Grounding resistance measurement terminal device and grounding resistance measurement terminal device unit

Abstract

To provide a grounding resistance measuring terminal device with which it is possible to easily add grounding electrodes and measure grounding resistance.SOLUTION: The grounding resistance measuring terminal device comprises: an apparatus terminal that is electrically connected to an electric apparatus; a first grounding terminal that is electrically connected to a first grounding line; a second grounding terminal that is electrically connected to a second grounding line; a first opening / closing member that electrically connects the apparatus terminal and the first grounding terminal together in a closed state and electrically cuts off the apparatus terminal from the first grounding terminal in an open state; and a second opening / closing member that electrically connects the first grounding terminal and the second grounding terminal together in a closed state and electrically cuts off the first grounding terminal from the second grounding terminal in an open state.SELECTED DRAWING: Figure 2

Description

[[Technical Field]]

[0001] The present disclosure relates to a ground resistance measurement terminal device and a ground resistance measurement terminal device unit. [[Background Art]]

[0002] Patent Document 1 discloses a connector for ground resistance measurement, which is an example of a ground resistance measurement terminal device. The connector for ground resistance measurement disclosed in Patent Document 1 includes a terminal conductor electrically connected to a ground wire portion on a transformer side, a terminal conductor electrically connected to a ground wire portion on a ground side, and a sliding contact clip that electrically connects and disconnects the two terminal conductors. [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2003-185687 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] In the connector for ground resistance measurement (ground resistance measurement terminal device) of Patent Document 1, the ground resistance of the ground electrode is measured in a state where the transformer and the ground (ground electrode) are electrically disconnected by the sliding contact clip. The measurement of ground resistance is performed at regular intervals. When the ground resistance becomes larger than a specified value due to aging or other factors, it is required to reduce the ground resistance to the specified value or lower through repair work of the ground electrode, addition of a ground electrode, or the like. In the ground resistance measurement terminal device of Patent Document 1, when adding a ground electrode, it is necessary to work to directly electrically connect the ground wire from the added ground electrode to the ground wire from the existing ground electrode.

[0005] Furthermore, when measuring the grounding resistance after connecting an additional grounding wire to an existing grounding wire, it is necessary to measure the grounding resistance of each of the two grounding electrodes individually, as well as the combined grounding resistance of the two grounding electrodes. When measuring the grounding resistance of each of the two grounding electrodes individually, the grounding resistance measuring terminal device described in Patent Document 1 requires electrically disconnecting the existing grounding wire and the additional grounding wire, i.e., cutting the grounding wires. Also, after measuring the grounding resistance, it is necessary to electrically reconnect the cut grounding wires directly. Therefore, adding grounding electrodes and measuring grounding resistance cannot be done easily, and the measurement time for grounding resistance becomes relatively long.

[0006] This disclosure has been made in view of the above-mentioned problems, and aims to provide a grounding resistance measuring terminal device that can easily perform the addition of a grounding electrode and the measurement of grounding resistance. [Means for solving the problem]

[0007] To achieve the above objective, a ground resistance measuring terminal device according to one aspect of the present disclosure includes: an equipment terminal electrically connected to an electrical device; a first ground terminal electrically connected to a first ground wire; a second ground terminal electrically connected to a second ground wire; a first switching member that electrically connects the equipment terminal and the first ground terminal when in a closed state and electrically disconnects the equipment terminal and the first ground terminal when in an open state; and a second switching member that electrically connects the first ground terminal and the second ground terminal when in a closed state and electrically disconnects the first ground terminal and the second ground terminal when in an open state.

[0008] According to this, when the first grounding wire is electrically connected to the grounding resistance measuring terminal device, and the second grounding wire is not electrically connected, the second grounding wire can be added by electrically connecting the second grounding wire to the second grounding terminal, without electrically connecting the second grounding wire to the first grounding wire. Therefore, a grounding electrode can be easily added.

[0009] Furthermore, when both the first and second switching members are in the closed state, the combined grounding resistance corresponding to the first and second grounding wires can be measured by opening the first switching member. Also, by opening both the first and second switching members, the grounding resistance corresponding to the first grounding wire and the grounding resistance corresponding to the second grounding wire can be measured separately. In other words, the combined grounding resistance corresponding to the first and second grounding wires, the grounding resistance corresponding to the first grounding wire, and the grounding resistance corresponding to the second grounding wire can be easily measured by operating the first and second switching members.

[0010] Furthermore, in a preferred embodiment of the grounding resistance measuring terminal device according to one embodiment, the grounding resistance measuring terminal device further comprises a conductive member and a third switching member that electrically connects the conductive member and the first grounding terminal when in a closed state and electrically disconnects the conductive member and the first grounding terminal when in an open state, wherein the first switching member electrically connects the conductive member and the equipment terminal when in a closed state and electrically disconnects the conductive member and the equipment terminal when in an open state, and the second switching member electrically connects the conductive member and the second grounding terminal when in a closed state and electrically disconnects the conductive member and the second grounding terminal when in an open state.

[0011] If the grounding resistance measuring terminal device does not have a third switching member, the first and second switching members are both in the closed state. Therefore, when measuring the grounding resistance corresponding to the first grounding wire and the grounding resistance corresponding to the second grounding wire, both the first and second switching members must be in the open state. On the other hand, with the grounding resistance measuring terminal device of this embodiment, the grounding resistance corresponding to the first grounding wire can be measured by opening the third switching member when the first, second, and third switching members are all in the closed state. After measuring the grounding resistance, the third switching member can be closed to easily ground the electrical equipment.

[0012] Furthermore, by opening the second switching member when the first, second, and third switching members are all in the closed state, the grounding resistance corresponding to the second grounding wire can be measured. Then, by closing the second switching member after measuring the grounding resistance, electrical equipment can be easily grounded.

[0013] In other words, by operating one of the second and third switching members, the grounding resistance corresponding to the first grounding wire and the grounding resistance corresponding to the second grounding wire can be measured. Furthermore, electrical equipment can be easily grounded after measuring the grounding resistance. Therefore, the grounding resistance corresponding to the first grounding wire and the grounding resistance corresponding to the second grounding wire can be easily measured.

[0014] Furthermore, in a preferred embodiment of the grounding resistance measuring terminal device according to one aspect, the grounding resistance measuring terminal device further comprises a third grounding terminal and a fourth switching member that electrically connects the second grounding terminal and the third grounding terminal when in a closed state and electrically disconnects the second grounding terminal and the third grounding terminal when in an open state.

[0015] According to this, a grounding wire can be electrically connected to the third grounding terminal. In other words, a third grounding wire can be easily added. Furthermore, by opening the fourth switching member, the grounding resistance corresponding to the added grounding wire can be easily measured. In addition, a grounding resistance measurement terminal device can be added via the third grounding terminal. Thus, three or more grounding wires can be easily added.

