JP2010259226A - Electric wire passing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric wire passing method which passes an electric wire to a hole which communicates with the inside and the outside of a device without causing the electric wire to contact with connections in a charging state. <P>SOLUTION: The electric wire passing method draws out and pushes in the electric wire by attaching an electric wire protection pipe 1 to the electric wire 30 while covering the connections in the charging state from outside. The electric wire protection pipe 1 is simple in constitution and low in price. According to such an electric wire passing method, there is no risk that the connections in the charging state contacts with the electric wire in the hole for the electric wire introduction of a low-voltage current transformer, and thus the electric wire 30 in a live state can be drawn out and pushed in through the hole. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wire threading method that allows a charged connection portion to pass through a hole communicating with the inside and outside of the apparatus in a non-contact manner so that a live wire can be handled.

  Do electrical meters that measure electricity, such as measuring electricity used at customer facilities, comply with the technical standards stipulated by the Measurement Act by public institutions (Nippon Electric Meters Laboratory, hereinafter referred to as NIPPON TEST)? Tests have been conducted to determine whether or not. The measuring accuracy of the electric meter is publicly proved by the test, and accurate weighing is performed.

There are various types of such electric meters according to the scale of power demand of consumers, and they are roughly classified into single electric meters and electric meters with transformers.
A single electric meter is an electric meter that measures the amount of electricity used by a mechanical type or an electronic type alone, and only a watt hour meter is provided for each type of equipment. By class, there are only ordinary watt-hour meters, and by phase line, there are single-phase two-wire, single-phase three-wire, three-phase three-wire, and three-phase four-wire.

The electric meter with a transformer is an electric meter that measures using a mechanical or electronic combination electric meter and a current transformer (CT), and only the watt hour meter is classified by device type. By class, there are only ordinary watt-hour meters, and by phase line, there are single-phase two-wire, single-phase three-wire, three-phase three-wire, and three-phase four-wire.
In this specification, an electric meter with a transformer and a single electric meter are collectively referred to simply as an electric meter.

An instrumental current transformer (CT) is a device that connects a primary winding in series to a large current circuit and transforms a secondary current proportional to the primary and secondary windings. The rated secondary current of the transformer is generally 5 [A] regardless of the primary current. In other words, the current flowing between a customer with a large contracted capacity and a customer with a small contracted capacity is significantly different, but by using a current transformer (CT) with a corresponding winding ratio, the secondary current is always reduced. I try to keep it within the rated range.
The electric energy of the consumer is calculated by multiplying the electric energy measured by the instruments by a constant corresponding to the winding ratio of the instrument current transformer (CT).

  Such electric meters have received the above-mentioned type approval / certification by the NIPPON DENKO when shipped from the factory, and can be installed and used immediately in customer facilities. This certification has a valid period (hereinafter referred to as the valid examination period), and existing products that are installed and measured at customer facilities must be replaced with the certified electric meter before the valid period expires. is there.

  Therefore, the electric power company that manages the electric meter currently performs revocation management to manage the verification validity period of the existing electric meter, and before the expiration of the verification validity period (hereinafter referred to as expiration), In place of the instrument, work will be done to install other certified electrical instruments.

  A specific example of such construction will be described with reference to the drawings. As shown in the explanatory diagram for explaining the revocation replacement example in FIG. 7, an electric wire (lead wire) 30 is stretched between the utility pole 10 and the building 20, and a meter with a low-voltage current transformer is connected to the electric wire (lead wire) 30. 40 is connected and finally drawn into the inside of the building 20 through the switch 50.

  This meter 40 with a low-voltage current transformer is a specific example of the electric meter described above, and includes a watt-hour meter (WHM) 41 and a low-voltage current transformer 42. The low-pressure current transformer 42 is a box made up of a box part 421 and a lid part 422 as shown in a specific example of the low-voltage current transformer of FIG. , 425, 426, 427, 428, and the electric wires 30 are inserted into the holes 423, 424, 425, 426, 427, 428, respectively. And it fixes to the wall surface of the building 20 with the attachment leg 429. FIG. FIG. 8 illustrates a low-pressure current transformer 42 such as a single-phase three-wire system or a three-phase three-wire system. The hole part of a location will be formed.

