JP5403776B1 - Detection device for connection failure etc. of indoor wiring, and determination method for connection failure etc. using the same - Google Patents

Abstract

In particular, it is possible to easily and easily determine a connection failure occurring in a distribution board, a branch portion, a connection terminal portion, or a connection portion of a wall outlet disposed in an indoor wiring circuit of an aged house.
[Solution]
The reference plug is connected to the distribution board side of the cable to be inspected. Plug the measurement plug into the wall outlet connected to the cable. From these plugs, the voltage drop for each core of the cable to be inspected is calculated. The difference between them is calculated from the voltage drop for each core wire. These differences are displayed so that the quality can be judged. Furthermore, connection sensitivity is improved by connecting a pseudo load and flowing a load current. In addition, work can be reduced by connecting a reference plug to a wall outlet connected to a child breaker that is different from the child breaker to which the F cable to be inspected is connected. Furthermore, two small-diameter measuring elements are arranged between the blades of the measuring plug so as to freely advance and retract. By measuring the insulation resistance of the plug contact part on the outlet surface by applying a voltage between the measuring elements, it is displayed so that the quality can be judged.
[Selection] Figure 7

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indoor wiring connection failure detection device and a connection failure determination method using the same, and more particularly, a wiring connection failure that causes a fire in a place where it is difficult to notice in daily life, for example, a wall outlet Detecting and judging wiring connection failures in connection parts in boxes and branching parts in the ceiling, etc., or suitable indoor wiring used to detect and judge insulation failures on plug contact surfaces of wall outlets The present invention relates to a connection failure detection device and a connection failure determination method using the same. Note that terms used in sentences and drawings may be abbreviated as appropriate.

1. Status of electrical fires According to the statistics of the Tokyo Fire Department in FY2011, electrical fires accounted for about 20% of the total number of fires, and in recent years the ratio has been increasing. The number of electric appliances generated by household appliances is the largest, followed by wall outlets, plugs, and cooking heaters. Of these, the causes of fires in electric heaters and cooking heaters are often improper handling, such as forgetting to switch off or igniting flammable materials.
On the other hand, the cause of a fire in a wiring device such as a wall outlet or a plug is due to abnormal overheating inside the device or a tracking phenomenon of the wall outlet plug connection, which occurs from a place that is difficult to notice in everyday life. There is a feature.

2. Ignition from wiring equipment Refrigerators and washing machines are often used as they are for more than 10 years after plugs are inserted into wall outlets. When vibration or temperature changes are applied to a wall outlet for a long period of time, deformation of the plug blade or outlet receptacle, oxidation of the metal surface, loosening of the connection wires inside the appliance, etc. will occur, increasing the electrical resistance and reducing the conduction performance. It may become defective. A wiring device having a markedly increased electrical resistance generates abnormal heat with normal product use current, and causes ignition.

  In addition, when used for a long time, a large amount of dust and dirt adhere to the gap between the wall outlet and the plug. When moisture accumulates in such a gap, the insulation of the instrument surface is lowered, and creeping discharge between the electrodes called a tracking phenomenon occurs. When the discharge is repeated, the insulator on the surface starts to carbonize and eventually becomes short-circuited (short-circuited) and ignites. The tracking phenomenon occurs regardless of whether the user is at home, away from home, day or night. For this reason, there are many cases where discovery is delayed and burnt down.

3. Current fire prevention method First, as a precautionary measure performed by the user, read the instruction manual carefully before using the appliance, and use it correctly. Next, there are discoloration and heat generation inspection of wiring devices such as wall outlets and plugs, and cleaning of the gap between the wall outlet and the plug. In addition, regular inspections conducted by electric power companies include household electrical leakage inspection and insulation measurement. An electrical leakage breaker is obliged to be installed on the distribution board at home, and electricity is automatically cut off when an electrical leakage occurs.

4). Fire Prevention Method Disclosed in Patent Literature Patent Literature 1 discloses a “connection failure detection device” capable of detecting a connection failure in a connection portion of an electric wire in an initial stage.
This device has a configuration in which voltage detection terminals made up of voltage sensors provided at both ends of a connection portion existing in a wire line are connected to terminals of a connection failure detection device, respectively. A characteristic voltage waveform generated at the time of discharging is stored in the connection failure detection device, and this is compared with the detected measurement voltage waveform to determine whether the connection is good or bad.

Patent Document 2 discloses “a wire connection failure detection circuit and circuit breaker”, and Patent Document 3 discloses a “connection failure detection circuit of an electric circuit connection portion”.
In these disclosed technologies, a sensor circuit for detecting a voltage waveform is connected to each electric circuit, and a waveform obtained from each sensor, that is, a specific voltage waveform generated at the time of poor connection is used as an information source. The waveform that has been preliminarily stored and stored is compared and calculated to determine whether the connection state is good or bad.

JP 2001-343416 A JP2009-145083 JP 2008-305664 A

1. Problems with the current fire prevention methods a. The increase in the size of household appliances and the increase in the size of the wall outlets make the area around the wall outlet dense, making it difficult to inspect and clean wiring equipment.
In addition, wall outlets are always energized and cannot be removed like plugs, making inspection and cleaning difficult.
b. Even if discoloration or overheating is found in the inspection, it is a state after abnormal heat generation has occurred and does not provide reliable fire prevention.
c. Even if there is a connection failure on the wall outlet side, if the current consumption of the electrical product is small, it will not generate heat and will not be found. Wall outlet appliances are often used as they are for decades, and there is a risk of lapse with ignition factors.
d. A poor connection of wiring or a poor insulation on the surface does not result in a poor insulation between the equipment and the earth or a leakage to the earth. For this reason, it is difficult to detect by the conventional leakage inspection, and the leakage breaker does not operate even in the case of overheating, and it is impossible to prevent fire reliably.

2. Problems of the fire prevention method disclosed in the above patent document The technique disclosed in Patent Document 1 is mainly intended to detect a contact failure of the contact mechanism inside the breaker, and the spike-like voltage waveform generated at that time Pay attention. Therefore, it is necessary to put sensors and detection devices in the surroundings of the breaker side in advance, and this cannot be applied to existing distribution boards for general households. New distribution boards or modified distribution boards There is a problem that must be exchanged.
In addition, there is a problem that a voltage waveform necessary for the determination cannot be obtained in a small current or no-current state, or the determination cannot be made when the spike-like waveform output is not obtained.

There are also problems with Patent Document 2 and Patent Document 3. That is, in the circuit configuration, even if there is a connection failure in the connection part, the sensor circuit does not operate unless a current exceeding a certain level flows, and detection is impossible. Furthermore, a sensor circuit must be arranged for each electric circuit connection portion where it is desired to detect a connection failure. However, in the indoor wiring of a general house, there are many electric circuit connection parts in concealed places such as the back of the ceiling and the back of the wall, and the installation to them becomes very complicated and complicated, which is practically impossible.
Furthermore, when it is desired to detect a defect in the connection portion of the cable connected to the wall outlet, it is necessary to connect the voltage detection line to the cable side and the wall outlet side, but this connection is actually impossible. For this reason, it is difficult for the disclosed invention of Patent Document 2 to detect a connection failure in the wall outlet portion.

  The present invention has been made paying attention to the above-mentioned problems, and in particular, a connection generated in a distribution board, a branch part, a connection terminal part, or a connection part of a wall outlet, which is arranged in an indoor wiring circuit of an aged house. It is an object of the present invention to make it possible to easily and easily determine a defect or an insulation defect occurring on the wall outlet surface.

In order to achieve the above object, an indoor wiring connection failure detection device (hereinafter referred to as “the present device”) according to the present invention is a target wiring for connection failure inspection in an indoor wiring wired with two or three core wires. Connecting means for connecting each core wire to both ends of the length; voltage measuring means for measuring a voltage drop amount for each core wire between the target wiring lengths through each connecting means; and for each core wire wherein the difference voltage detecting means for comparing the voltage drop amount detecting the Saryou from the voltage measuring means, and display means for displaying the results and quality determination from Saryou issued該検, that consisted It is said.