[0016] Furthermore, in a preferred embodiment of the grounding resistance measuring terminal device according to one aspect, the first opening / closing member is a screw member that electrically connects the equipment terminal and the first grounding terminal when tightened and electrically disconnects the equipment terminal and the first grounding terminal when loosened.

[0017] According to this configuration, the first opening / closing member is a screw member, and the operation of the first opening / closing member can be performed with one hand. In other words, the operation of the first opening / closing member during earth resistance measurement can be performed more easily.

[0018] Further, to achieve the above object, a ground resistance measurement terminal device unit according to an aspect of the present disclosure includes two of the above-described ground resistance measurement terminal devices, and further includes a connecting member that electrically connects the third ground terminal of one of the two ground resistance measurement terminal devices to the device terminal of the other of the two ground resistance measurement terminal devices.

[0019] According to this configuration, a third ground wire and a fourth ground wire can be easily added. Therefore, a ground electrode can be easily added.

Effects of the Invention

[0020] According to the present disclosure, it is possible to provide a ground resistance measurement terminal device that can simplify addition of a ground electrode and measurement of ground resistance.

Brief Description of Drawings

[0021] [Figure 1] FIG. 1 is a schematic diagram showing a state where a ground resistance measurement terminal device according to an embodiment of the present disclosure is installed on a utility pole. [Figure 2] FIG. 2 is an exploded perspective view of the ground resistance measurement terminal device. [Figure 3] FIG. 3 is a cross-sectional view of the ground resistance measurement terminal device showing the first opening / closing member in a closed state. [Figure 4] FIG. 4 is a cross-sectional view of the ground resistance measurement terminal device showing the first opening / closing member in an open state. [Figure 5] FIG. 5 is a plan view of a ground resistance measurement terminal device 1 to which a first ground electrode is connected via a first ground wire. [Figure 6A] FIG. 6A is a schematic diagram showing a method for measuring the ground resistance of the first ground electrode. [Figure 6B] FIG. 6B is a diagram showing detection values of a voltmeter shown in FIG. 6A. [Figure 7] FIG. 7 is a circuit diagram of the ground resistance measurement terminal device of FIG. 2 when a device terminal is grounded to the first ground electrode and the second ground electrode. [Figure 8] FIG. 8 is a circuit diagram of the ground resistance measurement terminal device of FIG. 2 when measuring the ground resistance of the first ground electrode. [Figure 9] FIG. 9 is a circuit diagram of the ground resistance measurement terminal device of FIG. 2 when measuring the ground resistance of the second ground electrode. [Figure 10] FIG. 10 is a circuit diagram of the ground resistance measurement terminal device of FIG. 2 when measuring the combined ground resistance of the first ground electrode and the second ground electrode. [Figure 11] FIG. 11 is a plan view of a main body portion of a ground resistance measurement terminal device according to a modification of the embodiment of the present disclosure. [Figure 12] FIG. 12 is a circuit diagram of the ground resistance measurement terminal device of FIG. 11 when measuring the ground resistance of the first ground electrode. [Figure 13] FIG. 13 is a circuit diagram of the ground resistance measurement terminal device of FIG. 11 when measuring the ground resistance of the second ground electrode. [Figure 14] FIG. 14 is a circuit diagram of the ground resistance measurement terminal device of FIG. 11 when measuring the ground resistance of the third ground electrode. [Figure 15] FIG. 15 is a circuit diagram of the ground resistance measurement terminal device 1 of FIG. 11 when measuring the combined ground resistance of the first ground electrode, the second ground electrode and the third ground electrode. [Figure 16] FIG. 16 is a plan view of a ground resistance measurement terminal device unit according to an embodiment of the present disclosure. DESCRIPTION OF EMBODIMENTS

[0022] The present disclosure will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the embodiments described below. Furthermore, the components in the embodiments below include those easily conceivable by those skilled in the art, those substantially identical, and those within the scope of equivalents. Moreover, the components disclosed in the embodiments below can be combined as appropriate.

[0023] <Earth resistance measurement terminal device> Figure 1 is a schematic diagram showing the grounding resistance measuring terminal device 1 according to the present disclosure installed on a utility pole 3.

[0024] The grounding resistance measuring terminal device 1 is used when grounding electrical equipment 2. Electrical equipment 2 includes, for example, transformers, lightning arresters, and high-voltage equipment. The grounding resistance measuring terminal device 1 shown in Figure 1 is used for grounding electrical equipment 2 installed on a utility pole 3.

[0025] The grounding resistance measuring terminal device 1 is installed at a relatively high position on the utility pole 3 via a band 4. The grounding resistance measuring terminal device 1 is electrically connected to the electrical equipment 2 via a conductor 2a and is connected to the first grounding electrode 5 via a first grounding wire 5a.

[0026] Figure 2 is an exploded perspective view of the grounding resistance measuring terminal device 1. In the following description, the width direction of the grounding resistance measuring terminal device 1 is defined as the X direction, the depth direction of the grounding resistance measuring terminal device 1 is defined as the Y direction, and the height direction of the grounding resistance measuring terminal device 1 is defined as the Z direction. In this specification, "plan view" means viewing the grounding resistance measuring terminal device 1 from the +Z side along the Z direction. Note that the X, Y, and Z directions are examples, and this disclosure is not limited to these directions.

[0027] The ground resistance measuring terminal device 1 comprises a main body 10 and a cover 20. The main body 10 is rectangular parallelepiped. It goes without saying that the main body 10 is not limited to being rectangular parallelepiped. The material of the main body 10 is electrically insulating. The bottom of the main body 10 is provided with a mounting hole 10a through which the band 4 passes. The side wall on the +X side and the side wall on the -X side of the main body 10 have a pair of rail portions 10b extending along the Y direction.

[0028] Furthermore, the upper surface of the main body 10 is equipped with a device terminal 30, a first grounding terminal 31, a second grounding terminal 32, a third grounding terminal 33, a conductive member 40, a first switching member 41, a second switching member 42, a third switching member 43, and a fourth switching member 44. The device terminal 30, the first grounding terminal 31, the second grounding terminal 32, the third grounding terminal 33, and the conductive member 40 are spaced apart from each other.

[0029] The device terminal 30 is electrically connected to the electrical equipment 2 via a conductor 2a. The device terminal 30 is located on the upper surface of the main body 10, on the -X side and the +Y side. The device terminal 30 includes a first bottom plate 30a, a first pressing plate 30b, and a first mounting screw 30c.

[0030] The first base plate 30a is rectangular in plan view. The first pressing plate 30b overlaps the +Y side of the first base plate 30a in plan view. The threaded portion of the first mounting screw 30c penetrates the first base plate 30a and the first pressing plate 30b and is fitted into the main body 10.