  Further, the other low-voltage current transformer 42 'is a box made up of a box part 421' and a cover part 422 'as shown in a specific example of the low-voltage current transformer of FIG. Are provided with holes 423 ′, 424 ′, 425 ′, 426 ′, 427 ′, and 428 ′, and the electric wire 30 is inserted into these holes 423 ′, 424 ′, 425 ′, 426 ′, 427 ′, and 428 ′. The And it fixes to the wall surface of the building 20 with the attachment leg 429 '. FIG. 9 shows an example of a single-phase three-wire type, three-phase three-wire type low-voltage current transformer 42 '. The hole part of a location will be formed.

  Then, as shown in FIG. 7, the conventional method of the expiring replacement work is to cut one of the cutting / connection points 31 and 32 of the electric wire (lead-in wire) 30 so that the customer side is in a power failure state, and the watt hour meter (WHM) 41, low-voltage current transformer 42 is removed and then replaced with a new certified watt-hour meter (WHM) 41, low-voltage current transformer 42, and disconnection / connection point 31 (or 32) is connected to expire. It is to end the end.

By the way, in the conventional method of expiring replacement work, the cutting and connection of the electric wire (lead-in wire) 30 is performed at a high place, which is dangerous and requires work time. If possible, avoid such cutting and connection. There was a request to do.
This was not limited to expiring replacement work, but was also the same for failure replacement work of existing electric meters (hereinafter collectively referred to as electric meter replacement work). As described above, there is a demand to replace the electric meter without disconnecting / connecting the electric wire (lead wire) 30. In this case, the electric wire (lead-in wire) 30 is handled in a live line state, and in particular, it is necessary to take insulation measures for the connection part in the charged state at the tip of the electric wire (lead-in wire) 30.

As specific examples of the related art relating to such insulation measures for connecting portions, for example, Patent Document 1 (Japanese Patent Laid-Open No. 08-79934, title of the invention “insulation cap for electric wire terminal”) and Patent Document 2 (Japanese Patent Laid-Open No. 2007-2007). -141706 gazette, the name of the invention "temporary fixing structure of sleeve member and insertion member and hot wire connection method") and the like are known.
In the prior arts described in Patent Documents 1 and 2, in particular, the insulation measures are taken by putting a cap on the charged connection portion at the tip of the electric wire.

Japanese Patent Laid-Open No. 08-79934 (FIGS. 1 and 3) JP 2007-141706 A (FIG. 1)

However, there has been a situation that the cap described in Patent Documents 1 and 2 cannot be simply applied in the replacement work of the electric meter.
In the low-pressure current transformer 42 ′ described above with reference to FIG. 9, holes 423 ′, 424 ′, and 425 ′ are formed by abutting the semicircular grooves on both sides of the box portion 421 ′ and the lid portion 422 ′. , 426 ′, 427 ′, and 428 ′, and when the cover 422 ′ is opened, the holes 423 ′, 424 ′, 425 ′, 426 ′, 427 ′, and 428 ′ are opened, and the electric wire 30 is connected. It can be removed. For this reason, even when the electric wire 30 in which the connecting portion at the tip is in a charged state is handled, the electric wire 30 is relatively easy to remove.

  On the other hand, in the low-pressure current transformer 42 described above with reference to FIG. 8, the holes 423, 424, 425, 426, 427, and 428 are through holes provided in the side surface of the box 421, so There was a problem in pulling out the wire 30 as it was. Such low-voltage current transformers 42 have already been installed in many buildings, and are often subject to replacement in the replacement work of electric meters. It is not easy to pull out a certain electric wire 30 and it is easy to induce an accident such as a short circuit.

  Therefore, it is conceivable to pull out the cap described in Patent Documents 1 and 2 after covering the charged connection portion, but the connection portion is exposed to the outside even when the connection portion of the electric wire 30 is removed from the terminal portion. It was dangerous. There was a request to allow safer removal considering the removal of the terminal part.

  Then, this invention is made | formed in view of the above-mentioned problem, The objective is to provide the electric wire threading method which allows an electric wire to pass through, without making the connection part of a charged state contact the hole part connected inside and outside of an apparatus. It is in.

The wire threading method according to claim 1 of the present invention is:
An electric wire is inserted through the hole, and the wire connecting method for pulling out the charged connection portion from the hole portion of the device with respect to the device in which the connecting portion of the electric wire is detachably attached to the terminal portion,
A wire protection tube mounting step for mounting the wire protection tube so that the wire protection tube can be moved to the wire inserted in the hole of the device;
A wire protection tube pushing-in process of pushing the wire protection tube into the hole of the device until it abuts the terminal part;
A connecting portion removing step of removing the connecting portion of the electric wire from the terminal portion;
An electric wire drawing process for alternately pulling out the electric wire and pushing in the electric wire protective tube and pulling out the electric wire until the connecting portion is hidden in the electric wire protective tube;
A wire protection tube fixing process for fixing the wire protection tube to the wire;
A wire drawing process for drawing the wire together with the wire protective tube from the hole;
It is characterized by having.

