JP4012098B2 - Earth leakage breaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a leakage breaker that cuts off an electric circuit when a leakage or ground fault occurs in an AC circuit, and particularly relates to simplification of wiring and assembly inside the leakage circuit breaker.
[0002]
[Prior art]
In a conventional earth leakage breaker, when supplying power to the earth leakage detection circuit, the electrical connection parts are reduced and the power supply terminal of the earth leakage detection circuit unit is connected to the zero-phase current transformer as a configuration for facilitating the wiring work. There has been proposed a configuration in which a part of a primary conductor is pressed and contacted and power is supplied from the primary conductor to a leakage detection circuit (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP 2001-35343 A (summary, FIG. 1, FIG. 5, FIG. 8)
[0004]
[Problems to be solved by the invention]
A conventional earth leakage breaker has a structure in which an electrical connection is obtained by pressing a power supply terminal provided on a printed circuit board, which is an earth leakage detection circuit unit, against a primary conductor of a zero-phase current transformer. Therefore, in order to ensure the contact reliability of the power supply terminal and the primary conductor, it is necessary to manage the contact surface and the pressing force. In addition, since the zero-phase current transformer is arranged in the center and the printed circuit boards are arranged on the left and right sides thereof, the mounting efficiency of the printed circuit boards is poor, and electrical connection means between the left and right printed circuit boards is also required. There was a problem.
[0005]
The present invention has been made to solve such a problem, and easily and reliably electrically connect a part of the primary conductor of the printed circuit board and the zero-phase current transformer, and implement the printed circuit board. An object of the present invention is to obtain a leakage breaker that can increase the efficiency and easily connect the power supply circuit simultaneously with fixing the zero-phase current transformer.
[0006]
[Means for Solving the Problems]
An earth leakage circuit breaker according to the present invention includes a casing made of a synthetic resin material and a base, a power supply-side terminal fitting installed on one side of the casing and connected to a power supply-side main circuit circuit, and A load-side terminal fitting installed on the other side of the casing to which the load-side main circuit circuit is connected, and a main circuit disposed in the casing so that the current of the main circuit circuit flows through the both terminal fittings A conductor, a primary conductor for a zero-phase current transformer formed in a part of the main circuit conductor, and the primary conductor for the zero-phase current transformer pass through to detect a leakage current of the load-side main circuit circuit and output an output signal. A zero-phase current transformer unit, a printed circuit board equipped with a leakage detection circuit component for determining a leakage of the load-side main circuit circuit based on an output signal from the zero-phase current transformer unit, and the printed circuit board Printed circuit board held at a predetermined position in the housing In the earth leakage circuit breaker having a holding case and an interruption mechanism for interrupting the current flowing through the main circuit conductor in response to the discrimination operation of the earth leakage detection circuit component, the printed circuit board holding case is formed in a substantially L-shape. The zero-phase current transformer unit is formed in a shape that fits into the L-shaped space of the printed circuit board holding case, and the zero-phase current transformer unit is fitted into the printed circuit board holding case. This constitutes a leakage detection unit.
[0007]
Further, the zero-phase current transformer unit stabilizes the connection state by the connector with the leakage detection unit by incorporating an amplifier for amplifying the output signal of the zero-phase current transformer.
[0008]
Further, the control power supply terminal is directly mounted on the printed circuit board and connected to the control power supply of the leakage detection circuit component, and is formed to be exposed on the outer surface of the printed circuit board holding case. The circuit conductor and the primary conductor for the zero-phase current transformer are overlapped and screwed to obtain a control power source for the leakage detection circuit component from the main circuit conductor.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is an exploded perspective view showing a configuration of a leakage detection unit of a leakage breaker according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of the leakage breaker including the leakage detection unit of FIG. 3 to 9 are perspective views showing the assembly procedure of the leakage detection unit of FIG. In each drawing, auxiliary lines for assembling are described for easy understanding.
