JPH10117429A - Non-tracking receptacle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-tracking receptacle which can prevent tracking fire in advance by detectingh leak current running at the early stage, caused by graphitizing, and shutting down a cable run (distribution line). SOLUTION: The receptacle is provided with a leak current detecting part 3 having a conductor disposed between receptacle blade insertion openings 4, 4', a shutting-down circuit 5 which detects current detected by the leak current detecting part 3 and shuts down a distribution run, a switching circuit where the shutting-down circuit 5 is connected between two lines of distribution lines L1, L2, a heating element H provided between the switching circuit and the distribution line, a temperature fuse Y which is serial-connected on the distribution line and blown off by heating the heating element H, and the gate G of the switching circuit is connected to the leak current detecting part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outlet for preventing tracking, and more particularly, to detecting a minute leakage current flowing between blade outlets of an outlet and cutting off an electric supply path at an initial stage of tracking. Non-tracking outlets that can be used.

[0002]

2. Description of the Related Art Fire caused by tracking caused by dust and moisture adhering to a small gap between a power outlet and a plug is increasing. When dust or moisture adheres to the gap, a discharge is generated in the gap, graphite is generated on the surface of the plug or outlet material, and a conductive path (track) is formed. This truck has a resistance value, generates heat, and leads to a fire. Unlike other fires, the fire caused by this tracking generates heat from the outlet and leads to a fire even if the electrical equipment connected to the outlet is not operating, and the wiring is interrupted until the fire spreads and the wiring is short-circuited. There was a problem that the vessel did not work.

In order to solve such a problem, conventionally, for example,
JP-A-8-45600, JP-A-8-883638
There is a tracking prevention tool disclosed in Japanese Patent Application Laid-Open Publication No. HEI 9-163, etc.

[0004] All of these conventional tracking preventive devices attempt to prevent tracking by making the shape around the plug case of the insertion plug or the blade insertion port of the outlet less likely to enter dust. .

[0005]

However, even if the shape of the plug casing and the shape of the outlet casing are difficult to enter dust as in the above-mentioned conventional apparatus, it is difficult to use such a place where there is a lot of water such as near a sink or a bath. In places with high humidity, such as near a place, moisture may penetrate, thereby causing tracking and graphitization. In this case, as the graphitization proceeds, tracking fire can no longer be prevented.

When the graphitization is in the initial stage, only a weak current flows due to its high insulation resistance.
Although the amount of Joule heat is small, when graphitization proceeds and a large current flows, the Joule heat increases in proportion to the square of the current, causing ignition. Therefore,
In the initial stage of graphitization, it is necessary to detect a weak leakage current and cut off the electric circuit.

[0007] In order to solve such a problem, the present invention detects a graphing at an early stage when a leakage current flows and cuts off an electric circuit (distribution line) to prevent a tracking fire. It is an object of the present invention to provide a non-tracking outlet that can be prevented.

[0008]

In order to achieve the above object, a non-tracking outlet according to the present invention is provided with a leakage current detector having a conductor disposed between blade outlets of the outlet. Features.

[0009] The leakage current detector can be connected to a ground terminal of an outlet.

Alternatively, there may be provided a cutoff circuit for detecting a current detected by the leakage current detection section and cutting off a distribution line.

The shutoff circuit is connected to a switching circuit connected between two lines of a distribution line, a heating element interposed between the switching circuit and the distribution line, and a heating element connected in series on the distribution line to connect the heating element to the switching element. A thermal fuse that blows due to heat generation,
And the gate of the switching circuit is connected to a leakage current detection unit.

Further, the shutoff circuit includes a switching circuit connected between one of the power supply lines on the secondary side of the earth leakage circuit breaker and the primary side of the earth leakage circuit breaker. It may be connected to a leakage current detection unit.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a first embodiment of a non-tracking outlet 1 according to the present invention. The leakage current detector 3 has a conductor disposed between the blade insertion ports 4 and 4 ′ of the plug formed in the outlet casing 2. For the conductor, for example, a bare copper wire can be used.
It is preferable to use an alloy material such as palladium silver in place of the bare copper wire.