[0031] The conductor 2a is positioned between the first base plate 30a and the first pressure plate 30b. When the first mounting screw 30c is tightened, the head of the first mounting screw 30c presses against the first pressure plate 30b, and the conductor 2a is sandwiched between the first base plate 30a and the first pressure plate 30b. This electrically connects the equipment terminal 30 and the electrical equipment 2.

[0032] The first grounding terminal 31 is electrically connected to the first grounding wire 5a. The first grounding terminal 31 is located on the -X side and -Y side of the upper surface of the main body 10. The first grounding terminal 31 comprises a second bottom plate 31a, a second pressing plate 31b, and a second mounting screw 31c. The second bottom plate 31a is rectangular in plan view. The second pressing plate 31b overlaps with the -Y side of the second bottom plate 31a in plan view. The threaded portion of the second mounting screw 31c penetrates the second bottom plate 31a and the second pressing plate 31b and is fitted into the main body 10.

[0033] The first grounding wire 5a is positioned between the second base plate 31a and the second pressing plate 31b. When the second mounting screw 31c is tightened, the head of the second mounting screw 31c presses against the second pressing plate 31b, and the first grounding wire 5a is sandwiched between the second base plate 31a and the second pressing plate 31b. This electrically connects the first grounding terminal 31 and the first grounding pole 5.

[0034] The second grounding terminal 32 is located on the upper surface of the main body 10, on the +X side and the -Y side. The second grounding terminal 32 comprises a third bottom plate 32a, a third pressing plate 32b, and a third mounting screw 32c. The third bottom plate 32a is rectangular in plan view. The third pressing plate 32b overlaps with the -Y side of the third bottom plate 32a in plan view. The threaded portion of the third mounting screw 32c penetrates the third bottom plate 32a and the third pressing plate 32b and is fitted into the main body 10.

[0035] The third grounding terminal 33 is located on the upper surface of the main body 10, on both the +X and +Y sides. The third grounding terminal 33 comprises a fourth bottom plate 33a, a fourth pressing plate 33b, and a fourth mounting screw 33c. The fourth bottom plate 33a is rectangular in plan view. The fourth pressing plate 33b overlaps with the +Y side of the fourth bottom plate 33a in plan view. The threaded portion of the fourth mounting screw 33c penetrates the fourth bottom plate 33a and the fourth pressing plate 33b and is fitted into the main body 10. It goes without saying that the first bottom plate 30a, the second bottom plate 31a, the third bottom plate 32a, and the fourth bottom plate 33a are not limited to being rectangular in plan view.

[0036] The conductive member 40 is a conductive plate-shaped member. The conductive member 40 extends along the X direction and is positioned between the equipment terminal 30 and the first ground terminal 31, and between the second ground terminal 32 and the third ground terminal 33.

[0037] The first switching member 41 electrically connects the equipment terminal 30 and the first ground terminal 31 when in the closed state S1, and electrically disconnects the equipment terminal 30 and the first ground terminal 31 when in the open state S2. The first switching member 41 is a screw member that electrically connects the equipment terminal 30 and the first ground terminal 31 when tightened, and electrically disconnects the equipment terminal 30 and the first ground terminal 31 when loosened.

[0038] Specifically, the first switching member 41 is positioned between the conductive member 40 and the equipment terminal 30, electrically connecting the conductive member 40 and the equipment terminal 30 when in the closed state S1, and electrically disconnecting the conductive member 40 and the equipment terminal 30 when in the open state S2.

[0039] Figure 3 is a cross-sectional view of the ground resistance measuring terminal device 1 showing the first opening / closing member 41 in the closed state S1. The first opening / closing member 41 has a screw portion 41a and a head 41b. The screw portion 41a is fitted into the main body 10. A flange 41c is arranged around the entire circumference of the head 41b. In other words, the first opening / closing member 41 is a screw member with a flange. The head 41b also has a groove 41b1 into which a tool such as a screwdriver can be fitted.

[0040] When the first opening / closing member 41 is tightened against the main body 10, the first opening / closing member 41 enters a closed state S1. When the first opening / closing member 41 is in the closed state S1, the first bottom plate 30a of the conductive member 40 and the first bottom plate 30a of the equipment terminal 30 each come into contact with the head 41b, and the conductive member 40 and the equipment terminal 30 are electrically connected via the head 41b.

[0041] Figure 4 is a cross-sectional view of the ground resistance measuring terminal device 1 showing the first opening / closing member 41 in the open state S2. When the first opening / closing member 41 is loosened from the main body 10, the first opening / closing member 41 enters the open state S2. When the first opening / closing member 41 is in the open state S2, the first bottom plate 30a of the conductive member 40 and the equipment terminal 30 are separated from the head 41b, and the conductive member 40 and the equipment terminal 30 are electrically isolated. If the first opening / closing member 41 is a screw member, the operator can operate the first opening / closing member 41 with one hand using a tool such as a screwdriver, making it easy to operate the first opening / closing member 41. The first opening / closing member 41 may also be a screw member without a groove 41b1 (for example, a hexagonal bolt).

[0042] The second switching member 42 shown in Figure 2 electrically connects the first grounding terminal 31 and the second grounding terminal 32 when in the closed state S1, and electrically disconnects the first grounding terminal 31 and the second grounding terminal 32 when in the open state S2. Specifically, the second switching member 42 is positioned between the conductive member 40 and the second grounding terminal 32, electrically connecting the conductive member 40 and the second grounding terminal 32 when in the closed state S1, and electrically disconnecting the conductive member 40 and the second grounding terminal 32 when in the open state S2. The second switching member 42 is a screw member and is configured in the same way as the first switching member 41.

[0043] The second switching member 42, like the first switching member 41, is tightened and loosened relative to the main body 10. As a result, the second switching member 42 electrically connects and disconnects the conductive member 40 and the third bottom plate 32a of the second grounding terminal 32.

[0044] The third switching member 43 electrically connects the conductive member 40 and the first ground terminal 31 when in the closed state S1, and electrically disconnects the conductive member 40 and the first ground terminal 31 when in the open state S2. The third switching member 43 is positioned between the conductive member 40 and the first ground terminal 31. The third switching member 43 is a screw member and is configured similarly to the first switching member 41.

[0045] The third switching member 43, like the first switching member 41, is tightened and loosened relative to the main body 10. This allows the third switching member 43 to electrically connect and disconnect the conductive member 40 from the second bottom plate 31a of the first grounding terminal 31. Furthermore, when the first switching member 41 and the second switching member 42 are in the open state S2 and the closed state S1, respectively, the third switching member 43 electrically connects the conductive member 40 to the first grounding terminal 31 when in the closed state S1, and electrically disconnects the conductive member 40 from the first grounding terminal 31 when in the open state S2.