In FIG. 1, a printed circuit board 1 is mounted with a control power supply terminal 3 for connecting a control power supply of the leakage detection circuit component 2 together with a leakage detection circuit component 2 for determining leakage, and is formed of an insulating synthetic resin. The case 4 and the case 5 that also serves as the lid of the case 4 are housed in both cases and protected from contamination by a blocking gas or the like. Hereinafter, a case in which the case 4 and the case 5 are integrally combined will be described as a printed circuit board holding case 45.
[0010]
The thickness dimension B of the zero-phase current transformer unit 6 is configured to be substantially the same as the thickness dimension A of the printed circuit board holding case 45 so as to be fitted adjacent to the printed circuit board holding case 45. A zero-phase current transformer unit 6 is arranged. The signal of the zero-phase current transformer unit 6 is transmitted from the terminal 6a to the leakage detection circuit component 2 via the connector 7 provided on the printed circuit board 1. Further, in the zero-phase current transformer unit 6, the primary conductor 8 through which the main circuit current is passed passes through the through hole 6b of the zero-phase current transformer 6c (see FIGS. 8 and 9). A hole 8 a is provided at one end of the primary conductor 8. The hole 8 a is a hole of a main circuit conductor formed integrally with a load side terminal fitting 20 described later and a hole 3 a provided in the control power supply terminal 3. It is a hole for screwing together. In the first embodiment, the example of the load side terminal fitting 20 has been described as a main circuit conductor. However, when the power supply side and the load side of the earth leakage circuit breaker are reversely connected, the load side terminal fitting 20 is used. Becomes the power supply side terminal 20. Further, an overcurrent tripping portion 9 for detecting overcurrent is connected to the end of the primary conductor 8 opposite to the hole 8a. The printed circuit board holding case 45 is provided with a nut 10 for screwing the hole 8a of the primary conductor 8, the control power supply terminal 3, and the like, and the leakage detection unit 11 is constituted by these.
[0011]
In FIG. 2, the casing of the earth leakage circuit breaker is composed of a base 12 and a cover 13, both of which are made of a synthetic resin material having high insulating properties. The power supply side terminal fitting 14 is fixed to the base 12 and is electrically connected to the fixed contact 15 to energize the main circuit current. A movable contact 16 is provided so as to be opposed to and away from the fixed contact 15, and the fixed contact 15 and the movable contact 16 together with an arc extinguishing device 17 constituted by a plurality of arc extinguishing plates, etc. The shut-off mechanism (not shown) is configured. The handle 18 is connected to the movable contact 16 and is used for manually opening and closing the earth leakage breaker. The movable contact 16 is connected to the overcurrent tripping section 9 via a flexible conductor 19 or the like, and the main circuit current flows to the load side terminal fitting 20 via the primary conductor 8. Yes. The screw 21 is electrically connected by screwing the control power supply terminal 3 together with the primary conductor 8 and the load side terminal fitting 20.
[0012]
The earth leakage breaker includes an electromagnetic trip device 22 for tripping the earth leakage breaker when an earth leakage occurs in the main circuit circuit on the load side. Electrically connected. In the first embodiment, the sensitivity switching device 24 for switching the sensitivity of leakage detection and the test switch 25 for confirming the leakage operation are integrated with the electromagnetic trip device 22. Sensitivity switching signals and test signals from these devices or switches are also transmitted to the leakage detection unit 11 via the connector 23, and a sensitivity switching function and test function (not shown) in the leakage detection unit 11 (printed circuit board 1 in FIG. 13, the test resistor 6h and the tertiary winding 6g) of FIG. 14 are activated.
[0013]
Next, details and assembly procedure of the leakage detection unit 11 will be described with reference to FIGS. FIG. 3 shows a process of incorporating the printed circuit board 1 on which the leakage detection circuit component 2 and the control power supply terminal 3 are mounted into the case 4 whose inner dimension is slightly larger than the outer dimension of the printed circuit board 1. FIG. Here, the control power supply terminal 3 is soldered to a land provided on the printed circuit board 1 and can be soldered together with other electronic components by flow soldering. Reference numeral 1a denotes a connector, which will be described later.
