JPH0530631A - Joint of high voltage flame-retardant cable - Google Patents

Abstract

PURPOSE:To make it possible to form a flame-retardant coating readily at the outside of joint or branch of high voltage flame-retardant cable and to make it possible to protect inner conductors or other insulating members by means of the flame-retardant coating. CONSTITUTION:At a joint 10 of high voltage flame-retardant cables 1, 1a, conductors 2, 2a of the cables are jointed through a conductor joint tube 11 and the joint is subjected, over a predetermined range thereof, to insulation treatment similar to that for general high voltage cable. A flame-retardant filler 25 is then wound around the joint and a protective case member 20 is applied thereon followed by flame-retardant insulation treatment. The protective case member 20 may be a set of semicylindrical aluminum members and the flame-retardant filler 25 may be a thermally curable material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a connection part of a high-voltage fireproof cable, and more particularly, to the surface of the connection part of the high-voltage cable.
The present invention relates to a connection portion of a high-voltage fireproof cable protected by a protective case member and a fireproof filler.

[0002]

Background of the Invention and Prior Art In recent years, there is a tendency for the demand for electric power in office buildings to increase, and in order to meet the demand for electric power, the main distribution system in the building is constructed using high-voltage fireproof cables. Equipment that supplies power to each demand destination is often used through substation equipment installed on each floor or the like. However, the cable used for the power supply system in the building should have fire resistance performance as specified in Fire Service Agency Notification No. 7 (October 16, 1978), especially in the case of high voltage. Is required to do. The fire resistance required for the high-voltage fireproof cable is required to be such that a power supply can be continued without a short circuit or the like in a state of being left inside a heating furnace heated to 840 ° C. for 30 minutes. ing.

Therefore, in a general high-voltage fireproof cable, a means such as winding mica tape around the conductor is used,
Even if the insulator or sheath that covers the surroundings burns, the mica tape that covers the conductors can maintain the insulating state, and even if a fire accident occurs, use a means to continue power supply. There is. When connecting the high-voltage fireproof cable as described above, for example, as shown in FIG.
The connection means as shown in Fig. 4 is used to maintain the insulation of the cable connection even when the high voltage cable connection is exposed to high temperatures.

As shown in the high-voltage cable connecting portion 10a of FIG. 14, the high-voltage fireproof cables 1 and 1a have their conductors 2 covered with mica tape 5, and their periphery covered with an insulator 3 and a sheath 4. It is configured to cover. When connecting the high-voltage refractory cables 1 and 1a, the sheath 4 and the insulator 3 are stripped to remove the conductors 2 and 2.
Is exposed, and the tip of the conductor is inserted into the conductor connecting pipe 11, and compressed and fixed to connect. A mica tape is wound in multiple layers to form a refractory layer 12 around the connecting portion using the conductor connecting tube 11, and a self-bonding tape is provided over the refractory layer and the periphery of the insulator of the high-voltage refractory cable. The reinforcing insulator 13 wound in multiple layers is formed. Further, the reinforcing insulator 1
On the surface of 3, a conductive tape 14, a flat braided copper wire 15 to be connected to the shielding copper tape of the cable, and a copper bind wire 16 are provided, and the periphery thereof is covered with a fireproof protective layer 17, and a waterproof tape. And the anticorrosion layer 18 according to the above.

By constructing the high-voltage cable connecting portion 10a as described above, even if the high-voltage cable connecting portion is exposed to a high temperature due to a fire or the like and the coating member on the surface burns, the fire-resistant protective layer 17 is formed. The layer can protect the members inside thereof. Further, even if the lower layer member covered with the fireproof protective layer 17 burns, the fireproof layer 12 covering the conductor and the periphery of the conductor connecting pipe 11 maintains the insulating action, so that the high-voltage fireproof cable is provided. There will be no problems such as short circuit.

[0006]

In the conventional high-voltage cable connecting portion 10a shown in FIG. 14, the fireproof layer 12 and the fireproof protective layer 17 are made of a tape-like material usually called mica tape, and the mica tape is It is formed by wrapping it in multiple layers with a 1/2 wrap. However, since the mica tape is formed by sticking a thin piece of mica (mica) to a glass cloth, it is inflexible and the winding work is troublesome, so it takes time to connect the high pressure fire resistant cable. There is a problem in that the cost is high and the connection cost of the high-voltage fireproof cable is very high. Also, in order to increase the power feeding capacity of the cable, it is necessary to configure the high-voltage fireproof cable with a thick one, and when applying the connecting means as described above to a thick high-voltage fireproof cable, stable insulation performance is required. It has become difficult to maintain.