The operation of the device of the present application configured as described above is as follows.
Each core wire of a cable for indoor wiring (VVF cable, commonly referred to as F cable) usually consisting of two or three cores is manufactured according to the standard and has substantially the same conduction resistance value. Based on this assumption, when there is a poor connection portion in the electrical circuit for each core wire of the wiring length specified as the target of the connection failure inspection, the resistance value increases due to this, and a voltage drop correspondingly occurs.
The voltage drop is measured by voltage measuring means connected to each core wire, and the difference is detected by the difference voltage detecting means. Then, the amount of voltage drop for each core wire is compared to determine the difference, and based on this, the quality is determined, and the result is displayed on the display means.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, load means connected to the connection means connected to any one end side of the target wiring length is further provided.
When there is no connection of a load device (for example, connection of an electric appliance) in the electric circuit of the target wiring, no current flows. In this no-current state, no voltage drop occurs. This load means allows a load current for measurement to flow through the connection, thereby generating a voltage drop for measurement.

According to a third aspect of the present invention, either or both of the two connecting means connected to both ends of the target wiring length measure the voltage drop using an outlet provided indoors.
By using an outlet as a connection means connected to the power source side (distribution panel side) of the target wiring length, measurement work efficiency and safety can be remarkably improved within a range that does not affect measurement accuracy.

At the time of this voltage detection, only a current of about several tens mA for measurement flows through the core wire of the connecting means. Therefore, the voltage drop due to this is less than 1% of the voltage drop to be measured and can be ignored.
Therefore, even if the connection means is connected to an outlet connected to a different child breaker, such as the outlet of the next room, such as the outlet that is the object of measurement at that time, the original side The voltage can be acquired accurately. If it carries out like this, the length of the electric wire which connects an apparatus main body and a connection means can be shortened, and workability | operativity will improve.

The method of claim 4 uses the indoor wiring connection failure detection device according to claim 1, 2 or 3, and the voltage for each core wire is connected by connecting means connected to both ends of the target wiring length. It is characterized in that the presence of a connection failure is determined by measuring the amount of drop, determining the quality based on the measured difference in voltage drop, and displaying the result . The operation is the same as that of the indoor wiring connection failure detection device according to claim 1, 2 or 3.

According to the method of claim 5, when the target wiring is in a no-current state, a load current is caused to flow by a load means connected to any of the connection means, and a voltage drop amount for each core wire is detected and It is characterized by measuring the voltage drop difference. The operation is the same as that of the indoor wiring connection failure detection device according to claim 1, 2 or 3.
Further, in the method of claim 6, the length of the wiring to be inspected is specified between the different outlets to which the wires of different paths branched from the distribution board are connected, and the connecting means configured as plugs is fitted to each outlet. It is characterized by measuring. The operation is the same as that of the indoor wiring connection failure detection device according to claim 1, 2 or 3.

1. Effectiveness as a device a. To date, there is no device that can detect a connection failure in a ceiling back wiring, a wall outlet back wiring, or a concealed connection portion that is energized. The device of the present application can detect defective connection wiring that causes abnormal heat generation from the wall outlet appliance insertion port to the connection part on the back of the outlet to the cable behind the ceiling to the distribution board breaker connection part.
In addition, the device of the present application can also detect an insulation failure on the surface of the wall outlet device that causes a tracking phenomenon.
b. When measuring the internal continuity performance and surface insulation on the general principle without using the device of this application, load devices, ammeters, voltmeters, insulation meters, intermittent and switching switches, etc., and complicated wiring that connects them Is required. For this reason, work efficiency is bad and practicability is low. In the device of the present application, each measurement detection function and determination display function necessary for diagnosis are efficiently incorporated, and the utility is high.
c. The device of the present application is, for example, 8 kg in weight, can be further reduced in weight, and is compact. The operation and handling of the equipment is simple and does not require advanced technology. One person can detect the cause of electric fire in wall outlet wiring.
d. Positioning and fixing the contact for insulation measurement in the center of the measurement plug makes positioning and fixing easy and safe.
e. The device of the present application performs internal conduction performance and surface insulation performance measurement with a common measurement plug SP. If each performance is measured continuously, it takes about 5 seconds. For example, all the wall outlets in a house, for example, 30 to 60, can be diagnosed in a short time.
f. The apparatus of the present application can be applied to measurement of wiring devices such as a 200V wall outlet in addition to a 100V wall outlet.

2. Effectiveness from the viewpoint of fire prevention a. Conventional prevention is mainly based on visual and tactile senses such as discoloration and fever. The device of the present application diagnoses the surface insulation performance and internal conduction performance of wall outlet appliances by electrical measurement. The present apparatus can detect an abnormality at an early stage before overheating or ignition. For this reason, it is possible to prevent an electrical fire from a wall outlet or a ceiling branch branch.
b. Connection failure including cable wiring from the breaker of the distribution board to the wall outlet can be detected. Cable wiring is branched and connected to the wall for each room behind the ceiling. Since it is possible to detect abnormal heat generation parts, etc., which are difficult to detect in the past, it is possible to prevent fires from occurring behind the ceiling.
c. If excessive force or dirt is applied to the wiring or wall outlet due to an earthquake or water damage, it is necessary to confirm the continuity of the wall outlet and indoor wiring and the insulation performance of the surface for a large number of residences to prevent fire. is there. Since the apparatus of the present application can perform measurement work in a short time, confirmation work for a large number of residences can be performed in a short time.
d. The device of the present application can also diagnose other than a house. For example, many wall outlets are used for important buildings such as office buildings, factories, temples, shrines, and museums. If it is possible to detect a wall outlet wiring connection failure or surface insulation failure at an early stage by the device of the present application, it is possible to prevent electrical fires in these buildings and facilities.

It is a front view which shows a wall socket outlet and a plug, and a perspective view which shows the plug for measurement and measuring element of embodiment. It is a block diagram which shows the circuit structure at the time of measuring the insulation resistance of a wall socket. It is a connection diagram which shows the example of the indoor wiring from an electric energy meter to a wall outlet. It is a table | surface which shows the example of the top view which shows the external appearance of a 2-wire VVF cable, and its conductor resistance. It is a connection diagram which shows the example of the connection location in the indoor wiring from a distribution board to a wall outlet. It is a block diagram which shows the circuit structure at the time of measuring the voltage drop of each core wire of F cable when flowing load current, for example, 6A. A reference plug is connected to a wall outlet that is supplied from a distribution board breaker B that is different from the distribution board breaker (child breaker) A that supplies power to the wall outlet to be diagnosed. It is a connection diagram which shows the circuit structure at the time of considering and measuring the voltage drop of each core wire of F cable. It is a connection diagram for demonstrating how the appearance of the voltage drop to each wall outlet (ii)-(f) changes with the difference (1) (2) of the occurrence location of a connection failure. It is a block diagram which shows the circuit structure for measuring the voltage drop at the time of applying a resistive load. It is a block diagram which shows the basic control sequence of the example embodiment apparatus. It is a block diagram which shows the procedure of the outlet surface insulation resistance measurement of the example embodiment apparatus. It is a block diagram which shows the procedure of the 100V power supply voltage drop measurement of the example apparatus. It is a block diagram which shows the procedure of the instrument internal conduction performance measurement of the embodiment apparatus. It is a front view which shows the external appearance of the embodiment apparatus. It is a rear view which shows the external appearance of the embodiment apparatus. It is a table | surface which shows the general house measurement result made into the model. It is a top view which shows arrangement | positioning etc. of the wall outlet of each room of the model | house which used as a model. It is a connection diagram which shows the example of 100 / 200V single layer 3 wire type power distribution. It is a front view which shows the example of wiring of a distribution board, and each protection device. It is a connection diagram which shows the path | route of the electric current (broken line) at the time of B class grounding and an electric shock. It is a connection diagram which shows the example of an insulation measurement and a leakage current (broken line) measurement. It is a connection diagram which shows the example of the insulation fall of the outlet surface. An example of connection failure is shown. (A) is a connection diagram showing an example in which there is a connection failure at a connection point in B and heat is generated. (B) is a connection diagram showing an example of F cable wiring and connection points on the back of the ceiling. is there. FIG. 6 is a connection diagram illustrating an example of a resistance value or the like related to a connection failure for explaining a method of finding a connection failure wiring. There is resistance due to poor connection at the connection part of the black line, and when this causes a predetermined current to flow, a difference in voltage drop occurs between the black line side and the white line side to detect a connection failure. It is a layout for explaining this. It is a wave form diagram which compares and compares the voltage drop waveform of each line when the current for measurement changes at the time of black line measurement and white line measurement. Difference voltage detection by simultaneous subtraction is shown, (A) is a waveform diagram showing a case where there is a connection failure 0.1Ω on the black line side, and (B) is a waveform diagram showing a case where there is no connection failure on the black line side. It is a connection diagram which shows the example (1) of the application range of invention of patent document 1, and the example (2) of the application range of this invention. It is a circuit diagram which shows the example of a limit of the sensor action | operation of invention of patent document 2. FIG.