[0014]
FIG. 4 is a diagram of a process of covering the case 4 in which the printed circuit board 1 is incorporated with the case 5. The case 5 is provided with a slit 5a into which the control power supply terminal 3 can be inserted at a position facing the control power supply terminal 3, and the case 4 and the case 5 are combined (state of the printed circuit board holding case 45). Thus, the portion of the hole 3a of the control power supply terminal 3 goes out of the case 5.
[0015]
5 and 6 show a process of bending the control power supply terminal 3 outside the case 5. FIG. 5 shows a lead wire 23 a connected to the connector 23. A connector (not shown) connected to the connector 1a (see FIGS. 3 and 4) of the printed circuit board 1 is provided at the end of the lead wire 23a. Further, a nut recess 5b is provided in the case 5 so that the nut 10 for screwing the control power terminal 3 can be fixed. After mounting the nut 10 in the nut recess 5b, the control power supply terminal 3 is bent at a right angle so that the hole 3a of the control power supply terminal 3 overlaps the screw hole of the nut 10 with the lower end of the slit 5a as a fulcrum. In FIG. 6, the arrow indicates the bending direction, and the control power supply terminal 3 after being bent is indicated by a broken line.
[0016]
From the above configuration and process, the control power supply terminal 3 is desired to have a material and shape that can be easily bent. For example, a tough pitch copper plate (C1100P of Japanese Industrial Standard JIS H3100) having a plate thickness of about 0.2 mm is suitable as the material of the control power supply terminal 3. That is, this material has less springiness and has a characteristic of being easily bent than a general copper plate. Further, it is effective to make the control power supply terminal 3 easy to bend by forming a small hole or notch at a position where the control power supply terminal 3 is bent.
[0017]
FIG. 7 is a view in which the primary conductor 8 passes through the zero-phase current transformer 6 c of the zero-phase current transformer unit 6. In this example, the primary conductor 8 is formed in a state of being bent at a right angle on the front side and the rear side of the zero-phase current transformer 6c before passing through the zero-phase current transformer 6c. Depending on the case, it may be bent after passing through the zero-phase current transformer 6c. Further, the primary conductor 8 is passed through the zero-phase current transformer 6c in a state where the overcurrent tripping portion 9 is coupled to the primary conductor 8, but after the primary conductor 8 is passed through the zero-phase current transformer 6c. The overcurrent tripping portion 9 may be coupled to the primary conductor 8.
[0018]
8 joins the unit having the outer periphery constituted by the printed circuit board holding case 45 shown in FIG. 6 and the unit centering on the zero-phase current transformer unit 6 through which the primary conductor 8 shown in FIG. 7 penetrates. It is explanatory drawing. In FIG. 8, the zero-phase current transformer unit 6 is attached to the circuit board holding case 45 along the sliding guide 26 provided in the circuit board holding case 45. At this time, the zero-phase current transformer unit 6 is slid along the insertion / removal direction of the terminal 6a provided on the zero-phase current transformer unit 6 and the connector 7 (see FIG. 1) provided on the mounting surface of the printed circuit board 1. The connector is connected by moving it.
FIG. 9 shows a completed drawing of the leakage detection unit 11.
[0019]
In the earth leakage circuit breaker configured as described above, when the load-side terminal fitting 20 and the primary conductor 8 attached to the base 12 are screwed together with the screw 21 and the nut 10 as shown in FIG. Since it is tightened, the control power supply is connected simultaneously with the connection of the load side terminal fitting 20 and the primary conductor 8. Therefore, the connection work of the control power supply is simplified, and the control power supply terminal 3 is firmly tightened together with the primary conductor 8 by the screw 21 and the nut 10 to improve the reliability of the electrical connection. Further, since the primary conductor 8 through which the main circuit current flows and the load-side terminal fitting 20 are in direct contact with each other, the electrical contactability is excellent as compared with the case where the control power supply terminal 3 is sandwiched between the primary conductor 8 and the load-side terminal fitting 20. . Further, the load side terminal fitting 20 is fixed to the base 12 in advance, and the load side terminal fitting 20, the primary conductor 8, the control power supply terminal 3, and the nut 10 are integrated as the leakage detection unit 11. The screw 21 is also used to fix the leakage detection unit 11 to the base 12.
