hole 61 and the surface of the cover member 52), and an inclined surface 69 is formed along the tapered surface at the opening edge. Therefore, when the fixing bolt 58 is screwed into the threaded hole 62, part of the inner circumferential surface of the hole 61 becomes the inclined surface 69, and the tapered surface of the tapered portion 64 is in surface contact with the inclined surface 69.

A ground terminal block 65 is attached to the mounting surface 51a of the plate member 51. One end of a ground wire 66 is fixed to the ground terminal block 65 with a screw 67. The other end of the ground wire 66 is fixed to the plate portion 53a of the fixing bracket 53 with a screw 68. This electrically connects the fixing bracket 53 and the ground terminal block 65 via the ground wire 66. The ground wire 66 corresponds to the "ground wire" described in the claims.

One end of a ground wire 71 is fixed to the ground terminal block 65 with a screw 72 . The other end of the ground wire 71 is led out to the outside (back side) of the casing 50 through a wiring hole 73 provided in the plate member 51, and then is led to the distribution board 11 through the inside of the partition wall 37. It is extending. The other end of the ground wire 71 is connected to a ground terminal provided on the distribution board 11 (see FIG. 1). The ground terminal is grounded via a ground wire 74. In this case, each of the ground wires 71 and 74 constitutes a ground path 75, and the ground terminal block 65 is grounded via the ground path 75. Thereby, the cover member 52 is grounded via the fixture 53 and the ground terminal block 65.

The configuration of this embodiment described above provides the following excellent effects:

The cover member 52 is fixed to the fixing bracket 53 by a fixing bolt 58, and the cover member 52 is electrically connected to the fixing bracket 53 via the fixing bolt 58. In addition, a ground terminal block 65 grounded via a ground path 75 is provided on the plate member 51, and the ground terminal block 65 and the fixing bracket 53 are connected via an earth wire 66. In this case, since the cover member 52 is electrically connected to the ground terminal block 65 via the fixing bracket 53 and the earth wire 66, it is possible to ground the cover member 52 via the ground terminal block 65.

In this configuration, the grounding terminal block 65 of the plate member 51 and the cover member 52 are not connected via the ground wire, so when the cover member 52 is fixed to the fixing metal fitting 53, the handling of the cover member 52 is difficult due to the ground wire. Inconveniences such as being restricted or having the ground wire sandwiched between the cover member 52 and the plate member 51 can be avoided. Therefore, it becomes possible to perform the fixing work of the cover member 52 easily.

In addition, if the ground terminal block 65 and the cover member 52 are connected via an earth wire, there is a risk that the earth wire will be broken if the cover member 52 is accidentally dropped during the work of fixing the cover member 52. In this respect, the above configuration can avoid such a break in the wire, so it can be said to be an advantageous configuration in that respect as well.

By painting the surface of the cover member 52, it is possible to prevent the design from being impaired when the vehicle connection device 40 is attached to the wall surface 37a inside the building 10. In addition, by also painting the back surface of the cover member 52, it is possible to prevent the design from being impaired when the cover member 52 is removed. Here, in a configuration in which the front and back surfaces of the cover member 52 are painted, when the cover member 52 is fixed to the fixing bracket 53, a paint film is interposed between the back surface of the cover member 52 and the fixing bracket 53. For this reason, the insulating properties of the paint film make it difficult to directly and electrically connect the cover member 52 and the fixing bracket 53.

Therefore, in the above embodiment, the inner surface of the hole 61 in the cover member 52 through which the shaft 58b of the fixing bolt 58 is inserted is not painted, and the shaft 58b is inserted into the hole 61 while in contact with the inner surface of the hole 61. In this case, even if both the front and back surfaces of the cover member 52 are painted, the cover member 52 and the fixing bracket 53 can be electrically connected via the shaft 58b. Therefore, even in this configuration, the cover member 52 can be grounded via the fixing bracket 53 and the ground terminal block 65.

The proximal end side of the shaft portion 58b of the fixing bolt 58 is made into a tapered portion 64 whose diameter is expanded toward the knob portion 58a side, and the maximum outer diameter D1 of the tapered portion 64 is made larger than the hole diameter D2 of the hole portion 61. In this case, by screwing the fixing bolt 58 (shaft portion 58b) into the fixing fitting 53 through the hole 61, the tapered surface of the tapered portion 64 collapses the square shape of the opening edge of the hole 61, and the opening edge is formed with a taper. An inclined surface 69 can be formed along the surface. This inclined surface 69 is a part of the inner circumferential surface of the hole 61, and when the fixing bolt 58 is screwed into the fixing fitting 53, the tapered surface of the tapered portion 64 comes into surface contact with this inclined surface 69. Therefore, it becomes possible to reliably electrically connect the cover member 52 and the fixture 53 via the shaft portion 61b.