Moreover, the electric wire threading method according to claim 2 of the present invention is:
An electric wire is inserted through the hole, and the electric wire passing method for pushing the electric connection portion into the hole portion of the device, with respect to the device in which the electric wire connection portion is detachable from the terminal portion,
A wire protection tube mounting step of attaching a wire protection tube to the wire so as to cover the connection part;
A wire protection tube / wire push-in process in which the wire protection tube and the wire are pushed into the hole of the device until it contacts the terminal part;
A connecting portion attaching step for attaching the connecting portion of the electric wire to the terminal portion;
A wire protection tube removal process for removing the wire protection tube;
It is characterized by having.

Moreover, the wire threading method according to claim 3 of the present invention is:
In the wire threading method according to claim 1 or claim 2,
The device is a current transformer for measuring the amount of electric power in the AC circuit.

  ADVANTAGE OF THE INVENTION According to this invention, the electric wire threading method which lets an electric wire pass through without making the connection part of a charged state contact the hole part connected inside and outside of an apparatus can be provided.

It is an electric wire threading method of the form for implementing this invention, Comprising: It is explanatory drawing of attachment of the electric wire protection tube to an electric wire. It is an electric wire threading method of the form for implementing this invention, Comprising: It is explanatory drawing of an electric wire extraction method. It is an electric wire threading method of the form for implementing this invention, Comprising: It is explanatory drawing of an electric wire extraction method. It is an electric wire threading method of the form for implementing this invention, Comprising: It is explanatory drawing of an electric wire extraction method. It is an electric wire threading method of the form for implementing this invention, Comprising: It is explanatory drawing of an electric wire pushing method. It is an electric wire threading method of the form for implementing this invention, Comprising: It is explanatory drawing of an electric wire pushing method. It is explanatory drawing explaining the example of revocation work. It is a figure which shows the specific example of a low voltage current transformer. It is a figure which shows the specific example of a low voltage current transformer.

  Then, the wire threading method of the form for implementing this invention is demonstrated below, referring FIGS. First, an electric wire threading method for pulling out an electric wire by pulling out a connected portion in a charged state from a hole of the apparatus will be described with reference to the drawings. In this method, for concrete explanation, an apparatus for drawing out the electric wire is an existing low-voltage current transformer, and this low-voltage current transformer is the old-type low-voltage current transformer 42 shown in FIG. Will be described.

  First, the worker checks the electric power and confirms that the electric wire 30 is in a live line state and the connecting portion is being charged. Specifically, in this step, the arc-proof surface and low-pressure gloves are worn, the lid portion 422 of the current transformer 42 in FIG. 8 is removed, and the box of the low-voltage current transformer 42 shown in FIG. The terminal 430 (connection part 33) in the part 421 detects the current and confirms that charging is in progress.

  Subsequently, the worker checks the current transformer primary side wiring connection state and the current transformer secondary side wiring connection state. In this step, specifically, the connection state of the primary side wiring and the secondary side wiring of the low-voltage current transformer 42 is confirmed, and the connection status is entered in a check form. When the color of the electric wire 30 is unknown, such as a CV cable wound with an adhesive polyethylene tape, the color is displayed by tape winding.

  Subsequently, the worker attaches a ground terminal protective cover to the primary side ground terminal in order to protect the primary side ground terminal of the low-voltage current transformer 42. Specifically, in this step, a grounding terminal protective cover is attached so that the charging part is not exposed to the primary ground terminal of the low-voltage current transformer 42.

  Subsequently, the worker attaches the wire protection tube 1 to the primary side wire and pulls out the primary side wire to pull out the primary side wire of the low-voltage current transformer 42. This process corresponds to the wire threading method according to the present invention.

  An operator attaches the electric wire protection tube 1 to the electric wire 30 that is inserted through the hole of the low-voltage current transformer 42 so that the electric wire protection tube 1 can be moved (electric wire protection tube attachment step). Initially, the wire protection tube 1 is inserted into the wire 30 which is the primary side wire.