However, in the conventional high-voltage fireproof cable, since there is no connection method other than using the high-voltage cable connection portion as shown in FIG. 14, the work of winding the mica tape is carefully performed to ensure sufficient insulation performance. A fire resistant layer or a fire resistant protective layer is formed so as to be able to secure it. Therefore, in order to minimize the formation of the high-voltage cable connecting portion as described above,
In many cases, the power feeding method as shown in is used. That is, when the transformer P is arranged on each floor in the building B and the electric power is supplied from the electric room E, the transformers P, P ... In order to minimize the number of parts that connect high-voltage fireproof cables, Then, in FIG.
In the case of constructing a power supply system such as shown in Fig. 1, since the connecting member attached to the transformer on each floor is used, there is no need to use a branch connection part, and the feature that the distribution system can be easily constructed. Can be demonstrated.

However, when the power feeding method as shown in FIG. 15 is adopted, it is necessary to connect a short high-voltage fireproof cable to each transformer on each floor, which is a troublesome work. is there. Further, when changing the power supply capacity in a building, it is troublesome to lay and replace short high-voltage fireproof cables, which requires a lot of man-hours. On the other hand, for example, as shown in Japanese Patent Application Laid-Open No. 2-21583, when a connector is arranged at a position corresponding to each floor for a large capacity low voltage main line arranged in an electric duct of a building. Is configured so that it is possible to easily change the capacity of the trunk cable and change the power receiving capacity. However, when using a high-voltage fireproof cable, for example, when applying a means for branching from a high-voltage trunk line through a connector to a transformer on each floor, the connector portion is covered with a fireproof protective layer. However, there is a problem in that it is completely impossible to remove the connector when it is covered with a fireproof protective layer.

[0009]

It is an object of the present invention to simplify a fireproof connection structure of a high-voltage fireproof cable in a power supply system using a high-voltage fireproof cable, and to branch by using a connector so that the mechanism of the connecting portion can be simplified. At the same time, it is an object of the present invention to provide a connection portion of a high-voltage fireproof cable that can improve the fire resistance of the connection portion.

[0010]

According to the present invention, the cable conductors can be connected to each other on the intermediate conductor connecting portion where the cable conductors can be connected by the conductor connecting pipe or the plug-lessep method, or the cable conductor end can be connected to the conductor fitting for suspending the cable conductor. The present invention relates to a connection portion of a high-voltage fireproof cable, which is provided with at least a reinforcing insulator and an outer semiconductive layer on the periphery of the termination conductor connection portion. In the present invention, a protective case member is arranged so as to cover the surface of the high-voltage fire-resistant cable connection portion, and a fire-resistant filler having a predetermined thickness is filled between the high-pressure fire-resistant cable connection portion and the protective case member. Is used. In the connection part of the high-voltage fireproof cable of the present invention, the protective case member is made of a material having a property of being melted by high heat, and is cured at a high temperature between the protective case member and the high-voltage cable connection part. It is possible to fill the putty member having the property to do so. Further, in the present invention, the protective case member is made of a material having a property of not melting at high temperature, and a putty member having foamability at high temperature is filled between the protective case member and the high-voltage cable connecting portion. You can also do it.

The protective case member constituting the above may be formed, for example, by vertically dividing a cylinder into two parts, and the inside of the two-part cylindrical member may be filled with a refractory filling to a predetermined thickness. The work of assembling the high-voltage cable connecting portion can be easily performed by using the one arranged in step 1. Also,
For single-core cables, as the protective case member,
It is possible to use glass, rubber, plastic, aluminum, and other materials that melt at high temperatures, or materials that do not melt even at high temperatures, such as copper, copper alloys, stainless steel, ceramics (ceramics), calcium silicate, and magnesium. . In addition, a protective case member made of iron can be used for the multi-core cable.

Further, in the high-voltage cable connecting portion of the present invention, as the putty member, one generally used for fire prevention of cable lines can be used, and for example, one having a property of being hardened by heat or It is also possible to use a refractory filling having a property of foaming by applying heat. Since the refractory filling has the property of expanding by heat, it is heated to a high temperature even if there is a slight gap between the outer coating layer of the high-voltage refractory cable and the inside of the protective case member. In that case, the gap can be filled, and the protective action of the protective case member and the refractory filling can be exerted. In addition to the basic refractory coating structure as described above, in the present invention,
In addition to the fireproof structure of the connection portion of the high-voltage fireproof cable, the fireproofness can be ensured even for the high-pressure branch portion using the branch socket. In addition, the fire-resistant structure of the present invention can be used as a fire-proof coating means in a portion where a cable is suspended in an electric shaft of a building or the like, and can also be used for a high-voltage fire-resistant cable at a desired location. It can be applied as a coating support means.