[0020]
Further, making the primary conductor 8 and the load-side terminal metal fitting 20 as separate parts has the merit that the primary conductor 8 easily penetrates the through-hole 6b of the zero-phase current transformer 6c, as well as the primary conductor 8 and the load-side terminal metal fitting 20 In addition, there is an effect that materials having different thicknesses and materials can be selected. Further, the load-side terminal fitting 20 has an L-shaped surface 20a on the main surface of the zero-phase current transformer 6c, that is, the longitudinal direction of the leakage breaker (from the power-side terminal fitting 14 to the load-side terminal fitting 20). The length of the earth leakage breaker in the longitudinal direction can be shortened because it is connected to the primary conductor 8 having a connection portion in a plane perpendicular to the direction of the earth leakage breaker. Further, since the screw 21 is connected to the load-side terminal fitting 20 and the primary conductor 8 on the bottom side of the base 12 of the earth leakage circuit breaker than the surface 20b to which the external terminal of the load-side fitting 20 is attached, that is, Since the bottom side of the base 12 is an area where no parts or the like are originally arranged, it is possible to contribute to downsizing of the earth leakage circuit breaker and to have a preferable configuration such that a sufficient installation space can be secured when the screw 21 is attached. .
[0021]
Further, since the control power supply terminal 3 is directly soldered to a land provided on the printed circuit board 1, it is soldered together with electronic components constituting the leakage detection circuit component 2 in an automatic soldering process such as flow soldering (dip soldering). Man-hours are reduced due to the fact that Note that the control power terminal of the earth leakage breaker disclosed in Japanese Patent Laid-Open No. 2001-35343, which is cited as an example of a conventional earth leakage breaker, is directly soldered to the printed circuit board as in the present invention. In order to make electrical connection by contact pressure, the control power supply terminal becomes large because it is necessary to secure the contact area and strength of the control power supply terminal, and it tends to be difficult to solder in terms of heat capacity. In the first embodiment, since the connection is made with a sufficient tightening force by the screw 21, it is not necessary to enlarge the control power supply terminal 3 and the soldering workability is improved.
[0022]
Further, as shown in FIG. 1, the printed circuit board 1 is substantially L-shaped, and the position where the load side terminal fitting 20 and the primary conductor 8 face each other is set at the lower side of the printed circuit board 1 to control power. The terminal 3 is mounted, and the leakage detection circuit 2 is mounted on the remaining part of the printed circuit board 1, that is, the other side of the L-shape, so that one printed wiring board divided in the left and right in the conventional example is provided. It is summarized in. As a result, mounting efficiency is improved, and electrical connection between the left and right printed wiring boards is no longer necessary. At the same time, the zero-phase current transformer unit 6 is arranged in the empty space that occurs when the printed wiring board 1 is arranged in a rectangular space having two L-shaped sides as vertical and horizontal sides. Even in the zero-phase current transformer unit 6 in a state where 8 is assembled, the sliding movement from the lateral direction or the upward direction facilitates coupling with the printed wiring board 1 and improves the storage efficiency.
[0023]
Embodiment 2. FIG.
In the first embodiment, as shown in FIG. 1, the leakage detection unit 11 is provided with the two-pole control power supply terminal 3. However, as shown in FIG. Control power can be taken from all the main circuit circuits of the poles. That is, if the control power supply terminal 3 of the central pole is installed in the leakage detection unit 11 with the same configuration as the control power supply terminal 3 in the case of two poles, the control power can be taken from the main circuit circuit of all three poles.
This is because the conventional power leakage breaker obtains the control power from the left and right two of the three poles as is well known, but in this embodiment, the control power terminal 3 and the slit 5a through which it passes are added. Thus, it is possible to obtain a control power source from three poles as shown in the internal wiring diagram shown in FIG. 11 without changing the structure. Therefore, it is possible to prevent the loss of the leakage detection function at the time of phase loss.