  The electric wire 30 and the electric wire protection tube 1 are as shown in FIGS. 1A and 1B, and the electric wire protection tube 1 is attached to the electric wire 30. The wire protection tube 1 is formed so as to be deformable by, for example, hard rubber as an insulator, and a single plate is formed into a cylindrical body in a state as shown in FIG. Usually, it is stable in the shape as the wound body, and the cut portion 2 is formed. The cutting portion 2 of the wire protection tube 1 is expanded to form an introduction portion 3 as shown in FIG. 1 (c), and the wire protection tube 1 is placed inside through the introduction portion 3. Return to the original winding body. Thereby, as shown in FIG.1 (d), the electric wire protection tube 1 covers the circumference | surroundings of the electric wire 30, and is attached so that a movement is possible.

  Subsequently, the worker moves the wire protection tube 1 along the wire 30 and pushes the wire protection tube 1 into the hole 423 as shown in FIG. 2A, as shown in FIG. 2B. The wire protective tube 1 is pushed into the hole 423 until it contacts the terminal portion 430 (wire protective tube push-in step). In addition, although the hole part 423 was illustrated in figure in the several hole part, it is the same also in the other hole parts 425, 426, and 428, and only the hole part 423 will be described below, and the redundant description is omitted for others. To do. In addition, since the electric wire 30 inserted into the holes 424 and 427 is a ground wire, it is not necessary to use the electric wire protection tube 1, but a method of using the electric wire protection tube 1 may be used for completeness.

  Then, an operator removes the connection part 33 of the electric wire 30 from the terminal part 430 (connection part removal process). For example, as shown in FIG. 3A, the hexagon bolts at the four locations of the terminal portion 430 are loosened.

  Subsequently, the worker alternately performs the wire drawing as shown in FIG. 3A and the wire protection tube pushing-in as shown in FIG. 3B, and the wire protection tube attached while gradually pulling out the wire 30. 1 is inserted, and the wire 30 is pulled out until the connecting portion 33 is hidden in the wire protection tube 1 as shown in FIG. 4A (wire drawing step). The electric wire pull-out and the electric wire protection tube push-in are performed over many short distances, thereby avoiding as much as possible the state in which the connecting portion 33 that is the charging portion is exposed to the outside.

  Subsequently, as shown in FIG. 4A, the worker provides the fixing portion 4 to fix the wire protection tube 1 to the wire 30 (wire protection tube fixing step). When the end of the connection portion 33 of the electric wire 30 comes to the inside of the electric wire protective tube 1 by about 1 cm, the end of the electric wire protective tube 1 is taped to form the fixing portion 4, and the electric wire protective tube 1 is fixed to the electric wire 30. . The connecting part 33 which is a charging part is not exposed to the outside world.

  Subsequently, as shown in FIG. 4B, the worker pulls out the electric wire 30 together with the electric wire protection tube 1 from the hole (electric wire drawing step). Before pulling out, the worker first confirms again that the connecting portion 33 is not exposed from the tip of the wire protection tube 1, and then the wire 30 and the wire while taking care not to bring the wire 30 into contact with other objects. Pull out the protective tube 1 together. In this way, the wire threading method for wire drawing is performed.

  Subsequently, the worker removes the electric wire protection tube 1 from the drawn electric wire 30, protects the connection portion 33, which is a charging portion, using an electric wire end cap or tape, and removes it from the voltage line and finally removes the ground wire.

  Subsequently, the worker will remove the existing instrument and current transformer. Specifically, the load side (secondary side) electric wire 30 of the low voltage current transformer 42 is removed, the low voltage current transformer 42 is removed, and the watt hour meter (WHM) 41 is removed. At this time, it is necessary to check the surrounding situation and handle it carefully so as not to drop it when the watt-hour meter (WHM) 41 or the low-voltage current transformer 42 is removed.

  Subsequently, the worker installs a new current transformer and a new design device. For example, a new low-pressure current transformer 42 ′ as shown in FIG. 9 may be used, but the explanation will be made assuming that it is the old-type low-voltage current transformer 42 shown in FIG. 8 for convenience of explanation. The low-pressure current transformer 42 is installed in the same direction as before removal. When installing the watt-hour meter (WHM) 41 or the low-voltage current transformer 42, handle it carefully so as not to drop it.