  Next, a specific embodiment ES of the present invention will be described. In addition, about the member displayed in one figure like wall outlet CW, in order to make a figure legible, the code | symbol is attached | subjected about some of them.

1. Approach to solving the problem To prevent an electrical fire from the wiring device, it is not enough for the user to discolor the device, check for heat, and clean it. For all wall outlets CW in the house, it is necessary to measure the internal continuity performance and the insulation performance of the surface CS by an electrical method, and to find an abnormal instrument whose performance has deteriorated at an early stage. .

  The indoor wiring of a modern house uses a high-quality cable of JIS standard in which two or more wires are assembled, branches from the distribution board DB behind the ceiling, and is wired to the wall outlet CW. The shape and dimensions of the wall outlet CW are standardized and common. Using these features, if there is a device that can easily detect abnormal equipment by measuring the continuity performance of the wall outlet wiring and the insulation performance of the surface CS while being energized, an electrical fire from the wall outlet CW side can be prevented.

2. Basic structure of device ES (1) Measurement function of device ES a. Insulation resistance measurement of wall outlet surface CS The insulation performance of the wall outlet surface CS is measured, and it is diagnosed whether there is insulation deterioration due to conductive dirt DT (FIG. 22) or tracking phenomenon. Display of the measurement result display of the insulation performance and the determination of pass / fail by comparison with the determination reference value.
b. Internal conduction voltage drop difference measurement of wall outlet CW Measure the conduction performance from the outlet of wall outlet CW to the back side connection part-ceiling back wiring-distribution board breaker B and diagnose whether there is a connection failure. The measurement result display and the display capable of determining pass / fail by comparing with the reference value are displayed.
c. 100V power supply voltage drop measurement of wall outlet Measures the power supply voltage at the time of no load and load of the outlet of the wall outlet CW, and displays the voltage drop of the 100V power supply so that it can be judged as good or bad.
Thereby, the voltage supply performance including the power supply side of the distribution board DB can be confirmed together with the measurement result of the internal conduction voltage drop difference.

(2) Evaluation method of instrument insulation resistance See Fig. 1 a. When dust or dirt DT (FIG. 22) adheres to the gap GP (FIG. 22) between the wall outlet and the plug, and moisture accumulates there, the insulation is lowered and eventually the tracking phenomenon discharge occurs. The insulation performance degradation occurs on the surface CF where the wall outlet contacts the plug. The measurement point TP of the insulation performance is set to the center of the wall outlet surface outlet that is the center of the surface CF that the plug contacts.
b. The center of this wall outlet is close to the 100V charging part. Therefore, in order to safely contact the measuring element for insulation measurement, two metal measuring elements SE are arranged in the center of the measuring plug SP so as to be able to advance and retract. When the measurement plug SP is inserted into the wall outlet CW, the measuring element SE is simultaneously contacted and fixed at the center position of the insertion port, and the measurement can be performed safely.

(3) Method of measuring the surface insulation resistance of the outlet outlet See Fig. 2 a. After contacting the measuring plug SE with the measuring position of the wall outlet CW, a DC voltage is applied between the measuring plugs SE, and the voltage of the device-side resistance generated by the flowing current is compared with the reference voltage, allowing pass / fail judgment To display.
b. As an example, the surface insulation resistance on the wall outlet CW side is 1 MΩ, and the device side resistance is 0.1 MΩ.
When the DC voltage is 11 V, the current is 11 V ÷ 1.1 MΩ = 10 μA.
The voltage generated in the device-side resistor is 0.1 MΩ × 10 μA = 1.0V.

(4) Evaluation method of internal conduction voltage drop difference a. The wiring from the distribution board DB to the wall outlet CW at home is as shown in FIG. In a modern house, a JIS standard cable FC as shown in FIG. 4 is used for wiring from the breaker B to the wall outlet CW. Two (or three) electric wires are incorporated in the cable. The cable FC is connected from the distribution board breaker B to the wall outlet CW through the ceiling. As a characteristic of the cable wiring, the inner two wires (black and white) to the wall outlet CW have the same wire thickness and the same wire length, and the conduction resistance values are almost equal.
b. Overheating due to poor connection occurs when there is a poor connection inside the wall outlet appliance, as well as defective connections such as the arrows in FIG. Abnormal heat generation occurs at the portion where the conduction resistance increases due to poor connection, and the temperature rises when a heat amount close to 10 W is concentrated. The cable wiring length from the distribution board breaker B to the wall outlet CW is about 10 to 30 m, but the conduction resistance value is very low, and normally the black and white two lines are almost the same value. However, when there is a connection failure, the conduction resistance value on the defective line side greatly increases. In the case of overheating, the resistance increase is about 0.1Ω or more, and it is possible to detect a defect based on a resistance value difference. (50m cable conduction resistance value 0.28Ω, 2-wire conduction resistance difference 0.01Ω or less)
c. A power failure is required to measure the difference in conduction resistance due to poor connection on one side with a precision resistance meter, and workability is poor. Therefore, since the two wires from the breaker B to the wall outlet CW are generally the same conduction resistance value, it is noted that the voltage drop of each of the two wires becomes the same value when a load current is passed. That is, when there is a connection failure, the voltage drop value of the connection failure side electrical line becomes large. A constant load current is passed through the wall outlet CW in the energized state to measure the voltage drop value of each of the two wires. If the difference between the two wire voltage drop values is abnormally large, it can be determined that there is a connection failure.
Although the probability is very low, there is a connection failure in both lines, and when the increased conduction resistance value is the same value in both lines, there is no difference in voltage drop between the two lines, and the defect cannot be detected. There may be cases.

(5) Measuring method of internal conduction voltage drop difference See Fig. 6 a. As an example, in the left electric circuit (1)-(2)-(3)-(4) and the right electric circuit (5)-(6)-(7)-(8) from the breaker B to the device ES, the conduction resistance is Suppose that 0.15Ω each, poor connection occurs at left side A circuit point A, and resistance increases by 0.10Ω. Note that the above (1), (2), etc. are represented by circled numbers in the figure. The same applies to the description of other parts of the present specification.
b. The measurement plug SP is inserted into the wall outlet CW, and the voltage measurement reference plug BP (crocodile clip CC) is connected to the breaker B side. Using a resistive load built in the device ES side, a measuring AC current 6A is passed through the wall outlet CW. Measure the AC voltage drop between the right circuit (5)-(8) and the AC voltage drop between the left circuits (1)-(4) at 6A.
Right side 0.15Ω × 6 A = 0.9V
Left side (0.15 + 0.10) Ω × 6 A = 1.5V
Detect voltage drop difference of 0.9V on the right side and 1.5V on the left side.
1.5V-0.9V = 0.6V
c. The case where the difference voltage 0.6V is equal to or higher than the reference voltage (0.4V) is determined to be defective, and the case where the difference voltage is less than that is determined to be good.
(0.4V × 6A = 2.4W, when the defective connection part generates heat of 2.4W or more at 6A)
d. By connecting the reference plug BP to the load side terminal of the breaker B, it is possible to detect a connection failure including the plug connection portion of the wall outlet device, the connection portion of the device and the cable, and the cable wiring connection portion CP of the ceiling.
e. See FIG. 7 In order to facilitate the connection work of the reference plug BP for voltage measurement, the measurement is performed by connecting the reference plug BP to the wall outlet CW connected to the breaker B instead of the load side terminal of the breaker A. The measurement range includes up to the breaker A side, but the workability of connecting the reference plug BP is good and practical. The current for voltage measurement flowing through the reference plug BP is very small. If the current of the outlet circuit on the breaker B side is small, the load side terminal on the breaker A side is used as a reference without being affected by the circuit on the B side. It is possible to measure the voltage drop that does not change.