[0046] Furthermore, when the second switching member 42 and the third switching member 43 are in the closed state S1, the first grounding terminal 31 and the second grounding terminal 32 are electrically connected, and when the second switching member 42 is in the open state S2, the first grounding terminal 31 and the second grounding terminal 32 are electrically disconnected. In other words, when the third switching member 43 is in the closed state S1, and the first switching member 41 is in the open state S2 and the closed state S1, the second switching member 42 electrically connects the first grounding terminal 31 and the second grounding terminal 32 when it is in the closed state S1, and electrically disconnects the first grounding terminal 31 and the second grounding terminal 32 when it is in the open state S2.

[0047] Furthermore, when the third switching member 43 is in the closed state S1, and the second switching member 42 is in the open state S2 and the closed state S1, the first switching member 41 electrically connects the equipment terminal 30 and the first ground terminal 31 when it is in the closed state S1, and electrically disconnects the equipment terminal 30 and the first ground terminal 31 when it is in the open state S2.

[0048] The fourth switching member 44 electrically connects the second grounding terminal 32 and the third grounding terminal 33 when in the closed state S1, and electrically disconnects the second grounding terminal 32 and the third grounding terminal 33 when in the open state S2. Specifically, the fourth switching member 44 is positioned between the conductive member 40 and the third grounding terminal 33, and electrically connects and disconnects the conductive member 40 and the third grounding terminal 33. The fourth switching member 44 is a screw member and is configured in the same way as the first switching member 41.

[0049] Furthermore, the fourth switching member 44, like the first switching member 41, can be tightened or loosened relative to the main body 10. As a result, the fourth switching member 44 electrically connects and disconnects the conductive member 40 and the fourth bottom plate 33a of the third grounding terminal 33. In other words, when the second switching member 42 is in the closed state S1, and the first switching member 41 and the third switching member 43 are in the open state S2 and closed state S1, respectively, the fourth switching member 44 electrically connects the second grounding terminal 32 and the third grounding terminal 33 when in the closed state S1, and electrically disconnects the second grounding terminal 32 and the third grounding terminal 33 when in the open state S2.

[0050] Furthermore, the ground resistance measuring terminal device 1 is further equipped with a fifth mounting screw 45. The fifth mounting screw 45 secures the conductive member 40 to the main body 10. The threaded portion of the fifth mounting screw 45 passes through the conductive member 40 and is fitted into the main body 10.

[0051] Furthermore, when the fifth mounting screw 45 is attached to the main body 10, paint and adhesive are applied to the groove in the head of the fifth mounting screw 45 into which a tool fits. This closes the groove in the head of the fifth mounting screw 45, preventing tools such as screwdrivers used to open and close the first opening / closing member 41 from getting stuck in the groove. Therefore, when measuring the grounding resistance described later, it is possible to prevent the fifth mounting screw 45 from being removed by the tool used to open and close the first opening / closing member 41, and the conductive member 40 from coming off the main body 10. The dashed line of the fifth mounting screw 45 shown in Figure 2 indicates that the groove in the head of the fifth mounting screw 45 is closed. Note that the fifth mounting screw 45 may be a screw member that is different from the tool used to attach the fifth mounting screw 45 and the tool used to open and close the first opening / closing member 41, for example, a hexagonal bolt without a groove in its head may be used.

[0052] The lid portion 20 covers the upper surface of the main body portion 10. The lid portion 20 has a U-shaped cross-section that is open on the -Z side. The side walls of the lid portion 20 on the +X side and the side walls on the -X side have a pair of grooves 20a that extend along the Y direction.

[0053] The pair of grooves 20a are slidably fitted into the pair of rails 10b of the main body 10 along the Y direction. This allows the lid 20 to be slidably attached to the main body 10 along the Y direction. In other words, as the lid 20 slides relative to the main body 10 along the Y direction, the lid 20 opens and closes the +Z side (i.e., top surface) of the main body 10.

[0054] Figure 5 is a plan view of the grounding resistance measuring terminal device 1, to which the first grounding electrode 5 is connected via the first grounding wire 5a. The pair of rail sections 10b each have a protrusion 10b1. The pair of grooves 20a each have a recess 20a1 into which the protrusion 10b1 fits when the lid section 20 is attached to the main body section 10. Figure 5 shows the state in which the protrusion 10b1 is fitted into the recess 20a1. The fitting of the protrusion 10b1 into the recess 20a1 prevents the lid section 20 from coming off the main body section 10.

[0055] Furthermore, the lid portion 20 has a side wall 20b that contacts the +Y side of the main body portion 10 when the lid portion 20 is attached to the main body portion 10. In other words, the lid portion 20 is removed from the main body portion 10 by sliding the lid portion 20 toward the +Y side from the state in which it is attached to the main body portion 10.

[0056] In a state where the first grounding electrode 5 is connected to such a grounding resistance measuring terminal device 1 via the first grounding wire 5a, and the first switching member 41 is in the closed state S1 and the third switching member 43 is in the closed state S1, the equipment terminal 30 and the first grounding terminal 31 are electrically connected via the conductive member 40, and the equipment terminal 30 is grounded.

[0057] Next, the method for measuring the grounding resistance of the first grounding electrode 5 will be explained. The grounding resistance is measured with the cover 20 removed from the main body 10. When measuring the grounding resistance of the first grounding electrode 5, one of the first switching member 41 and the third switching member 43 is set to the open state S2, and the first grounding electrode 5 and the electrical equipment 2 are electrically disconnected. This allows for accurate measurement of the grounding resistance of the first grounding electrode 5.

[0058] Figure 6A is a schematic diagram showing the method for measuring the grounding resistance of the first grounding electrode 5. Figure 6B shows the detected value of the voltmeter VM shown in Figure 6A. In Figure 6B, the horizontal axis shows the positions of the first grounding electrode 5, the first auxiliary electrode E1, and the second auxiliary electrode E2, and the vertical axis shows the detected value of the voltmeter VM.

[0059] As shown in Figure 6A, when measuring the grounding resistance of the first grounding electrode 5, the first auxiliary electrode E1 is buried in the ground at a distance of 10 m or more from the first grounding electrode 5, and the second auxiliary electrode E2 is buried in the ground between the first grounding electrode 5 and the first auxiliary electrode E1. The first grounding electrode 5 and the first auxiliary electrode E1 are then electrically connected via an oscillator OC, and an ammeter AM is electrically connected in series with the oscillator OC. Furthermore, a voltmeter VM is placed to measure the potential difference between the first grounding electrode 5 and the second auxiliary electrode E2.

[0060] As shown in Figure 6B, when the oscillator OC outputs a voltage of a predetermined frequency, the potential difference between the first grounding electrode 5 and the second auxiliary electrode E2 becomes almost flat in the vicinity of the placement position of the second auxiliary electrode E2. If the detected value of the voltmeter VM is V1 and the detected value of the ammeter AM is I1, the grounding resistance R1 of the first grounding electrode 5 can be calculated by dividing the detected value of the voltmeter VM by the detected value of the ammeter AM (R1 = V1 / I1).