By configuring as described above, the high-voltage fireproof cable connecting portion of the present invention is used not only for connecting two cables in a straight line, but also for forming a connector, for treating a cable end, etc. When performing, it is possible to ensure the fire resistance of the connection part. Further, since the fireproof structure of the present invention is subjected to almost the same connection processing as in the case of a normal high-voltage cable, it is only constructed by combining a fireproof filler and a protective case member on the surface of the connection portion. The fireproofing can be easily performed, and the fireproofing performance at the high-voltage fireproof cable connecting portion can be easily ensured.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The connection part of a high-voltage fireproof cable according to the present invention will be described with reference to the illustrated example. The example shown in FIG.
1 shows a structure of a portion to which a high-voltage fireproof cable is connected. As the high-pressure fireproof cable 1, the mica tapes 5 and 5a are formed on the surfaces of the conductors 2 and 2a in the same manner as a general fireproof cable.
Is used. In the high-voltage fire-resistant cables 1 and 1a shown in FIG. 1, an external semi-conductive layer made of a semi-conductive tape, for example, carbon-containing butyl rubberized polyester non-woven tape between the insulator layers 3 and 3a and the sheaths 4 and 4a. 6, 6a and a metal shield layer 7 made of copper tape
What is formed by coating a and is used. In the high-voltage cable connecting portion 10 shown in FIG. 1, the connecting end portions of the two high-voltage fireproof cables 1 and 1a to be connected have the exposed portions of the conductor 2 as in the case shown in FIG. , Is inserted into the hole of the conductor connecting pipe 11 and fixed by compression.

Further, the surface coating layer 4 on the surface of the cable is peeled off in a predetermined range, and the fireproof tapes 5 of the cables on both sides are removed.
A semiconductive layer 8 is formed around the portion 5a and the sleeve 11, and then a self-bonding tape is wound around the exposed portion of the insulating layer 3 and the surface of the conductor connecting pipe 11. A reinforced insulator 13 is provided. The semiconductive layer 8 is provided in order to relieve stress caused by scratches or the like that occur when the conductor connecting tube 11 is attached. A semiconductive rubber tape is wound around the semiconductive layer 8 or made of a semiconductive material. A shrinkable tube can be attached. Further, an outer semiconductive layer 14 formed by winding a semiconductive tape, for example, a carbon-containing butyl rubberized polyester non-woven tape on the surface thereof is applied over the shielding layers 7 and 7a of the cables on both sides, and the surface thereof is flat knitted. A connection portion shielding layer 9 including a copper wire and a bind wire is formed, and the surface thereof is covered with an anticorrosion layer 18 formed by winding a waterproof tape. That is, in the high-voltage cable connection portion 10 of the present invention, the processing of the connection portion of the high-voltage fireproof cable is performed in the same manner as the processing for the connection portion of the conventional cable in general, but the connection portion is wrapped with mica tape or the like to prevent fire. It is not necessary to form a protective layer.

As described above, after connecting the conductor of the high-voltage fireproof cable, in the present invention, the surface of the connecting portion is covered with the fireproof filler 25, and the protective case member 20 is attached and fixed to the outside thereof. . Examples of the refractory filling 25 include (DF putty N, manufactured by Mitsubishi Cable Industries, Ltd.
DF putty A ... All can use the brand name). The putty used as the refractory filling is, for example,
DF putty N is made of a material that solidifies when it comes into contact with a flame and then forms a hard carbonized layer, and when heated to a high temperature, its shape does not collapse,
It is designed to hold and protect the internal cables.

When the DF putty A is in contact with a flame, it is carbonized and foamed at about 300 ° C., the expansion pressure thereof closes the voids, and the DF putty A can exhibit hardening such as heat insulation. Since all of these DF putties are formed into a sheet shape, a rod shape, or the like, in the present invention, the sheet shape is wound around the high-voltage cable connection portion to form a fireproof filling material. can do. Further, the protective case member 2 is provided on the surface on which the refractory filling is applied.
When constructing No. 0, even if there is a slight gap between the high-voltage cable connecting portion and the waterproof tape 18, the refractory filling has plasticity, and due to the pressing force when mounting the protective case member. The refractory filling can be deformed to fill the gap.