(6) Evaluation method of 100V power supply voltage drop See FIG. 8 a. An abnormal power supply voltage drop at the wall outlet is generated not only when there is a significant connection failure in the wiring on the wall outlet side, but also when there is a significant connection failure in the distribution board breaker B or in the power supply side wiring. As an example, when there is a significant connection failure only at (1) point, only the wall outlet (in) is judged to be defective by the internal conduction voltage drop difference, and the power supply voltage drop is increased only in the wall outlet (in).
However, if there is a connection failure only at point (2), (i) to (f) all wall outlets will not be judged as defective in internal conduction voltage drop, but all power supply voltage drops will be large. When there is a significant connection failure inside the distribution board DB, measuring the power supply voltage drop at each wall outlet CW makes it easy to determine the cause and identify a defective breaker inside the distribution board DB.
b. Measure the 100V voltage at the outlet before and after flowing the load current 6A to the wall outlet CW, and determine the power supply voltage drop value at each wall outlet CW from the difference between before and after. Together with the results of the wall outlet internal conduction voltage drop difference (ii) to (f), it can be confirmed whether there is a significant connection failure on the power supply side lead-in wire or distribution board DB side.

(7) 100V power supply voltage drop measurement method See FIG. 9 a. A 6 A resistive load LD and power supply voltage measurement circuits BL1 to BL4 are built in the device ES side. The measurement plug SP is inserted, and the power supply voltage before flowing the load current is measured.
As an example (102V)
Next, the power supply voltage when the load current 6A flows is measured.
(97V)
Measurement result of power supply voltage drop, power supply voltage drop
102V-97V = 5V.

3. Block Configuration of Each Operation of Apparatus ES (1) Basic Control Sequence This sequence is as shown in FIG. I think that this content can be understood mainly from the descriptions of “(2) Operation method of the device ES” and “(3) Judgment criteria” in “5. Therefore, explanation here is omitted.
(2) Outlet outlet insulation measurement sequence This sequence is as shown in FIG. I think that this content can also be understood from the description of the same part as above. The description here is omitted.
(3) 100V power supply voltage drop measurement This sequence is as shown in FIG. I think that this content can also be understood from the description of the same part as above. The description here is omitted.
(4) Instrument internal conduction performance measurement This sequence is as shown in FIG. I think that this content can also be understood from the description of the same part as above. The description here is omitted.

4). Appearance of Device ES FIG. 14 shows the front of the device ES, and FIG. 15 shows the back of the device ES. It is thought that the function of each part can be understood mainly from the description of “(1) Description of appearance of device ES” in “5. Therefore, explanation here is omitted. In this embodiment, the width is 40 cm, the height is 24 cm, the depth is 26 cm, and the weight is 8 kg.

5. Description of handling of detection device ES (1) Description of appearance of device ES See FIGS. 14 and 15 a. Plug for measurement SP: A wall outlet to be measured, which is directly connected to a wall outlet connected to the distribution board breaker A in FIG. A contact SE for insulation measurement is provided in the center.
b. Reference plug BP ... For measuring internal voltage drop difference, connect to wall outlet connected to distribution board breaker B (Fig. 7) different from distribution board breaker A (Figure 7) connected to wall outlet to be measured .
c. Alligator clip CC: When there is only one child breaker B, it is directly connected to the load side of the child breaker B.
d. Power switch SW: Turns on the connection of the measurement plug SP. In addition to turning off, the control power supply of the detection device ES is turned on. Turn off.
e. Reset switch RS: Stops the control sequence being measured. LED result display and OK. The NG display is also canceled.
f. Continuous measurement switch CE ・ ・ ・ Surface insulation → Power supply voltage drop → Continuous measurement in the order of outlet voltage drop difference.
g. Polarity changeover switch PS: The polarities of the reference plug BP and the measurement plug SP are matched in order to measure the voltage drop between the same phases.
h. 6 vertical LEDs LE6 ... Displays the measurement results of surface insulation, power supply voltage drop, and outlet internal voltage drop in 6 levels (from the top, 2 red, 2 yellow, 2 green).
i. Three horizontal LEDs LE3... For each measurement item, BUSY (small diameter green), measurement result good OK (normal diameter green), and measurement result defect NG (red) are displayed.
j. Independent measurement switch IS: When each switch is pressed without using a continuous measurement switch, the displayed item is measured independently.
k. Built-in buzzer (not shown): Sounds when the polarity of the reference plug BP and the measurement plug SP does not match, or when the judgment result is poor.

(2) Operation method of apparatus ES a. Place the detection device ES near the wall outlet CW to be measured. Unplug all plugs PG in use at peripheral outlet CW at 100 W or more, or turn off the power switch. Insert the measurement plug SP all the way into the wall outlet CW for diagnosing.
b. Using an electric drum or extension cord, the wall outlet CW supplied with power from another breaker B (FIG. 7), which is different from the breaker A (FIG. 7) supplying the wall outlet CW to be measured, Insert the reference plug BP.
c. When there is only one child breaker B, the alligator clip CC is attached to the reference plug BP, and this alligator clip CC is attached to the load side terminal of the child breaker B. Since this is charged to 100V, care should be taken when installing so that the alligator CC does not slip and short during measurement.
d. Turn on the power switch SW. If the polarity of the measurement plug SP does not match the polarity of the reference plug BP, a buzzer (not shown) sounds. If the polarity does not match and the buzzer sounds, the polarity switch PS is operated to the opposite side to stop the buzzer.
The voltage drop is measured, for example, between the terminals (1) and (4) in FIG. 6 and between the terminals (5) and (8). At this time, depending on how the plugs SP and BP are inserted, the relationship between these terminals may be incorrect. In such a case, in each voltage measuring means VS in FIG. 6, the normal measurement voltage that is 1 V or less is close to 100 V in the normal state.
In such a case, the control means (not shown) built in the device ES determines that the polarity is opposite, and sounds the built-in buzzer.
e. Pressing the continuous measurement switch CE starts 3 items of continuous measurement. First, the surface insulation is measured in about 1 second, then the 100 V power supply voltage drop is measured in about 2 seconds, and the outlet internal voltage drop is measured in about 1 second. The whole measurement can be done in about 5 seconds.
f. BUSY is displayed during measurement, and OK or NG is displayed after measurement. For each measurement item, the measurement results are displayed in LED levels in six stages. A buzzer sounds when a defect is judged by comparing with the judgment criteria set inside.
g. When any single switch IS is pressed, each item of surface insulation, power supply voltage drop, and outlet voltage drop is measured individually. If any single switch IS is pressed with the operation display of three items remaining after continuous measurement, only that item is measured again.
h. When the reset switch RS is pressed after the measurement is completed, the six-level display of the measurement result and the OK / NG display are turned off. When the reset switch RS is pressed during measurement, the measurement operation inside the apparatus ES is immediately stopped and the initial state before measurement is restored.

(3) Criteria (in the case of the embodiment)
a. The insulation performance of the surface at the wall outlet plugging center is, for example, 2 MΩ or less as an insulation failure.
b. The 100V power supply voltage drop at the time of 6A load at the wall outlet outlet is, for example, 8V or more being defective. When there is this defect, if there is no abnormality in the voltage drop difference at the wall outlet CW, it is presumed that there is a conduction abnormality in the distribution board DB or the lead-in wire.
c. The difference in the two-wire voltage drop due to the deterioration of the internal conduction performance is, for example, 0.4 V or more at 6 A load current as defective.

(4) Precautions for use a. In order to increase the measurement accuracy, it is preferable to remove or stop the plug PG from the wall outlet CW for an electric product in use at 100 W or more.
b. In the apparatus ES of the embodiment, each measurement switch must be connected unless the reference plug BP is connected to the load side of the distribution board breaker A (FIG. 7) or to the wall outlet CW connected to another distribution board breaker B (FIG. 7). Even if CE or IS is pressed, it does not operate. In such a case, since the input of the voltage measuring means VS of FIG. 6 becomes zero, the connection state of the reference plug BP is determined based on this.
c. When the reference plug BP is inserted into the wall outlet CW in a single-phase three-wire system, the wall outlet CW that is 100 V in the same phase is selected so that the measurement voltage does not become 200 V, and the reference plug BP is connected thereto. If it is 200V, the buzzer will sound even if the polarity is switched.