[0061] If the grounding resistance of the first grounding electrode 5 exceeds the specified value, it is mandatory to reduce the grounding resistance to below the specified value through repair work on the grounding electrode or by adding a grounding electrode.

[0062] Next, we will describe the case in which a second grounding electrode is added to the grounding resistance measurement terminal device 1, starting from a state where the first grounding electrode 5 is connected to the grounding resistance measurement terminal device 1 via the first grounding wire 5a. In this case, the cover portion 20 is removed from the main body portion 10, and the second grounding terminal 32 is visible, and the second grounding electrode is connected to the grounding resistance measurement terminal device 1 via the second grounding wire 6a.

[0063] As shown in Figure 5, the second grounding wire 6a is positioned between the third bottom plate 32a and the third pressing plate 32b of the second grounding terminal 32. When the third mounting screw 32c is tightened, the head of the third mounting screw 32c presses against the third pressing plate 32b, and the second grounding wire 6a is sandwiched between the third bottom plate 32a and the third pressing plate 32b. This electrically connects the second grounding terminal 32 and the second grounding electrode. Furthermore, when the first switching member 41 is in the closed state S1 and the second switching member 42 is in the closed state S1, the equipment terminal 30 and the second grounding terminal 32 are electrically connected via the conductive member 40, and the equipment terminal 30 is grounded by the second grounding electrode.

[0064] Furthermore, when a third grounding electrode is added and connected to the grounding resistance measuring terminal device 1 via a third grounding wire 7a, the third grounding wire 7a is positioned between the fourth bottom plate 33a and the fourth pressing plate 33b of the third grounding terminal 33, with the third grounding terminal 33 visible. When the fourth mounting screw 33c is tightened, the head of the fourth mounting screw 33c presses against the fourth pressing plate 33b, and the third grounding wire 7a is sandwiched between the fourth bottom plate 33a and the fourth pressing plate 33b. As a result, the third grounding terminal 33 and the third grounding electrode are electrically connected. Also, when the first switching member 41 is in the closed state S1 and the fourth switching member 44 is in the closed state S1, the equipment terminal 30 and the third grounding terminal 33 are electrically connected via the conductive member 40, and the equipment terminal 30 is grounded by the third grounding electrode.

[0065] Next, we will describe the case in which the grounding resistance of the first grounding electrode 5, the grounding resistance of the second grounding electrode 6, and the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6 are measured in the grounding resistance measuring terminal device 1, where the equipment terminal 30 is grounded to the first grounding electrode 5 and the second grounding electrode 6.

[0066] Figure 7 is a circuit diagram of the grounding resistance measuring terminal device 1 shown in Figure 2 when the equipment terminal 30 is grounded to the first grounding electrode 5 and the second grounding electrode 6. In the grounding resistance measuring terminal device 1 shown in Figure 7, the first switching member 41, the second switching member 42, the third switching member 43, and the fourth switching member 44 are each in the closed state S1. However, as shown in Figure 7, if the third grounding electrode is not connected to the grounding resistance measuring terminal device 1, the fourth switching member 44 may be in the open state S2.

[0067] Figure 8 is a circuit diagram of the grounding resistance measuring terminal device 1 shown in Figure 2 when measuring the grounding resistance of the first grounding electrode 5. When measuring the grounding resistance of the first grounding electrode 5, the first switching member 41, the second switching member 42, and the third switching member 43 shown in Figure 7 are all in a closed state S1, and the third switching member 43 is opened to a state S2.

[0068] As a result, the first grounding terminal 31, the first grounding wire 5a, and the first grounding electrode 5 are electrically isolated from the conductive member 40, the equipment terminal 30, the second grounding terminal 32, and the third grounding terminal 33, allowing the grounding resistance of the first grounding electrode 5 to be measured. In this case, the first grounding electrode 5 and the electrical equipment 2 are electrically isolated, allowing the grounding resistance of the first grounding electrode 5 to be measured with high accuracy.

[0069] Figure 9 is a circuit diagram of the grounding resistance measuring terminal device 1 shown in Figure 2 when measuring the grounding resistance of the second grounding electrode 6. When measuring the grounding resistance of the second grounding electrode 6, the first switching member 41, the second switching member 42, and the third switching member 43 shown in Figure 7 are all in a closed state S1, and the second switching member 42 is opened to a state S2.

[0070] As a result, the second grounding terminal 32, the second grounding wire 6a, and the second grounding electrode 6 are electrically isolated from the conductive member 40, the equipment terminal 30, the first grounding terminal 31, and the third grounding terminal 33, allowing the grounding resistance of the second grounding electrode 6 to be measured. In this case, the second grounding electrode 6 and the electrical equipment 2 are electrically isolated, allowing the grounding resistance of the second grounding electrode 6 to be measured with high accuracy.

[0071] Figure 10 is a circuit diagram of the grounding resistance measuring terminal device 1 shown in Figure 2 when measuring the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6. When measuring the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6, the first switching member 41, the second switching member 42, and the third switching member 43 shown in Figure 7 are each in a closed state S1, and the first switching member 41 is opened to a state S2.

[0072] As a result, the first grounding terminal 31 and the second grounding terminal 32 are electrically connected to each other, while being electrically isolated from the equipment terminal 30. Therefore, the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6 can be measured. In this case, the first grounding electrode 5 and the second grounding electrode 6 are electrically isolated from the electrical equipment 2, and the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6 can be measured with accuracy.

[0073] Next, we will describe the case in which the grounding resistance of the third grounding electrode is measured in the grounding resistance measuring terminal device 1, in which the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode are grounded to the equipment terminal 30. In this case, the first switching member 41, the second switching member 42, the third switching member 43, and the fourth switching member 44 shown in Figure 7 are all in a closed state S1, and the fourth switching member 44 is opened to an open state S2.

[0074] As a result, the third grounding terminal 33, the third grounding wire 7a, and the third grounding electrode are electrically isolated from the conductive member 40, the equipment terminal 30, the first grounding terminal 31, and the second grounding terminal 32, allowing the grounding resistance of the third grounding electrode to be measured. In this case, the third grounding electrode and the electrical equipment 2 are electrically isolated, allowing the grounding resistance of the third grounding electrode to be measured with high accuracy.

[0075] Furthermore, when measuring the combined grounding resistance of the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode, the first switching member 41, the second switching member 42, the third switching member 43, and the fourth switching member 44 shown in Figure 7 are each in a closed state S1, and the first switching member 41 is opened to the open state S2.