[0024]
Embodiment 3 FIG.
As shown in FIG. 8, the printed circuit board 1 and the printed circuit board holding case 45 for storing the printed circuit board 1 are substantially L-shaped, and the zero-phase current transformer unit 6 can be fitted together by sliding from the side. It has a configuration. Accordingly, the zero-phase current transformer unit 6 and the printed circuit board are provided by outputting the signal of the zero-phase current transformer unit 6 to the terminal 6a and providing the connector 7 on the portion of the printed wiring board 1 facing the terminal 6a. The wire harness between 1 can be omitted, and the connection work can be simplified and the space can be saved.
[0025]
In addition, by providing a sliding guide 26 along the sliding direction of the zero-phase current transformer 6 in the cases 4 and 5 (printed circuit board holding case 45), the sliding movement of the zero-phase current transformer 6 is assisted. The terminal 6a and the connector 7 can be easily fitted, whereby the terminal 6a and the connector 7 can be reduced in size and pitch.
[0026]
Next, the zero phase current transformer unit 6 will be described in detail with reference to the block diagram of the zero phase current transformer unit in FIG. 12 and the internal connection diagram of the zero phase current transformer unit in FIG. An insulating resin case 6d is provided with a substrate 6e on which a zero-phase current transformer 6c, an amplifier 6f, a terminal 6a, and the like are mounted, and a test resistor 6h. In this state, the insulating resin case 6d is filled with an insulating resin such as an epoxy resin. It is fixed. FIG. 12 shows a state before a resin such as an epoxy resin is filled. Electrically, as shown in FIG. 13, power is supplied from the terminal 6a to the amplifier 6f that amplifies the output of the secondary winding 6k of the zero-phase current transformer 6c, and the amplified signal is output from the terminal 6a. Is output to the leakage detection circuit component 2. A test resistor 6h connected to the tertiary winding 6g of the zero-phase current transformer 6c is also connected to the terminal 6a.
[0027]
The zero-phase current transformer unit 6 configured as described above accommodates a part of the circuit (for example, the amplifier 6f) of the leakage detection circuit component 2 in a case 6g that covers the outline of the zero-phase current transformer 6c. By increasing the level of the signal output to 6a, the connection reliability between the terminal 6a and the connector 7 can be improved. This is because the secondary output of the zero-phase current transformer 6c is generally as small as several mV to several tens of mV, and if the signal level as it is flows through the terminal 6a and the connector 7, there is a risk of contact failure. Although measures such as applying gold plating to the terminal 6a and the connector 7 were necessary, the amplifier circuit 6f of the leakage detection circuit component 2 was substantially taken into the zero-phase current transformer unit 6 side, and the amplified signal was connected to the terminal 6a. By energizing the connector 7, for example, by setting the amplification factor of the amplifier 6 f to about 100 times, the signal level is changed from several hundred mV to several V, and the terminal 6 a and the connector 7 can be of a general specification. It becomes possible. Note that the external shape of the zero-phase current transformer unit 6 is increased by incorporating a part of the leakage detection circuit component 2 into the zero-phase current transformer unit 6 side. However, as shown in FIG. By effectively utilizing the space at the corner of the phase current transformer 6c and the storage space, the storage efficiency can be improved.
[0028]
Further, in the conventional earth leakage breaker, the sensitivity is switched by changing the resistance value of the sensitivity adjusting resistor connected to the output terminal of the secondary winding 6k of the zero-phase current transformer with a switch in the sensitivity switching device 24. However, in this embodiment, the output signal of the secondary winding 6k is directly input to the amplifier 6f, and the sensitivity is switched by changing the amplification factor of the amplifier 6f. The amplification factor control input terminal 6m is an input terminal for changing the amplification factor. For example, if an amplifier called VCA (Voltage Controlled Amplifier) is used as the amplifier 6f, the amplification factor control input terminal 6m is proportional to the voltage input to the amplification factor control input terminal 6m. Therefore, the sensitivity can be switched by inputting the sensitivity switching voltage supplied to the sensitivity switching device 24 to the amplification factor control input terminal 6m.