In the high-voltage cable connecting portion 10 of the present invention constructed as described above, the protective case member arranged on the outer side thereof has a shape in which a cylinder is divided into two, as shown in FIGS. Can be used.
The protective case member shown in FIG. 2 is provided by dividing a cylinder into two and projecting a flange 21 at the mating portion thereof.
The flange portion can be fixed with a bolt or the like. Further, in the protective case member 20a shown in FIG.
It is possible to use a means in which the end portions of the two semi-cylindrical members are overlapped with each other, and the tightening band 22 is arranged on the outer side of the end portions and fixed. Furthermore, in the example of the protective case member 20b shown in FIG. 4, it is possible to use a means for tightening and fixing with the tightening band 22 in a state where the ends of the semi-cylindrical are joined.

In the means for protecting the surface of the high-voltage cable connecting portion using the protective case member as described above, the present invention has a property that the protective case member melts at a high temperature and a property that it does not melt at a high temperature. The thing different from the thing in the property of the refractory filling with which the inside is filled can be used. For example, when glass, rubber, plastic, aluminum, or any other material that melts at high temperature is used as the protective case member having the property of melting at high temperature, the refractory filler to be filled inside the protective case member may be, for example, A material having self-hardness when exposed to a high temperature such as DF putty N can be used. Then, even if the protective case member melts at a high temperature of 840 ° C., for example, the refractory filling is hardened to form an outer protective layer of the high-voltage cable connecting portion, and the inner protective member is burned. Can be prevented.

On the other hand, as the protective case member, for example, a material such as copper, copper alloy, stainless steel, ceramic (ceramic), calcium silicate, magnesium silicate, etc. which does not melt at high temperature is used as the protective member for the surface of the single-core cable. In the case of using a protective case member made of iron for a multi-core cable, the refractory filling material filled in the protective case member is exposed to high temperature to be self-hardening. It is not necessary to limit the material to be used. That is,
In that case, since the protective case member does not burn or melt at high temperature, only the heat insulating property is required for the refractory filling material. Therefore, when the protective case member has a property of not melting, by applying heat as a refractory filling like the DF putty A,
A material having the property of foaming and expanding can be used. In addition, since the refractory filling as described above has the property of expanding by heat, even if there is a slight gap between the outer coating layer of the high-voltage refractory cable and the inside of the protective case member, the fire-resistant filling can be used. When an object is heated to a high temperature, it expands to fill the gap, and the protective action of the protective case member and the refractory filler can be exhibited well.

The fireproof structure at the connecting portion of the high-voltage fireproof cable of the present invention is not limited to the connecting portion using the conductor connecting pipe as shown in FIG. 1, but a plug / reset type (so-called tulip contact type, plug type). The fire resistant structure of the present invention can also be applied to a connection portion configured by an in-type or the like). Further, the fire resistant structure of the connection portion of the present invention can be applied to a single-core or multi-core type cable. Further, even if the cable has a round or gourd-shaped cross-sectional shape, the shape of the protective case that covers the outer circumference of the connection portion is similar to the outer shape of the target cable or the like. It can be easily applied by configuring as.

(Fireproof Structure at High Voltage Branch Using L-Type Connector) In addition to the fireproof structure at the connection part of the high voltage fireproof cable as shown in FIG. 1, the fireproof structure of the present invention is shown in FIG.
It can also be applied to a high-voltage branching unit using an L-type connector as shown in FIG. In the example shown in FIG. 5,
With respect to the connecting portion using a general L-type connector, a protective case member 23 having a refractory filling 25 filled therein is attached to the entire outer periphery of the high-pressure branch portion 30, and the entire high-pressure branch portion 30 is fire-resistant. I'm trying to have a sex. In FIG. 5, high-voltage fireproof cables 1, 1
At the connection portion of a, the conductors 2, ... Are connected by the connection conductor 31, and a spacer 32 including an insulating portion 32a and a conductive portion 32b, an insulating portion 33a and an insulating portion including inner and outer conductive portions 33b and 33c. The cylinder 33 is provided, the branch socket 40 is attached to the connection conductor 31, and the ground wire 36 is arranged. In this case, a reinforcing insulator (made of EP rubber) is used as the cylindrical insulating portion 33a of the insulating cylinder 33, and the outer conductive portion 33 integrally molded on the circumference thereof.
An external semiconductive layer (made of conductive EP rubber) can be used as c. In addition, the outer peripheral portions of these members are covered with the conductive tape 34 and the external protective layer 35, and the main body cable side is configured with the branch socket 40 protruding at a right angle.