[0076] As a result, the first grounding terminal 31, the second grounding terminal 32, and the third grounding terminal 33 are electrically connected to each other, while being electrically isolated from the equipment terminal 30. Therefore, the combined grounding resistance of the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode can be measured. In this case, the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode are electrically isolated from the electrical equipment 2, and the combined grounding resistance of the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode can be measured with accuracy.

[0077] As described above, according to this embodiment, the grounding resistance measuring terminal device 1 includes an equipment terminal 30 electrically connected to an electrical device 2, a first grounding terminal 31 electrically connected to a first grounding wire 5a, a second grounding terminal 32 electrically connected to a second grounding wire 6a, a first switching member 41 that electrically connects the equipment terminal 30 and the first grounding terminal 31 when in a closed state S1 and electrically disconnects the equipment terminal 30 and the first grounding terminal 31 when in an open state S2, and a second switching member 42 that electrically connects the first grounding terminal 31 and the second grounding terminal 32 when in a closed state S1 and electrically disconnects the first grounding terminal 31 and the second grounding terminal 32 when in an open state S2. According to this, when the first grounding wire 5a is electrically connected to the grounding resistance measuring terminal device 1, and the second grounding wire 6a is not electrically connected, the second grounding wire 6a can be added by electrically connecting the second grounding wire 6a to the second grounding terminal 32, without electrically connecting the second grounding wire 6a to the first grounding wire 5a. Therefore, a grounding electrode can be easily added. Furthermore, when both the first switching member 41 and the second switching member 42 are in the closed state S1, the combined grounding resistance corresponding to the first grounding wire 5a and the second grounding wire 6a (i.e., the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6) can be measured by opening the first switching member 41 in the open state S2. Also, when both the first switching member 41 and the second switching member 42 are in the closed state S1, the grounding resistance corresponding to the first grounding wire 5a (i.e., the grounding resistance of the first grounding electrode 5) and the grounding resistance corresponding to the second grounding wire 6a (i.e., the grounding resistance of the second grounding electrode 6) can be measured, respectively. In other words, the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6, the grounding resistance of the first grounding electrode 5, and the grounding resistance of the second grounding electrode 6 can be easily measured by operating the first switching member 41 and the second switching member 42.

[0078] Furthermore, the ground resistance measuring terminal device 1 further comprises a conductive member 40 and a third switching member 43 that electrically connects the conductive member 40 and the first ground terminal 31 when in a closed state S1, and electrically disconnects the conductive member 40 and the first ground terminal 31 when in an open state S2. The first switching member 41 electrically connects the conductive member 40 and the equipment terminal 30 when in a closed state S1, and electrically disconnects the conductive member 40 and the equipment terminal 30 when in an open state S2. The second switching member 42 electrically connects the conductive member 40 and the second ground terminal 32 when in a closed state S1, and electrically disconnects the conductive member 40 and the second ground terminal 32 when in an open state S2. If the ground resistance measuring terminal device 1 does not have a third switching member 43, the first switching member 41 and the second switching member 42 are both in the closed state S1. Therefore, when measuring the ground resistance of the first grounding electrode 5 and the ground resistance of the second grounding electrode 6, it is necessary to open both the first switching member 41 and the second switching member 42 S2. On the other hand, according to the grounding resistance measuring terminal device 1 of this embodiment, when the first switching member 41, the second switching member 42, and the third switching member 43 are each in the closed state S1, the grounding resistance of the first grounding electrode 5 can be measured by opening the third switching member 43 in the open state S2. Then, after measuring the grounding resistance, the electrical equipment 2 can be easily grounded by closing the third switching member 43 in the closed state S1. Furthermore, when the first switching member 41, the second switching member 42, and the third switching member 43 are all in the closed state S1, the second switching member 42 can be opened in the open state S2 to measure the grounding resistance of the second grounding electrode 6. After measuring the grounding resistance, the second switching member 42 can be closed in the closed state S1 to easily ground the electrical equipment 2. In other words, by operating one of the second switching member 42 and the third switching member 43, the grounding resistance of the first grounding electrode 5 and the grounding resistance of the second grounding electrode 6 can be measured. Furthermore, the electrical equipment 2 can be easily grounded after measuring the grounding resistance. Therefore, the grounding resistance of the first grounding electrode 5 and the grounding resistance of the second grounding electrode 6 can be easily measured.

[0079] Furthermore, the grounding resistance measuring terminal device 1 further includes a third grounding terminal 33 and a fourth switching member 44 that electrically connects the second grounding terminal 32 and the third grounding terminal 33 when in the closed state S1, and electrically disconnects the second grounding terminal 32 and the third grounding terminal 33 when in the open state S2. According to this, the third grounding wire 7a can be electrically connected to the third grounding terminal 33. In other words, a third grounding wire can be easily added. Furthermore, by opening the fourth switching member 44 (S2), the grounding resistance corresponding to the third grounding wire 7a (i.e., the grounding resistance of the third grounding electrode) can be easily measured. In addition, a grounding resistance measuring terminal device 1 can be added via the third grounding terminal 33. Thus, three or more grounding wires can be easily added.

[0080] Furthermore, the ground resistance measuring terminal device 1 has a first switching member 41 which is a screw member that electrically connects the equipment terminal 30 and the first ground terminal 31 when tightened and electrically disconnects the equipment terminal 30 and the first ground terminal 31 when loosened. According to this, the first switching member 41 is a screw member, and the first switching member 41 can be operated with one hand. In other words, the operation of the first switching member 41 during ground resistance measurement can be made even simpler. Also, the second switching member 42, the third switching member 43, and the fourth switching member 44 are also screw members, and similar to the first switching member 41, the operation of the second switching member 42, the third switching member 43, and the fourth switching member 44 during ground resistance measurement can be made simpler.

[0081] Next, a modified version of the grounding resistance measuring terminal device 1 of the above embodiment will be described, primarily focusing on the differences from the above-described grounding resistance measuring terminal device 1.

[0082] Figure 11 is a plan view of the main body 10 of the earth resistance measurement terminal device 1 according to a modified embodiment of the present disclosure. Figure 11 shows the state in which the conductor 2a, the first earth wire 5a, the second earth wire 6a, and the third earth wire 7a are electrically connected to the earth resistance measurement terminal device 1.

[0083] Compared to the ground resistance measuring terminal device 1 of the above embodiment, the ground resistance measuring terminal device 1 of this modified example does not include the conductive member 40 and the third switching member 43.

[0084] Furthermore, in this modified example, the first switching member 41 is positioned between the equipment terminal 30 and the first grounding terminal 31, electrically connecting the equipment terminal 30 and the first grounding terminal 31 when in the closed state S1, and electrically disconnecting the equipment terminal 30 and the first grounding terminal 31 when in the open state S2.