[0029]
By the way, although the above description has mainly described the 3-pole earth leakage breaker, it is needless to say that it can be utilized even with 2-pole or 4-pole earth leakage breakers.
[0030]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0031]
The primary conductor and main circuit connection terminal are directly screwed to the control power supply terminal mounted on the printed wiring board, which not only increases the reliability of the control power supply connection, but also simplifies the wiring work and wiring space. Therefore, the earth leakage circuit breaker can be downsized.
[0032]
Further, by adopting a structure in which the control power supply terminal is directly soldered and attached to the land of the printed wiring board, it is possible to perform soldering in the electronic component soldering process, and the number of assembling work can be reduced.
[0033]
The material and shape of the control power supply terminal shall be a material and shape that is less springy and can be easily deformed. After soldering to the land provided on the printed wiring board, the control power supply terminal is deformed into a predetermined shape. It becomes easy, and it is difficult for stress to be applied to the soldered portion, so that problems such as solder cracks can be prevented.
[0034]
In addition, since it is arranged so that at least one side of the printed wiring board faces the connection part of the main circuit connection terminal and the primary conductor of all the poles, any combination can be freely made by the control power supply terminal provided on the printed circuit board. Thus, it becomes possible to obtain a control power supply.
[0035]
Since the number of control power terminals is the same as the number of poles of the circuit breaker, the control power can be obtained from any pole, so that one pole is provided for a three-pole breaker and two is provided for a four-pole breaker. Even when the poles are out of phase, the leakage detection circuit can be operated, increasing safety.
[0036]
The shape of the printed circuit board is almost L-shaped, and a zero-phase current transformer is installed in the space that is created when the L-shaped printed wiring board is housed in a square space with the L-shaped sides as vertical and horizontal sides. By arranging, the space inside the circuit breaker can be used efficiently, so that the storage efficiency is improved and the circuit breaker can be downsized.
[0037]
The zero-phase current transformer unit is electrically connected by a pluggable connector provided on the printed wiring board, and the zero-phase current transformer unit slides only in the same direction as the connector insertion / removal direction in the case that houses the printed circuit board. By providing a guide that can be used, electrical connection between the printed circuit board and the zero-phase current transformer unit is simplified, and assembly is facilitated.
[0038]
Contains the zero-phase current transformer unit housed in the case with the zero-phase current transformer and an amplifier that is part of the leakage detection circuit component electrically connected, and the zero-phase current transformer unit and the remaining leakage detection circuit. By using a connector that can be electrically connected to and removed from the printed circuit board, the level of a signal flowing through the connector increases, so that the connection reliability of the connector is improved.
[0039]
Since the main circuit connection terminal is formed in an L shape and connected to the primary conductor and the primary conductor having a connecting portion on the surface perpendicular to the longitudinal direction of the earth leakage breaker, the longitudinal dimension of the earth leakage breaker is shortened. it can.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a leakage detection unit of a leakage breaker according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view showing an earth leakage circuit breaker.
FIG. 3 is a perspective view showing a method for assembling the leakage detection unit of the first embodiment.
4 is a perspective view showing a method for assembling a leakage detection unit according to Embodiment 1. FIG.
FIG. 5 is a perspective view showing a method for assembling the leakage detection unit of the first embodiment.
FIG. 6 is a perspective view showing a method for assembling the leakage detection unit of the first embodiment.
FIG. 7 is a perspective view showing a method for assembling the leakage detection unit of the first embodiment.
FIG. 8 is a perspective view showing a method for assembling the leakage detection unit of the first embodiment.
FIG. 9 is a perspective view showing a completed state of the leakage detection unit of the first embodiment.
FIG. 10 is an exploded perspective view showing a configuration of a leakage detection unit of a leakage breaker according to a second embodiment.
FIG. 11 is a circuit diagram showing internal wiring of an earth leakage breaker that is Embodiment 2 of the present invention.
12 is a schematic diagram showing a configuration of a zero-phase current transformer unit according to Embodiment 3. FIG.