7). Measurement results by the detection device ES a. An example of the measurement result in a general house is shown in FIG. Each wall outlet position at this time is shown as FIG. In addition, in each figure after the second column from the top of FIG. 17, “A” to “D” attached to the end of the title display are the wall outlets CW of the room, and the respective child breakers in the upper right figure. It represents that it is connected to “A” to “D”. The measurement results in FIG. 16 include the display of the detection device ES at each wall outlet position, the measured value of the 100 V power supply voltage drop before and after the 6 A load current is applied, and the left and right lines from the distribution board DB to the wall outlet CW. Includes measured values of internal conduction voltage drop.
b. The measurement results of the wall outlet internal conduction voltage drop in ordinary houses were all displayed in the range of 0 to 0.2V. The measured values of the internal conduction voltage drop on the left and right lines are a minimum of 0.30V and a maximum of 1.01V. In terms of 6A, this corresponds to a length of 2.0 mm cable 9 m and 30 m. The difference voltage between the left line and the right line in a good wiring device is about 0.01 to 0.03 V, which is a considerably small value with respect to the defect determination level of 0.4 V or more.
8). Other a. The connection of the reference plug BP, but not from the load side terminal of the supply breaker A (FIG. 7) to the wall outlet to be measured, is supplied from another child breaker B (FIG. 7) using the extension cord 20m. The measurement was performed by inserting the reference plug BP into the wall outlet CW of the room.
b. The apparatus ES according to the embodiment normally judged a dummy insulation failure (1 MΩ) or connection failure (0.1Ω) as a failure.
c. Although it overlaps, the note at the top of FIG. 16 is also written here.
1. “Measurement points (1), (2), (3),...” Represent plug-in positions (1), (2), (3),.
2. The “reference position” indicates the wall outlet position where the reference plug BP for voltage measurement is connected (plug insertion).
3. “Display of detection device” indicates which of the LEDs on the front surface of the detection device ES at that time is illuminated.
4). “100V power supply voltage drop” represents an actually measured voltage drop of 100V before and after the 6A load current is applied.
5. “Left line (right line) internal voltage drop” represents an actually measured value of the internal voltage drop on the left line (right line) when a 6 A load current is applied.
6). The “right and left line differential voltage” in the rightmost column indicates the difference between the left line internal voltage drop and the right line internal voltage drop.

9. In addition, it supplements below about the electrical wiring of a home. The purpose of this supplement is to explain the detection method based on the drawing of the power line, the switchboard protection switch, the current at the time of electric shock, the wiring configuration, the electric fire, the voltage drop difference, etc. in addition to the explanation so far. It is to deepen the understanding of the invention.
Supplements will be made on the following items.
(1) Supply system of low-voltage lamp line An example of supplying a 100V / 200V lamp from the power company 6600V transformer side to the house.
(2) Distribution board DB wiring and protection device Protection function of the lead-in / lead-out line and various switches (breakers) in the home distribution board DB.
(3) Class B grounding and current during electric shock Ground wiring and electric current path during electric shock due to Class B grounding work on the transformer low voltage side.
(4) Insulation measurement and leakage current measurement Insulation measurement and leakage current measurement method for indoor wiring by periodic inspection of electric power companies.
(5) Insulation failure of outlet surface CS Insulation failure of outlet surface CS and detection range in periodic inspection by electric power company.
(6) Heat generation of wiring due to poor connection Abnormal heat generation due to indoor wiring to the wall outlet CW and conduction resistance due to poor connection.
(7) How to find connection failure wiring Increase in conduction resistance due to connection failure and characteristics of conduction resistance in cable wiring.
(8) Failure detection by voltage drop difference Measurement of voltage drop value of two wires and detection of conduction failure by voltage difference between voltage drop values.
(9) Differential voltage detection by simultaneous subtraction Differential voltage detection method and error countermeasure by simultaneous subtraction of 2-wire voltage drop value waveform.

(1) Supplying system for household power lines (1) There are 100V single-phase two-wire systems and 100V / 200V single-phase three-wire systems for supplying low-voltage piezoelectric cables from electric power companies. FIG. 18 shows an example of connection between the power company transformer connection and the lighting lead-in wiring to the house according to each supply method.
(2) Although there are many 100V single-phase two-wire systems for supplying low-voltage piezoelectric wires in old houses, houses with large contracted capacity and houses using 200V home appliances are 100V / 200V single-phase three-wire systems. A 100V single-phase two-wire house is supplied with two wires R (T) and N, and a 100V / 200V single-phase three-wire house is supplied with three wires R, N, and T.

(2) Distribution Panel DB Wiring and Protection Device FIG. 19 shows an example of distribution panel DB wiring and protection device. In the figure,
(1) is a contract switch (breaker) MB that determines the contract capacity with the electric power company. If the usage exceeds the contracted current, this switch automatically determines that it is overcurrent, and the switch breaks and causes a power failure.
(2) is a leakage breaker LB that prevents electric shock and fire due to leakage. When the operating rating is 30 mA, when a leakage or electric shock that causes a current of 30 mA or more to flow in the ground occurs, the switch is instantaneously cut off to protect it. In addition to 30 mA, when a rating of 40 A is displayed, it is also used as an overcurrent breaker.
(3) is a child breaker B for overcurrent protection and has a rating of 20A. If the current exceeds the allowable current of the wiring device due to excessive use of home appliances or a short circuit accident of the wiring, etc., it will cause a fire accident due to overheating. Therefore, the current is automatically cut off to protect the wiring device by making a power failure. F wiring with a built-in 2-wire is often used for indoor wiring, but it is always routed to the place of use via the child breaker B.
(4) is a 100V lamp lead-in line, which is connected from the power company side to the distribution board DB of the house via a power meter. The connection cable is a thick cable that can withstand the current rating of the contract breaker MB.
(5) is a cable used for indoor wiring from child breaker B, and there are many wire diameters of 2.0 mm F cable. Each electric device used in the house is always supplied with wiring from the child breaker B, and is protected in case of overcurrent. For the child breaker 20A, the allowable current of the 2.0 mm F cable wire is 24 A, and there is a current margin.
(6) An over-current protection child breaker B cannot protect a fire accident caused by overheating of the wiring due to a poor connection of the wiring equipment or an ignition of the equipment due to the discharge of the tracking phenomenon. In addition, since there is no electric leakage to the ground, the electric leakage breaker LB is not cut off and cannot be protected by the distribution board DB. The reason why the wiring will ignite even if it is not an overcurrent and the reason why it will not cause a ground leakage will be explained in the following sections.

(3) Class B grounding and current during electric shock Class B grounding and current during electric shock are shown in FIG.
(1) According to the technical standards for electrical equipment, the secondary N terminal of the transformer is grounded to the ground as a measure to prevent the risk of voltage rise on the low-voltage winding side in the event of a mixed contact between the high-voltage winding and the low-voltage winding. It is considered to be seed grounding. Therefore, the N terminal on the secondary side of the transformer is usually at the same potential as the ground, and the ground voltage on the N line side is 0V.
(2) When the R line (T line) side that is not on the N line side is touched with bare hands, the voltage to ground is 100 V, so an electric shock is caused at 100 V. The electric current at the time of electric shock (broken arrow) circulates with hand → body → ground → B-type ground wire → transformer. If you touch the grounded N-line side, you will not get an electric shock because the ground voltage of the N-line is 0V.
(3) Here, it is assumed that 100W illumination is turned on at two locations, and a human touches the R line side of the right illumination with his bare hand and is electrocuted at 50 mA. The figure shows the flow of an electric shock (leakage) current of 50 mA (0.05 A) and an illumination current of 1.0 A (solid arrow).
(4) When an electric shock (leakage) that causes electricity to flow to the ground occurs, the earth leakage breaker LB in the distribution board is the difference current (R side 2.05 A-N side 2.00 A = 0.05 A) Detect and operate automatically. The earth leakage breaker LB has an earth leakage detection coil CL surrounding the R line and the N line, and operates when a difference current is detected. After detecting an electric shock or electric leakage current, it operates instantly and stops power to prevent electric shock deaths and electric leakage fire accidents.
(5) The tracking phenomenon that occurs due to the insulation decrease of the contact surface CF between the outlet and the plug is a current discharge that flows along the insulator creepage surface between the 100V electrodes. If attention is paid only to the discharge phenomenon, it is a current that leaks through the surface of the insulator, but it is not expressed as a leakage because no leakage current flows to the ground. In this case, the earth leakage breaker LB does not operate.
(6) In relation to electric shock, when boots with insulating properties are used, there is no electric shock even if the R wire is touched with bare hands. However, if the left hand touches the N line with a bare hand while touching the R line with the right hand, it is a matter of course that an electric shock will occur. Also in this case, since the electric current flows from the R line to the right hand → through the human body → the left hand → the N line, the leakage breaker LB does not operate.