The present invention is not limited to the above embodiment, and may be implemented, for example, as follows.

- In the above embodiment, the fixing bolt 58 is screwed into the fixing bracket 53 through the hole 61 of the cover member 52, and the tapered surface of the tapered portion 64 crushes the opening edge of the hole 61 to form the inclined surface 69. However, such an inclined surface 69 may be formed in advance when machining the hole 61.

- In the above embodiment, the tapered portion 64 was provided on the shaft portion 58b of the fixing bolt 58, but such a tapered portion 64 does not necessarily need to be provided. Also in this case, when inserting the shaft portion 58b of the fixing bolt 58 into the hole 61 of the cover member 52, by bringing the shaft portion 58b into contact with the inner circumferential surface of the hole 61, the cover member 52 and the fixing metal fitting 53 are connected. can be electrically connected via the shaft portion 58b. Further, in this case, in order to make it easier for the shaft portion 58b to come into contact with the inner circumferential surface of the hole portion 61, it is desirable that the hole diameter of the hole portion 61 be approximately the same size as the outer diameter of the shaft portion 58b.

- In the above embodiment, a hand-tight fixing bolt 58 whose head is a knob portion 58a is used as a fastener for fixing the cover member 52, but a screwdriver tightener having a groove portion into which the tip of a screwdriver is inserted into the head may be used. bolts may be used. Further, other fasteners such as screws may be used in addition to bolts.

- In the above embodiment, the front and back surfaces of the cover member 52 are each painted, but it is also possible that the back surface of the cover member 52 is not painted, or that both the front and back surfaces of the cover member 52 are not painted. In such cases, since no paint film is interposed between the cover member 52 and the fixing bracket 53 when the cover member 52 is fixed to the fixing bracket 53, the cover member 52 and the fixing bracket 53 can be directly and electrically connected. Therefore, in such cases, it is possible to use, for example, a resin bolt with a shaft portion 58b made of resin as the fixing bolt 58.

- In the above embodiment, the fixing fitting 53 as a fixing part was provided separately from the plate member 51 on the outer circumferential side of the plate member 51, but the plate can be fixed by welding and fixing the fixing fitting to the outer circumferential side of the plate member 51. It may be provided integrally with the member 51.

- For example, when fixing the earth wire 66 to the fixing bracket 53, a screw 57 may be used to fix the fixing bracket 53 to the wall surface 37a. In other words, the screw 57 may be used to fix the fixing bracket 53 to the wall surface 37a and the earth wire 66 may be fixed to the fixing bracket 53. In this case, it is possible to reduce the number of screws.

- In the above embodiment, the grounding structure of the present invention is applied to the vehicle connection device 40 as an electrical equipment box, but the grounding structure of the present invention may also be applied to other wall-mounted electrical equipment boxes.

DESCRIPTION OF SYMBOLS 10... Building, 37a... Wall surface, 40... Vehicle connection device as an electrical box, 41... Ground fault detection part as an electrical component, 42... Earth leakage breaker as an electrical component, 50... Housing part, 51... Plate member , 52... Cover member, 53... Fixing metal fitting as a fixing part, 58... Fixing bolt as a fastener, 58a... Knob part as a head, 58b... Shaft part, 61... Hole part, 64... Taper part, 65... Ground terminal block, 66...ground wire, 75...ground path.

Claims (3)

An electrical box containing electrical components is attached to the wall inside the building.
The electrical box is
a plate member fixed to the wall surface and having the electrical component attached thereto;
a metal fixing part provided on the outer peripheral side of the plate member;
a metal cover member provided to accommodate the plate member and the fixing part inside, and fixed to the fixing part using a fastener,
The plate member is provided with a ground terminal block grounded via a ground path,
A grounding structure for an electrical equipment box, wherein the grounding terminal block and the fixed part are connected via a grounding wire. Both the front and back surfaces of the cover member are painted,
The fastener has a head and a metal shaft, and the shaft is screwed into the fixing part through a hole provided in the cover member, thereby fixing the cover member to the fixing part. and
The inner peripheral surface of the hole is not coated,
The grounding structure for an electrical equipment box according to claim 1, wherein the shaft portion is inserted into the hole while being in contact with an inner circumferential surface of the hole. The shaft portion has a tapered portion on its proximal end side, the diameter of which increases toward the head,
The grounding structure for an electrical equipment box according to claim 2, wherein the tapered portion has a maximum diameter larger than the hole diameter of the hole.

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