FIG. 13 is an internal connection diagram of the zero-phase current transformer unit of FIG.
[Explanation of symbols]
1 Printed wiring board, 2 Leakage detection circuit, 3 Control power terminal,
4 Case, 5 Case, 6 Zero Phase Current Transformer, 7 Connector, 8 Primary Conductor,
9 Overcurrent tripping section, 11 Earth leakage detection unit, 12 Base, 13 Cover,
14 power supply side terminal fittings, 20 load side terminal fittings, 21 screws,
22 electromagnetic trip device, 23 connector, 24 sensitivity switching device,
25 test switches, 26 guides.

Claims (9)

A casing made of a synthetic resin material consisting of a base and a cover, a power supply side terminal fitting installed on one side of the casing and connected to a power supply main circuit circuit, and a load installed on the other side of the casing A load-side terminal fitting to which the side main circuit circuit is connected, a main circuit conductor disposed in the casing so that a current of the main circuit circuit flows through the both terminal fittings, and one of the main circuit conductors A zero-phase current transformer unit that is formed in a section, and a zero-phase current transformer unit through which the primary conductor for the zero-phase current transformer penetrates, detects a leakage current of the load-side main circuit circuit, and generates an output signal; A printed circuit board on which a leakage detection circuit component for determining leakage of the load-side main circuit circuit from an output signal from the zero-phase current transformer unit is mounted, and the printed circuit board is held at a predetermined position in the housing A printed circuit board holding case and the above leakage detection circuit An earth leakage circuit breaker having a breaker mechanism that cuts off a current flowing through the main circuit conductor in response to a component discrimination operation, wherein the printed circuit board holding case is substantially L-shaped, and the zero-phase current transformer The unit is formed in a shape that fits into the L-shaped space of the printed circuit board holding case, and the leakage detection unit is configured by fitting the zero-phase current transformer unit into the printed circuit board holding case. A ground fault circuit breaker. The zero-phase current transformer unit and the printed circuit board holding case holding the printed circuit board are electrically connected by a connector that can be inserted and removed, and the zero-phase current transformer or the printed circuit board holding case is inserted and removed from the case. A sliding guide in the same direction as the direction is provided, and the zero-phase current transformer unit is slid along the sliding guide of the printed circuit board holding case so that the connector can be inserted and removed. The earth leakage circuit breaker according to claim 1. 3. The earth leakage circuit breaker according to claim 1, wherein the zero-phase current transformer unit includes an amplifier for amplifying an output signal of the zero-phase current transformer. A control power supply terminal mounted directly on the printed circuit board and connected to the control power supply of the leakage detection circuit component, and formed to be exposed on the outer surface of the printed circuit board holding case; 4. A control power source for a leakage detection circuit component is obtained from a main circuit conductor by overlapping and screwing a circuit conductor and a primary conductor for a zero-phase current transformer. The earth leakage breaker described in the item. The load side terminal fitting is formed in an L shape so that a surface orthogonal to a surface to which the load side main circuit circuit is connected becomes a connection surface of the main circuit conductor, and the connection surface of the main circuit conductor has zero 5. The earth leakage circuit breaker according to claim 4, wherein one end of the primary conductor for phase current transformer and the control power supply terminal are overlapped and screwed together. The main circuit conductor, the primary conductor, and the control power supply terminal are screwed to each other on the bottom side of the base on the back side of the surface to which the load side main circuit circuit of the load side terminal fitting is connected. Item 5. The earth leakage circuit breaker according to item 5. 6. The earth leakage circuit breaker according to claim 5, wherein the control power supply terminal is directly soldered to a land provided on a printed circuit board. 8. The earth leakage circuit breaker according to claim 7, wherein the control power source terminal is formed of a copper plate having a small spring property and easily deformable, and is bent at a substantially right angle at a predetermined position after being soldered to the land. 9. The earth leakage circuit breaker according to claim 8, wherein the number of the control power supply terminals is equal to the number of poles of the earth leakage circuit breaker on the printed circuit board corresponding to the position of the main circuit circuit.

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