(4) Insulation measurement and leakage current measurement FIG. 21 shows insulation measurement and leakage current measurement. That is,
(1) There is insulation measurement in the regular inspection of electric power companies. For the measurement, the contract breaker MB of the distribution board is opened, the measurement electrode of the insulation meter is applied to the load side line of the child breaker B, one electrode is connected to the ground, and a voltage of about 100 V DC is applied. The direct current flowing in the ground is converted into a resistance value, and a value less than 0.1 MΩ is treated as a failure. Wiring at the time of new construction and wiring maintaining good insulation performance have insulation performance of about 10 to 20 MΩ.
(2) There is also a leakage check in the periodic inspection of electric power companies. While the distribution board breaker B is inserted, 100V is applied to the indoor electrical equipment. Clamp the cable (2-wire) on the distribution board power supply side with the tip of the clamp meter and measure the leakage current of 100V. The clamp meter can measure the differential current between the R line and the N line with an accuracy of 0.01 mA. If the current measured by the clamp meter exceeds 1 mA, it becomes defective. 100V ÷ 0.1MΩ = 1mA
(3) Leakage of just over 1mA and insulation failure close to 0.1MΩ are not enough for the earth leakage breaker LB (30mA) to operate, but over time, there is a risk of major leakage or electric shock accidents, so refurbishment is necessary. It becomes.
(4) In general, regular inspections by electric power companies measure the insulation between the whole indoor wiring and the ground and the leakage current flowing between the ground, including household electrical appliances that are plugged into the wall outlet, such as TVs and kotatsu. . Therefore, it is impossible to detect an abnormality caused by a decrease in insulation performance between the 100 V electrodes caused by contamination on the outlet surface. Also, abnormalities due to poor indoor cable wiring connections or poor connection at the outlet plug cannot be detected.
(5) It is impossible to measure the insulation between the R line and the N line supplied from the distribution board DB to each electric device in a house use state. This is because remote control ceiling lighting or a device being inserted enters between the R line and the N line, and insulation between the R line and the N line cannot be secured. If all devices such as outlet connection devices and ceiling lighting load equipment used in the house are removed, insulation measurement between the R line and the N line can be performed, but in reality, it is difficult to remove all of them and measurement is impossible.

(5) Decrease in insulation on the outlet surface CS (1) There is a tracking phenomenon as a cause of electric fire. As shown in FIG. 22, when dirt accumulates on the surface of the wall outlet CW or the plug PG, or when dust DT adheres to the gap GP between the wall outlet and the plug, As a result, the insulating property is remarkably lowered, and the surface of the instrument insulator is creepingly discharged between the electrodes. Eventually, when the surface is carbonized, a short ignition occurs. The same symbol “DT” is used for “dirt” and “dust”.
(2) In daily life, in the wiring apparatus from the lead-in wire to the wall outlet CW, the 100V charging part is not directly exposed. The wall outlet surface CS of a kitchen or a bathroom is likely to be contaminated with food splashes and salt-containing soils in daily life, and the outlet surface CS is often stained like A. However, if the plug PG is not inserted as shown in FIG. 22 (A), the electrode is due to the fact that there is little moisture even if dirt DT adheres to it and there is a distance to the charging part electrode in the wall outlet. There is no significant decrease in insulation, and creeping discharge is still difficult to occur.
(3) On the other hand, in the wall outlet into which the plug PG is inserted as shown in FIG. 22B, dust and moisture tend to accumulate in the gap GP between the wall outlet and the plug. Further, when the plug PG is inserted into the wall outlet CW, the charged portion of the plug blade PP is exposed on the surface and the distance from the dirty surface (DT) is lost. The exterior material of the wall outlet CW and the plug PG is originally an insulator, but if the dirt DT contains moisture, it becomes a conductive electrolyte, which significantly reduces the insulation, and between the charged parts of the plug blade PP. A weak creeping discharge occurs. The discharge carbonizes the insulator surface and proceeds to a large discharge, resulting in a fire accident.
(4) Discharge or ignition due to the tracking phenomenon is a discharge phenomenon that occurs due to a decrease in insulation performance between the 100 V electrodes, and is not a leakage current flowing to the ground or a decrease in insulation performance from the ground. Therefore, it cannot be detected by insulation measurement or electric leakage inspection by periodic inspection of electric power companies. Since the earth leakage breaker LB does not operate, ignition cannot be prevented.
(5) As a method of preventing an electric fire due to the tracking phenomenon, there is cleaning of the connecting portion CP and visual confirmation. However, it is difficult to judge the appearance of the surface-contaminated surface CS of the wall outlet including salty soils and surface insulation degradation due to past discharge. When the plug PG is inserted into the wall outlet CW with reduced insulation for a long period of time, a tracking phenomenon is likely to occur. In such a case, an electrical fire can be prevented if the surface insulation measurement of the wall outlet CW in the house is performed and a defective device can be detected.
(6) There are usually about 15 to 30 wall outlets CW in the house, and 30 to 60 measurement points in the case of the plug-in two-port type. An apparatus that can detect and judge in a short time is desirable to see all of the presence or absence of poor connection or poor surface insulation.

(6) Heat generation of wiring due to poor connection (1) The conduction resistance of the F cable 20m having a strand diameter of 2.0 mm is 0.10Ω. Prepare two sets of 20m lines A and B, connect cables A and B in the middle, and calculate the heat generation when a 6A load current flows as shown in FIG. (Note 1) When B, B and C are in good connection, there is no new increase in conduction resistance due to connection.
Cable A heat generation = Black wire side heat generation + White wire side heat generation Cable A heat generation = 6A x 6A x 0.10Ω + 6A x 6A x 0.10Ω
Heat generation of cable A = 3.6W + 3.6W
= 7.2W.
The heat generated only by the cable A black wire is 3.6 W, but because it is 20 m long, the heat generated by a unit length of 0.1 m is 0.02 W. The amount of heat generated per 0.1 m is small, and heat dissipation is easy, so the black wire in the cable does not become hot.
(2) When there is a connection failure, the conduction resistance of the connection failure portion increases, and heat generation concentrates on the failure portion, resulting in abnormal overheating. Assuming that the conduction resistance of 0.10Ω has increased due to the black line connection failure in ↓, calculate heat generation.
Heat generation in the black line poor connection portion = 6A × 6A × 0.10Ω = 3.6W If the heat generation length of the black line connection failure portion is 0.1 m, the heat generation with a unit length of 0.1 m is 3.6 W. The unit heat generation with a good connection cable is 180 times larger than the unit length of 0.02 W, making it difficult to dissipate heat and the black wire becomes hot.
(3) When the electric wire reaches a high temperature, the surface of the copper wire is rapidly oxidized, and the conduction resistance is further increased, resulting in a vicious cycle of heat generation. If the wire coating gets hot, it will be damaged by heat and will eventually ignite. If the resistance increase due to poor connection is 1Ω, the current becomes about 10 W at a current of about 3 A, resulting in a high temperature. During this abnormal overheating, each breaker MB, LB, B of the distribution board does not perform a protective operation.
(4) FIG. 23B shows an example of cable wiring from the child breaker B to the wall outlet CW in the house. The poor connection occurs at the connection point CP of the electric wire or the insertion point of the wall outlet and the plug PG. These points at which connection failure may occur in the wiring from the child breaker B are indicated by arrows →. Arrows → dots are connection / insertion in the wall outlet, connection CP on the ceiling, and connection in the distribution board. Because it is a concealed part, it is difficult to detect even if there is abnormal overheating.