[0085] In other words, when the first switching member 41 is tightened against the main body 10, the first bottom plate 30a of the equipment terminal 30 and the second bottom plate 31a of the first grounding terminal 31 each come into contact with the first switching member 41, and the equipment terminal 30 and the first grounding terminal 31 are electrically connected via the first switching member 41. Conversely, when the first switching member 41 is loosened from the main body 10, the first bottom plate 30a of the equipment terminal 30 and the second bottom plate 31a of the first grounding terminal 31 each separate from the first switching member 41, and the equipment terminal 30 and the first grounding terminal 31 are electrically disconnected.

[0086] Furthermore, in this modified example, the second opening / closing member 42 is positioned between the first grounding terminal 31 and the second grounding terminal 32, electrically connecting the first grounding terminal 31 and the second grounding terminal 32 when in the closed state S1, and electrically disconnecting the first grounding terminal 31 and the second grounding terminal 32 when in the open state S2.

[0087] In other words, when the second opening / closing member 42 is tightened against the main body 10, the second bottom plate 31a of the first grounding terminal 31 and the third bottom plate 32a of the second grounding terminal 32 each come into contact with the second opening / closing member 42, and the first grounding terminal 31 and the second grounding terminal 32 are electrically connected via the second opening / closing member 42. Conversely, when the second opening / closing member 42 is loosened from the main body 10, the second bottom plate 31a of the first grounding terminal 31 and the third bottom plate 32a of the second grounding terminal 32 each separate from the second opening / closing member 42, and the first grounding terminal 31 and the second grounding terminal 32 are electrically disconnected.

[0088] Furthermore, the fourth switching member 44 in this modified example is positioned between the second grounding terminal 32 and the third grounding terminal 33, electrically connecting the second grounding terminal 32 and the third grounding terminal 33 when in the closed state S1, and electrically disconnecting the second grounding terminal 32 and the third grounding terminal 33 when in the open state S2. In this modified example, the fourth switching member 44 is as described in the claim. 4 This corresponds to the "third opening / closing member".

[0089] In other words, when the fourth opening / closing member 44 is tightened against the main body 10, the third bottom plate 32a of the second grounding terminal 32 and the fourth bottom plate 33a of the third grounding terminal 33 each come into contact with the fourth opening / closing member 44, and the second grounding terminal 32 and the third grounding terminal 33 are electrically connected via the fourth opening / closing member 44. Conversely, when the fourth opening / closing member 44 is loosened from the main body 10, the third bottom plate 32a of the second grounding terminal 32 and the fourth bottom plate 33a of the third grounding terminal 33 each separate from the fourth opening / closing member 44, and the second grounding terminal 32 and the third grounding terminal 33 are electrically disconnected.

[0090] Next, we will describe the case in which the grounding resistance is measured using the grounding resistance measuring terminal device 1 of this modified example.

[0091] Figure 12 is a circuit diagram of the grounding resistance measuring terminal device 1 of Figure 11 when measuring the grounding resistance of the first grounding electrode 5. When measuring the grounding resistance of the first grounding electrode 5, the first switching member 41, the second switching member 42, and the fourth switching member 44 are opened from the closed state S1 to the open state S2 of the first switching member 41 and the second switching member 42. As a result, the first grounding terminal 31, the first grounding wire 5a, and the first grounding electrode 5 are electrically isolated from the equipment terminal 30, the second grounding terminal 32, and the third grounding terminal 33, and the grounding resistance of the first grounding electrode 5 can be measured.

[0092] Figure 13 is a circuit diagram of the grounding resistance measuring terminal device 1 of Figure 11 when measuring the grounding resistance of the second grounding electrode 6. When measuring the grounding resistance of the second grounding electrode 6, the first switching member 41, the second switching member 42, and the fourth switching member 44 are opened from the closed state S1 to the open state S2 of the second switching member 42 and the fourth switching member 44. As a result, the second grounding terminal 32, the second grounding wire 6a, and the second grounding electrode 6 are electrically isolated from the equipment terminal 30, the first grounding terminal 31, and the third grounding terminal 33, and the grounding resistance of the second grounding electrode 6 can be measured.

[0093] Figure 14 is a circuit diagram of the grounding resistance measuring terminal device 1 of Figure 11 when measuring the grounding resistance of the third grounding electrode 7. When measuring the grounding resistance of the third grounding electrode 7, the first switching member 41, the second switching member 42, and the fourth switching member 44 are opened from the closed state S1 to the open state S2. As a result, the third grounding terminal 33, the third grounding wire 7a, and the third grounding electrode 7 are electrically isolated from the equipment terminal 30, the first grounding terminal 31, and the second grounding terminal 32, and the grounding resistance of the third grounding electrode 7 can be measured.

[0094] Figure 15 is a circuit diagram of the grounding resistance measuring terminal device 1 of Figure 11 when measuring the combined grounding resistance of the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode 7. When measuring the combined grounding resistance of the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode 7, the first switching member 41 is opened from the closed state S1 of the first switching member 41, the second switching member 42, and the fourth switching member 44 to the open state S2. As a result, the first grounding terminal 31, the second grounding terminal 32, and the third grounding terminal 33 are electrically connected to each other but electrically disconnected from the equipment terminal 30. In other words, the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode 7 are electrically connected to each other but electrically disconnected from the electrical equipment 2. Therefore, the combined grounding resistance of the first grounding electrode 5, the second grounding electrode 6, and the third grounding electrode 7 can be measured.

[0095] Furthermore, if the third grounding wire 7a and the third grounding electrode 7 are not electrically connected to the third grounding terminal 33, the fourth switching member 44 may be in either the closed state S1 or the open state S2. Also, in this case, when measuring the combined grounding resistance of the first grounding electrode 5 and the second grounding electrode 6, the second switching member 42 is set to the closed state S1 and the first switching member 41 is set to the open state S2.

[0096] <Grounding Resistance Measurement Terminal Device Unit> Next, a ground resistance measurement terminal device unit 100 according to an embodiment of the present disclosure will be described. Figure 16 is a plan view of the ground resistance measurement terminal device unit 100 according to an embodiment of the present disclosure. Note that the cover portion 20 is not shown in Figure 16.

[0097] The ground resistance measurement terminal device unit 100 comprises two of the ground resistance measurement terminal devices 1 of the above embodiment. The ground resistance measurement terminal device unit 100 also further comprises a connecting member 50.

[0098] The connecting member 50 is a conductive linear member. The connecting member 50 is, for example, a conductive wire. The connecting member 50 electrically connects the third grounding terminal 33 of one of the two grounding resistance measuring terminal devices 1 to the equipment terminal 30 of the other grounding resistance measuring terminal device 1.

[0099] Hereinafter, one of the two ground resistance measurement terminal devices 1 will be referred to as the first ground resistance measurement terminal device 1α, and the reference numerals of the components of the first ground resistance measurement terminal device 1α will be described by adding the subscript "α" to the reference numerals of the components of the ground resistance measurement terminal device 1 in the above embodiment.