In this case, a wire threading method for wire insertion for inserting the charged connection portion into the hole of the device is performed.
The worker attaches the wire protection tube 1 to the wire 30 so as to cover the connection portion 33 of the wire 30 as shown in FIG. 5A (wire protection tube attachment step). The worker again attaches the electric wire protection tube 1 to the electric wire 30 and further removes the electric wire terminal cap or the tape attached for protection to the connecting portion 33 which is the charging portion by the electric wire passing method related to the previous electric wire drawing.

  Subsequently, as shown in FIG. 5B, the worker pushes the wire protection tube 1 and the wire 30 into the hole 423 of the box portion 241 until the contact with the terminal portion 430, and pushes it to the stop position (wire Protective tube / wire push-in process).

  Subsequently, as shown in FIG. 6A, the worker pushes the connecting portion of the electric wire into the terminal portion 430 and connects it to the terminal portion 430 (connecting portion attaching step). For example, as shown in FIG. 6A, the hexagonal bolts at the four locations of the terminal portion 430 are tightened so that the terminal portion 430 is sandwiched.

Subsequently, as shown in FIG. 6B, the worker removes the wire protection tube 1 from the wire 30 (wire protection tube removal step). This is achieved by pulling out the wire protection tube 1 along the wire 30.
In the same way, the replacement work of the electric meter is performed in the same manner.

The electric wire threading method related to electric wire drawing and electric wire pushing has been described above.
According to such a wire threading method, it is possible to perform replacement work even if the wire is live, particularly in replacement work for instruments with low-voltage current transformers. Therefore, convenience for electric power companies is improved.
Furthermore, this method has the advantages of shortening the power outage time, eliminating the need for disconnection / connection (power supply stop / restart work) by power company workers, and improving safety due to the elimination of work at high places.
In addition, the wire passing method has been explained with the instrument replacement work in mind, but it is not intended to be limited to replacement work, and the wire passing method of the present invention can be widely applied in general construction that allows live wires to pass through the hole. It is.

  The wire threading method of the present invention can be applied particularly when inserting and removing a live wire in a hole of the apparatus.

1: Electric wire protection tube 2: Cutting part 3: Introduction part 4: Fixed part 10: Utility pole 20: Building 30: Lead-in wire 31, 32: Cutting / connection point 33: Connection part 40: Meter 41 with a low-voltage current transformer: Electric energy Total (WHM)
42: Low pressure current transformer 421: Box portion 422: Cover portion 423: Hole portion 424: Hole portion 425: Hole portion 426: Hole portion 427: Hole portion 428: Hole portion 429: Mounting leg 430: Terminal portion 42 ': Low pressure Current transformer 421 ′: Box portion 422 ′: Cover portion 423 ′: Hole portion 424 ′: Hole portion 425 ′: Hole portion 426 ′: Hole portion 427 ′: Hole portion 428 ′: Hole portion 429 ′: Mounting leg 50: Switch

Claims (3)

An electric wire is inserted through the hole, and the wire connecting method for pulling out the charged connection portion from the hole portion of the device with respect to the device in which the connecting portion of the electric wire is detachably attached to the terminal portion,
A wire protection tube mounting step for mounting the wire protection tube so that the wire protection tube can be moved to the wire inserted in the hole of the device;
A wire protection tube pushing-in process of pushing the wire protection tube into the hole of the device until it abuts the terminal part;
A connecting portion removing step of removing the connecting portion of the electric wire from the terminal portion;
An electric wire drawing process for alternately pulling out the electric wire and pushing in the electric wire protective tube and pulling out the electric wire until the connecting portion is hidden in the electric wire protective tube;
A wire protection tube fixing process for fixing the wire protection tube to the wire;
A wire drawing process for drawing the wire together with the wire protective tube from the hole;
An electric wire threading method characterized by comprising: An electric wire is inserted through the hole, and the electric wire passing method for pushing the electric connection portion into the hole portion of the device, with respect to the device in which the electric wire connection portion is detachable from the terminal portion,
A wire protection tube mounting step of attaching a wire protection tube to the wire so as to cover the connection part;
A wire protection tube / wire push-in process in which the wire protection tube and the wire are pushed into the hole of the device until it contacts the terminal part;
A connecting portion attaching step for attaching the connecting portion of the electric wire to the terminal portion;
A wire protection tube removal process for removing the wire protection tube;
An electric wire threading method characterized by comprising: In the wire threading method according to claim 1 or claim 2,
The above-mentioned device is a current transformer for measuring the amount of electric power of an AC circuit.

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