(7) Method for Finding Connection Failure Wiring (1) Here, as shown in FIG. 24, it is assumed that connection failure occurs at the black line connection point of cable A and cable B, and the conduction resistance increases by 0.10Ω.
(2) Since the abnormal overheating of the wire is caused by heat generation due to an increase in the conduction resistance due to poor connection, there may be a case where the poor connection can be found by a discoloration by appearance or a method using a tentacle. However, this method can be applied only when a large current flows through the electric wire and there is already a discoloration or a high-temperature part and the electric wire can be directly seen and touched. When the operating current is 2 to 3 A, the heat generated by the poor connection 0.10Ω is 1 W or less, and cannot be found by the appearance or the method using the tentacles.
(3) As one of the methods for detecting a connection failure, it can be considered to measure the conduction resistance of 0.20Ω in the initial stage of the black line and compare the current conduction resistance of 0.30Ω. If an increase of 0.10Ω can be confirmed by measurement, the presence of a connection failure can be confirmed. However, in order to accurately grasp the resistance increase of 0.10Ω, a measuring method having an accuracy of 0.01Ω is required. Moreover, the resistance of the copper wire rises by about 0.4% at a temperature of 1 degree, and the electric wire with a resistance of 0.20Ω rises to 25 ° by 0.22Ω. That is, the resistance value changes depending on the outside air temperature or the heat generation of the cable body. For this reason, when this method is used, it is necessary to consider temperature changes.
(4) The number of cables used in the house is large and the wiring length is also different. Therefore, it is difficult and impractical to pre-measure and record the initial conduction resistance value of the black line and the white line for each wiring in order to find out the occurrence of a connection failure later.
(5) Therefore, as a solution, focus on the black line CCB and white line CCW of the cable. Detection of connection failure requires the initial conduction resistance value, but the initial conduction resistance of the black (white) line can be substituted with the white (black) line of the same cable. Domestic cables are of high quality, and the copper wire diameter difference between the black line CCB and the white line CCW of the same cable is within 0.02 mm. In the cable wiring from the distribution board DB to the wall outlet CW, the lengths of the black line CCB and the white line CCW are the same, and the difference in the conductor resistance value in the same cable of the black line CCB and the white line CCW is usually 0.01Ω or less. . Therefore, it can be regarded as the same conduction resistance value. Replacement of white (black) line eliminates the need for initial conductor resistance measurement. Moreover, since the black line CCB and the white line CCW change in the same manner as the temperature change of the conduction resistance due to the outside air temperature or heat generation of the cable body in use, it is not necessary to consider the temperature change.
(6) That is, for example, in order to see the connection failure on the black line CCB side, the conduction resistance value 0.20Ω on the white line CCW side is measured as the initial conduction resistance, and then the conduction resistance value 0.30Ω on the black line CCB side is measured. To do. And what is necessary is just to confirm the increase presence or absence of conduction resistance from both measured values. However, the white line CCW has the same connection failure, and cannot be found when the same conduction resistance value is obtained. However, the probability that such a situation will occur is very low.
(7) Moreover, in order to actually measure the conduction resistance values of the black line CCB and the white line CCW from the child breaker B to the wall outlet CW with a precision resistance meter, a power failure of the measurement target wiring is required. Furthermore, the method of measuring the resistance value by connecting the measurement line of the precision resistance meter to the electrode of the breaker terminal B and the wall outlet CW every time takes much time for the measurement work, and the work efficiency is poor. Moreover, if the connection of the measurement line for measurement itself is insufficient, the measurement error increases. After all, it is difficult in terms of time to measure all the indoor cables wired to the wall outlet CW by this method.
(8) In order to increase the work efficiency, it is necessary to devise a measurement method that replaces the conduction resistance measurement of the black line and the white line without interrupting the indoor 100V power supply and a detection method that can obtain the measurement result in a short time. This will be described in the following section.

(8) Failure detection due to voltage drop difference (1) The conduction resistance value can be obtained by measuring the voltage drop value of the electric wire in a state where a constant current is passed through the electric wire. Therefore, for example, as shown in FIG. 25, 6A is passed through the resistance load using an AC 100V power supply, and the same current 6A flows through the black line CCB and the white line CCW.
In this state, the voltage drop A between the black line side I-ha is measured, and then the voltage drop between the white line side I-ha BB is measured. The ratio of the voltage drop value between the black line CCB and the white line CCW is the same as the ratio of the conduction resistance value between the black line CCB and the white line CCW. Obtaining the difference voltage from the voltage drop between the black line CCB and the white line CCW is the same as obtaining the difference resistance of the conduction resistance value due to poor contact.
Black line voltage drop A = 6A x 0.3Ω = 1.8 V
White line voltage drop BB = 6A × 0.2Ω = 1.2 V
From the voltage drop value difference 0.6 V between the black line CCB and the white line CCW, it can be confirmed that there is a connection failure of 0.10Ω on the black line CCB side.
(2) However, this measurement is valid when the load current is constant (6 A) as shown in FIG. If the load current is constant, the waveforms A and B at the time of measuring the black line CCB and the waveforms AA and BB at the time of measuring the white line CCW are not changed, and the black line CCB and the white line CCW are different even when the measurement timing is different. This is because the voltage drop is measured correctly.
(3) On the other hand, if the power supply side voltage or load fluctuates during measurement and there is a current change as shown in FIG. If the load current at the time of black line CCB measurement was 6A, but it became 7A at the time of white line CCW measurement, waveforms A and AA, B and BB at the time of each measurement would not be the same, black line CCB This is because each voltage drop is not correctly measured for the white line CCW.
In particular,
Black line voltage drop A = 6A x 0.3Ω = 1.8 V
White line voltage drop BB = 7A x 0.2Ω = 1.4 V
Difference in voltage drop between black line and white line 0.4 V
The connection failure on the black line CCB side cannot be confirmed.
(4) To prevent the influence of current change, it is better to measure the waveform of the voltage drop between the black line CCB-side high and the voltage drop waveform between the white line CCW-side high and simultaneous. For example, the voltages of waveforms A and B when the same 6A is flowing are measured simultaneously, or the voltages of waveforms AA and BB when the same 7A is flowing are measured simultaneously. By doing so, the voltage drop with respect to the load current at that time can be grasped almost accurately for each of the black and white lines.

(9) Difference voltage detection by simultaneous subtraction and its averaging (1) In order to obtain a more accurate difference voltage value, in the embodiment, the voltage drop waveform on the black line CCB side and the voltage drop waveform on the white line CCW side Are always subtracted during measurement, and the difference, for example, is averaged for one second, and this is used as the differential voltage output (FIG. 27). In this way, even if the measurement current changes due to a change in the 100V power supply voltage or a load during measurement, an almost accurate differential voltage output can be obtained. The explanation will be omitted because it seems understandable if you look at the figure.