FIG. 2 is a circuit diagram schematically showing the non-tracking outlet of FIG. The non-tracking outlet 1 uses a two-wire wired household outlet. The above-described leakage current detection unit 3 is connected to a gate terminal G of a triac T which constitutes a switching circuit 5 provided inside the outlet casing 2.

In the present embodiment, the leakage current detector 3 includes a diode D for preventing backflow at the gate terminal G of the triac T.
Connected through. The terminal T1 of the triac T, which is a component of the switching circuit 5, is connected to one of two lines L1 of a distribution line for supplying electricity, and the terminal T2
Is connected to another line L2. Terminal T2 and line L2
The heating element H is connected in series to the wiring connecting the. As the heating element H, for example, a resistor of 300 to 500 ohms can be used. The heating element H is connected to the line L2.
The temperature fuse Y is connected in series to the power supply side from the contact point with the fuse, so that the fuse Y contacts the heating element H, that is,
It is arranged so that the heat of the heating element H is transmitted.

When a track (conduction path) is generated between the blade insertion ports 4 and 4 'and graphite is generated, a leakage current flows from the leakage current detector 3 to the gate terminal G via the diode D. When the gate voltage of the triac T reaches a predetermined value, the trigger of the triac T turns on, and the terminal T1 and the terminal T2 become conductive. And
A current flows from the line L1 to the resistor constituting the heating element H through the terminals T1 and T2, and Joule heat is generated in the resistor. Due to the heat generated by the heating element H, the thermal fuse Y is cut off, and the line L2, which is an electricity supply path, is cut off. In this way, a cutoff circuit is configured.

In the above embodiment, a triac having a trigger turn-on current of 4 to 5 mA is used, and an extremely weak leak current can be detected to cut off the electric circuit. That is, it is possible to reliably cut off the wiring at the initial stage when tracking occurs.

Although the above embodiment has been described taking an example of an AC wiring, it is needless to say that the present invention can also be applied to a DC power supply. In this case, a thyristor or a power transistor is used for the switching circuit 5. be able to.

FIG. 3 is a circuit diagram schematically showing a second embodiment of the non-tracking outlet according to the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The features will be mainly described. This embodiment shows an example of an outlet that is wired in two lines by the earth leakage breaker 6.

The terminal T2 of the triac T is connected to the primary side of the earth leakage breaker 6 by a wiring L3. Therefore, the current detected by the leakage current detector 3 flows to the gate terminal G of the triac T, which is a component of the switching circuit 5, to turn on the trigger, and to turn on the terminals T1 and T2.
When the circuit becomes conductive and the circuit connected to the primary side of the earth leakage breaker 6 is configured, the earth leakage breaker 6 operates to cut off the wiring. Thus, the cutoff circuit is configured. As the earth leakage breaker, a normal type, for example, a high sensitivity type having a rated sensitivity current of 30 mA can be used.

According to the second embodiment, the heating element and the thermal fuse as in the first embodiment are not required, and the wiring can be cut off instantaneously.

FIG. 4 is a circuit diagram schematically showing a third embodiment of the non-tracking outlet according to the present invention.
An example in the case of wiring with three wires having a ground terminal E is shown. For the same components as in the above embodiment,
The same reference numerals are given and the description is omitted.

In this embodiment, the leakage current detector 3 only needs to be connected to the ground terminal E. In this case, the leakage current detected by the leakage current detector 3 is grounded through the ground terminal E, and the leakage breaker 6 is operated.

FIG. 5 shows a fourth embodiment of a non-tracking outlet according to the present invention, and is a plan view of an outlet for three-phase AC wiring.