[0100] Furthermore, the other of the two ground resistance measurement terminal devices 1 will be referred to as the second ground resistance measurement terminal device 1β, and the reference numerals of the components of the second ground resistance measurement terminal device 1β will be described by adding the subscript "β" to the reference numerals of the components of the ground resistance measurement terminal device in the above embodiment.

[0101] In the first ground resistance measuring terminal device 1α, the first end of the connecting member 50 is positioned between the fourth bottom plate 33aα and the fourth pressing plate 33bα of the third ground terminal 33α. When the fourth mounting screw 33cα is tightened, the head of the fourth mounting screw 33cα presses against the fourth pressing plate 33bα, and the first end of the connecting member 50 is clamped between the fourth bottom plate 33aα and the fourth pressing plate 33bα. As a result, the third ground terminal 33α and the first end of the connecting member 50 are electrically connected.

[0102] Furthermore, in the second grounding resistance measuring terminal device 1β, the second end of the connecting member 50 is positioned between the first bottom plate 30aβ and the first pressing plate 30bβ of the equipment terminal 30. When the first mounting screw 30cβ is tightened, the head of the first mounting screw 30cβ presses against the first pressing plate 30bβ, and the second end of the connecting member 50 is clamped between the first bottom plate 30aβ and the first pressing plate 30bβ. As a result, the equipment terminal 30β and the second end of the connecting member 50 are electrically connected. Therefore, the third grounding terminal 33α of the first grounding resistance measuring terminal device 1α and the equipment terminal 30β of the second grounding resistance measuring terminal device 1β are electrically connected via the connecting member 50.

[0103] As described above, according to this embodiment, the ground resistance measurement terminal device unit 100 comprises a first ground resistance measurement terminal device 1α, a second ground resistance measurement terminal device 1β, and a connecting member 50 that electrically connects the first ground resistance measurement terminal device 1α and the second ground resistance measurement terminal device 1β. According to this, even when the first grounding electrode 5 and the second grounding electrode 6 are electrically connected to the first grounding resistance measuring terminal device 1α, grounding electrodes can be easily added to the first grounding terminal 31β, the second grounding terminal 32β, and the third grounding terminal 33β of the second grounding resistance measuring terminal device 1β.

[0104] Furthermore, additional grounding electrodes can be added by adding a grounding resistance measuring terminal device 1 that is electrically connected to any one of the first grounding terminal 31β, the second grounding terminal 32β, and the third grounding terminal 33β. Thus, the grounding resistance measuring terminal device unit 100 can easily accommodate additional grounding electrodes.

[0105] Furthermore, any one of the first grounding terminal 31β, second grounding terminal 32β, and third grounding terminal 33β of the second grounding resistance measuring terminal device 1β may be electrically connected to any one of the equipment terminal 30α, first grounding terminal 31α, second grounding terminal 32α, and third grounding terminal 33α of the first grounding resistance measuring terminal device 1α via the connecting member 50.

[0106] While embodiments of the earth resistance measurement terminal device and earth resistance measurement terminal device unit of this disclosure have been described above, the earth resistance measurement terminal device and earth resistance measurement terminal device unit of this disclosure are not limited to the examples shown in the embodiments and modifications of embodiments.

[0107] For example, the first mounting screw 30c, the second mounting screw 31c, the third mounting screw 32c, and the fourth mounting screw 33c may be fitted onto nuts (not shown) that are fixed to the main body 10.

[0108] Furthermore, the first opening / closing member 41, the second opening / closing member 42, the third opening / closing member 43, and the fourth opening / closing member 44 may be manual switches.

[0109] Furthermore, the grounding resistance measuring terminal device 1 according to the above embodiment and its modified form does not necessarily have to include a third grounding terminal 33 and a fourth switching member 44. [Explanation of Symbols]

[0110] 1 Earth resistance measurement terminal device 1α First ground resistance measuring terminal device 1β Second earth resistance measurement terminal device 2. Electrical equipment 5 1st ground electrode 5a 1st ground wire 6 2nd ground electrode 6a 2nd ground wire 30 Equipment terminal 31 1st ground terminal 32 2nd ground terminal 33 3rd ground terminal 40 Conductive material 41 First opening / closing member 42 Second opening / closing member 43 Third opening / closing member 44. Fourth opening / closing member 50 Connecting Members 100 Grounding Resistance Measurement Terminal Device Unit

Claims

1. Equipment terminals that are electrically connected to electrical equipment, A first grounding terminal electrically connected to the first grounding wire, A second grounding terminal electrically connected to the second grounding wire, Conductive material and A first switching member electrically connects the equipment terminal and the conductive member when in a closed state, and electrically disconnects the equipment terminal and the conductive member when in an open state, A second switching member electrically connects the conductive member and the second grounding terminal when in a closed state, and electrically disconnects the conductive member and the second grounding terminal when in an open state, The device includes a third switching member that electrically connects the conductive member and the first grounding terminal when in a closed state, and electrically disconnects the conductive member and the first grounding terminal when in an open state. Earth resistance measurement terminal device.

2. It further includes a main body that can be attached to a utility pole. The equipment terminal, the first grounding terminal, the second grounding terminal, the conductive member, the first switching member, the second switching member, and the third switching member are arranged on the upper surface of the main body. The ground resistance measuring terminal device according to claim 1.

3. Third grounding terminal and The device further includes a fourth switching member that electrically connects the conductive member and the third ground terminal when the device is closed, and electrically disconnects the conductive member and the third ground terminal when the device is open. The ground resistance measuring terminal device according to claim 1.

4. Equipment terminals that are electrically connected to electrical equipment, A first grounding terminal electrically connected to the first grounding wire, A second grounding terminal electrically connected to the second grounding wire, Third grounding terminal and A first switching member that electrically connects the equipment terminal and the first ground terminal when in a closed state, and electrically disconnects the equipment terminal and the first ground terminal when in an open state, A second switching member electrically connects the first grounding terminal and the second grounding terminal when in a closed state, and electrically disconnects the first grounding terminal and the second grounding terminal when in an open state, The device includes a third switching member that electrically connects the second grounding terminal and the third grounding terminal when in a closed state, and electrically disconnects the second grounding terminal and the third grounding terminal when in an open state. Earth resistance measurement terminal device.

5. The first opening / closing member is a screw member. A grounding resistance measuring terminal device according to any one of claims 1 to 4.

6. The device comprises two ground resistance measuring terminal devices as described in claim 3 or 4, The device further comprises a connecting member that electrically connects the third grounding terminal of one of the two grounding resistance measuring terminal devices to the equipment terminal of the other grounding resistance measuring terminal device. Grounding resistance measurement terminal device unit.

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