9. Finally, in order to better understand the features of the present application, the inventions of the above-mentioned patent documents are compared with the present invention.
(1) Patent Document 1 JP 2001-343416 A Connection Failure Detection Device a. In the present invention, when there is a connection failure due to a contact failure in the breaker internal contact mechanism, or when there is a connection failure between the breaker and the wire connection portion CP, a pure resistor load (linear load), When a current whose waveform is a gentle sine wave is passed through a connection failure location, the voltage waveform or current waveform generated at both ends of the connection failure location does not become the original smooth sine wave, It is presumed that it is formed by applying the characteristic that a spike-like characteristic waveform component appears.
b. As a waveform detection method, a voltage sensor, current sensor or antenna is arranged on the power supply side and load side of the breaker, and these detect spike-like characteristic waveform components. Then, it is determined that there is a connection failure within the detection range, and if it is not detected, it is determined that there is no connection failure. As can be seen from the position of the voltage sensor, this detection range is a narrow range from the earth leakage breaker (earth leakage breaker) of the distribution board to the wiring connected to the earth leakage breaker.
c. Unlike the conventional temperature sensor detection type invention, the present invention is characterized in that a connection failure can be self-diagnosed before overheating caused by a connection failure. However, as can be seen from FIG. 1, FIG. 3, FIG. 4, etc. of the publication, it is necessary to previously incorporate a sensor and a detection device around the breaker side in order to implement the present invention. Such a device is not incorporated in a general household distribution board. For this reason, if it implements, there is no choice but to replace the distribution board in use with the one according to the invention.
d. Differences from the present invention, disadvantageous part-1
As shown in FIG. 28, the connection failure detection range of the present invention is a range surrounded by a broken line (1). On the other hand, in the case of the present invention, the range is the range of the broken line (2). The disadvantages of the above publication are that the detection range is as narrow as (1) and that the range cannot be made large from the signal wiring with the sensor.
Also, as can be seen from the detection principle, in the case of a house with a small operating current, or a house with no load equipment and no operating current, even if there is a connection failure, the connection failure waveform required for judgment cannot be obtained. , Can not detect the defect.
On the other hand, in the present invention, not only the incorporation of the device as in the above-mentioned publication invention is unnecessary, but also a connection failure can be detected for each wall outlet in a wide range from the child breaker B to the wall outlet CW. In addition, connection failure can be detected regardless of the current used and the presence or absence of load equipment.
e. Differences from the present invention, disadvantageous part-2
In the above-mentioned publication invention, a spike-like waveform component included in a sine wave current or a sine wave voltage is used as a criterion for defect determination. For this reason, this cannot be detected in the case of a connection failure in which the contact state does not result in a spike-like waveform output.
In the case of the present invention, regardless of the form of poor connection, and regardless of the current used in the house and the presence or absence of load equipment, as long as there is a resistance increasing component that can generate heat under a constant current, for each wall outlet of the house, Connection failure of the wiring can be detected.

(2) Patent Document 2 JP 2009-145083 A connection failure detection circuit of electric circuit connection part a. The present invention applies a voltage drop that occurs at both ends of a connection portion due to a flowing current when a connection failure occurs in the connection portion between the electric circuit 1a and the electric circuit 1b. In contrast to the detection method, the connection detection can be detected only by connecting the voltage detection line for sensor input to the electric circuit 1a and the electric circuit 1b. A photocoupler (built-in light emitting diode and light receiving transistor) is used as a voltage detection sensor. The light emitting diode in the photocoupler emits light with a small current, but the light emitting diode has a characteristic that current does not start to flow unless a voltage exceeding a certain threshold is applied.
b. Differences from the present invention, disadvantageous part-1
From this operation principle, there are restrictions on the operation of the invention of Patent Document 2. For explanation, the electric circuit 1a, the electric circuit 1b, and the connection portion are shown in FIG. If the threshold voltage is 1. Taking a case where there is a connection failure of R = 0.10Ω at OV as an example, even if there is a connection failure, when the use is continued at a current of 10 A or less, the voltage at both ends of the connection portion becomes the threshold value 1. It does not exceed OV and the sensor circuit does not operate. That is, even if there is a connection failure in the connection portion, the failure cannot be detected unless a current of a certain value or more flows. That is, even if the device according to the invention of Patent Document 2 is attached, it is not always possible to detect a connection failure, and detection is possible only when a certain amount of current flows.
In the case of the present invention, in the connection part CP of the indoor wiring, if the resistance increase value due to the connection failure exceeds a predetermined reference value, it is possible to immediately detect the connection failure regardless of the normal use current of the electric circuit. .
c. Differences from the present invention, disadvantageous part-2
In carrying out the invention of the above-mentioned Patent Document 2, it is necessary to arrange a sensor circuit for each electric circuit connection portion where it is desired to detect a connection failure in advance. The integrated detection circuit aggregates the output signals of the sensor circuits and determines whether there is a connection failure in the integrated detection circuit. Therefore, the sensor circuit mounting position is a close range that can be wired from the integrated detection circuit. When the present invention is applied to an existing electric circuit, it is limited to a connection part such as a distribution board or a terminal board having an opening, in which wiring can be easily confirmed.
The indoor wiring of a house has many connections in concealed places such as behind the ceiling and behind the walls. It is impossible to install the sensor circuit of the present invention in all the connecting parts of the indoor wiring of an existing house in terms of the length of the signal line and the mounting position.
In the case of the present invention, it is not necessary to attach the sensor circuit of the above-mentioned publication invention, and it is possible to detect the presence or absence of a connection failure with the existing indoor wiring.
d. Difference from the present invention, disadvantageous part-3
In the invention of Patent Document 2, a voltage drop due to connection failure of a connection portion is input to a sensor circuit from a voltage detection line connected to both ends of the connection portion, and a photocoupler is operated. Therefore, when it is desired to detect a connection failure in the connection portion of the cable connected to the wall outlet, it is necessary to connect the voltage detection line of the voltage drop to the cable side and the wall outlet side.
However, the voltage detection line cannot be connected to the wall outlet, and in the invention of Patent Document 2, a connection failure on the wall outlet side cannot be detected.
In the case of the present invention, it is possible to detect both a connection failure between the cable and the wall outlet and a connection failure inside the wall outlet device.
(3) Patent Document 3 Japanese Patent Application Laid-Open No. 2008-305564 Regarding Connection Failure Detection Circuit of Circuit Connection Portion The content of the invention of Patent Literature 3 is similar to the content of the invention of Patent Literature 2. Therefore, the difference between the invention of Patent Document 3 and the present invention is substantially the same as the difference between the invention of Patent Document 2 and the present invention. Therefore, a description of the comparison with Patent Document 3 is omitted.

B ... Child breaker Distribution board breaker A ... Used only in Fig. 7 Distribution board breaker B ... Used only in Fig. 7 BL1 ... Fig. 9 Voltage drop measurement unit BL2 ... Fig. 9 Voltage measurement unit BL3 ... Fig. 9 Voltage holding at no load Part BL4 ... FIG. 9 Voltage holding part during load BP ... Reference plug (FIG. 15)
CC ... Alligator clip CCW ... Core wire / white CCB ... Core wire / black CE ... Continuous measurement switch CF ... Contact surface of wall outlet and plug (Fig. 1)
CL ... Leakage detection coil CP ... Connection point CS ... Outlet surface CW ... Wall outlet I to ... Wall outlet in Fig. 8 DB ... Distribution board DT ... Dust and dirt (Fig. 22)
ES: Detection device of the embodiment FC: VVF cable (F cable)
GP ... Gap (Fig. 22)
IS: 3 individual measurement switches
LB ... Leakage breaker LD ... Load resistance LE3 ... 3 horizontal LEDs LE6 ... 6 vertical LEDs MB ... Contract breaker PG ... Plug (general-purpose)
PP ... Plug blade PS ... Polarity changeover switch RS ... Reset switch SE ... Metal probe (Fig. 1)
SW ... Power switch SP ... Measurement plug (Figs. 1 and 15)
TP ... Outlet surface insulation measurement point (Fig. 1)
VS ... Fig. 6 Voltage measurement means

Claims (6)

In indoor wiring wired with two or three core wires, connection means for connecting each core wire to both ends of the target wiring length for connection failure inspection;
Voltage measuring means for measuring a voltage drop amount for each core wire between the target wiring lengths through the connection means;
Differential voltage detection means for comparing the voltage drop amount from the voltage measurement means for each core wire and detecting the difference amount ; and
Display means for judging the quality from the detected difference and displaying the result ;
An indoor wiring connection failure detection device characterized by comprising:   The indoor wiring connection failure detection device according to claim 1, further comprising load means connected to the connection means connected to one end side of the target wiring length.   3. The indoor wiring connection failure detection device according to claim 1, wherein either or both of the two connection means are plugs connected to an outlet provided indoors. Using the indoor wiring connection failure detection device according to claim 1, 2, or 3, the voltage drop amount for each core wire is measured by the connecting means connected to both ends of the target wiring length, and the measurement is performed. A connection failure determination method characterized by determining the presence of a connection failure in an electrical circuit of a core wire having a larger voltage drop amount when the difference in voltage drop amount is equal to or greater than a predetermined value. Characterized in that the target wiring is at the currentless state, drawing a load current by a load means connected to one of said connection means, for measuring the voltage drop difference by detecting a voltage drop amount of each core connection failure determination method according to claim 4, wherein the said.   The object wiring length to be inspected is specified between different outlets to which wirings of different paths branched from the distribution board are connected, and connecting means configured as plugs are fitted to the respective outlets. 4. The connection failure determination method according to 4.

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