The non-tracking casing 1 has blade insertion ports 4a and 4b containing non-grounded poles, a blade insertion port 4c containing a grounded electrode, and a ground terminal insertion port E '. As shown in the figure, the leakage current detector 3 has a metal wire arranged in a Y-shape so as to cross between the insertion ports 4a, 4b, 4c, and one end of the metal wire is connected to the ground. The terminal E 'is connected inside the outlet. In the case of three-phase alternating current, since it is necessary to cut off the three wires at the same time, the thermal fuse type described in the first embodiment cannot cope with it. It is necessary to construct additional wiring. The operation is the same as in the third embodiment, and a description thereof will be omitted.

FIG. 6 is an exploded bottom view showing a fifth embodiment of the non-tracking outlet according to the present invention.
Fig. 3 shows the device constructed inside by removing a bottom plate of an outlet.

In the figure, the outlet has the same basic structure as that of the well-known one, and a blade insertion electrode P to which wires L1 and L2 for supplying electricity are connected is provided in a casing 2a.
1 and P2 are fixedly provided. In the drawing, reference numeral 8 denotes a screw hole for stopping a bottom plate (not shown).

In this example, a partition plate 2 formed integrally with the casing 2a and partitioning between the blade insertion electrodes P1 and P2.
The conductor constituting the leakage current detection unit 3 is attached to the bottom surface of the b. The conductor is made of a metal wire, and is connected via a diode D to a gate electrode lead of a triac T constituting a switching circuit 5. The electrode lead T1 of the triac T is connected to the line L1, and the electrode lead T2 is connected to the line L2 via a resistor constituting the heating element H. The line L2 is connected to one blade insertion electrode P1 via the thermal fuse Y. The circuit configuration and its operation are the same as in the first embodiment.

The non-tracking outlet according to the fifth embodiment functions to detect a leakage current generated inside the outlet and to cut off the electric circuit. By combining such a non-tracking outlet of the fifth embodiment with the non-tracking outlet of the first to fourth embodiments, the tracking fire is more effectively prevented.

[0031]

As described above, since the leakage current is detected by the leakage current detecting section provided between the outlets of the outlets, the minute leakage current in the initial stage of graphitization can be detected. In addition, it is possible to prevent a tracking fire from occurring in advance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a first embodiment of a non-tracking outlet according to the present invention.

FIG. 2 is a circuit diagram schematically showing a circuit configuration of the embodiment of FIG. 1;

FIG. 3 is a circuit diagram schematically showing a non-tracking outlet according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram schematically showing a third embodiment of the non-tracking outlet according to the present invention.

FIG. 5 is a plan view showing an external appearance of a fourth embodiment of the non-tracking outlet according to the present invention.

FIG. 6 is an exploded bottom view of a fifth embodiment of the non-tracking outlet according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-tracking outlet 2 Outlet casing 3 Leakage current detector 4, 4 'Blade insertion port 5 Shutoff circuit 6 Earth leakage breaker E Ground terminal H Heating element Y Fuse

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02H 3/14 H02H 3/14

Claims (5)

[Claims] 1. A non-tracking outlet comprising a leakage current detector having a conductor disposed between blade outlets of the outlet. 2. The non-tracking outlet according to claim 1, wherein the leakage current detector is connected to a ground terminal of the outlet. 3. The non-tracking outlet according to claim 1, further comprising a cutoff circuit that detects a current detected by the leakage current detection unit and cuts off a power distribution path. 4. A switching circuit connected between two lines of a distribution line, a heating element interposed between the switching circuit and the distribution line, and the heat generation element connected in series on the distribution line. The non-tracking outlet according to claim 3, further comprising: a thermal fuse that is blown by heating of the element, wherein a gate of the switching circuit is connected to a leakage current detection unit. 5. The circuit according to claim 1, wherein the shutoff circuit comprises a switching circuit connected between one of the power supply lines on the secondary side of the earth leakage circuit breaker and the primary side of the earth leakage circuit breaker. 4. The non-tracking outlet according to claim 3, wherein the non-tracking outlet is connected to a leakage current detector.