The L-shaped connector 41 has a connection plug terminal 42 projecting from one end of the main body of the L-shaped connector 41, which is formed in a substantially L-shape, and a branch line on the other side of the main body. The conductor 2b of the high-voltage fireproof cable 1b is attached via the crimp terminal 43. Then, by inserting the connection plug terminal 42 of the L-shaped connector 41 into the branch socket 40 and fixing it, the high-voltage branch section 30 can be configured. In the present invention, the entire outer periphery of the high-pressure branch portion 30 can be covered with the protective case member 23 so as to have fire resistance. Further, as the protective case member 23 and the refractory filling 25 filled in the protective case member 23, those having the properties as shown in the above-mentioned embodiment can be used in combination.

As shown in FIG. 6, the protective case member 23 attached to the high-voltage branching portion 30 as described above covers the main body portion and the outer peripheral portion of the L-type connector by separate members. Can be configured as In the protective case member 23 of the high-voltage branch section 30 shown in FIG. 6, the protective case member 23a arranged on the main body side and the protective case member 23b arranged on the L-shaped connector 41 side are separately configured. , And these are combined in a substantially semi-cylindrical shape so as to cover the outer periphery of the connecting portion. In addition, the connecting portions of the two types of protective case member members 23a and 23b can be made to have a shape in which they are overlapped with each other, so that the fire resistance performance at the connecting portions can be secured.

The high-voltage branch using the L-type connector shown in FIGS. 5 and 6 is for connecting a high-voltage fireproof cable,
Assembly of branch socket 40 and L-type connector 4
1 can be mounted in the same manner as in the case of the conventional high-voltage fireproof cable, and after the connection work, the fireproof filler 25 and the protective case member 23 are provided on the entire outer peripheral portion of the high-voltage branch portion. By constructing, the fire resistance at the high-pressure branch portion can be improved. When removing the L-type connector, the protective case member 23 is removed, the refractory filling is stripped off to expose the high-pressure branch portion, and the same as in the case of the connector member without the protective case member. Construction can be performed in various processes. Further, the connecting means having fire resistance of the present invention is, for example,
In the case of providing a connector, which is almost similar to the connecting portion as shown in Japanese Patent Laid-Open No. 162728, to the high voltage branching portion,
It can be used as a means for maintaining the fire resistance of the high-voltage branch portion, such as a connector portion provided on a flat cable as disclosed in JP-A-2-23015.

(Fireproof structure of cable end portion) When the fireproof structure is applied to a high pressure fireproof cable arranged on an electric shaft of a building or the like, separately from the high pressure branch portion shown in FIG. It is necessary to suspend the upper end of the shaft from the ceiling of the shaft. In that case, in general,
Although the cable is configured to be suspended via insulating glass or the like, in the present invention, the high voltage terminal portion 50 as shown in FIGS. 7 and 8 can be used. The high-voltage terminating portion 50 has a conductor connecting fitting 53 having a T-shaped cross section for suspending a cable conductor through a cable hanging fitting 51 provided with a bolt hole for hanging and an insulating block 52 made of epoxy resin or the like. The direct connector 56 attached to the end of the conductor 2 of the high-voltage fireproof cable 1 is supported (screwed) on the conductor coupling fitting 53.

When the direct connector 56 provided at the end of the high-voltage fireproof cable 1 is connected to the conductor connecting fitting 53, the connecting portion is surrounded by an insulating tube (insulating reinforcement body) 55, and a tightening band is provided. 54 is attached to secure the electric field relaxation and the fixed state of the connection portion. That is, the insulating cylinder 55 is of a premolded type provided with the inner semiconductive layer 55a, the insulating layer 55b, and the outer semiconductive layer 55c. A conductive tape 57 is wound around the lower end of the insulating cylinder 55 so as to be connected to the shield layer of the cable 1, and a ground wire 59 is drawn out. Then, the hanging fitting 51
It can be attached to a support member arranged on the ceiling of the building through the attachment hole provided in, and the high-voltage fireproof cable 1 can be hung and held via the high-voltage terminal portion 50.
It is possible to ensure fire resistance in the high-pressure terminal end portion.

A high voltage terminal section 50 constructed as described above.
In this case, since it is necessary to protect a predetermined section of the hanging metal fitting 51 and the base portion of the high-voltage fireproof cable 1, as shown in the figure, the entire case is covered by a protective case member 24, and the protective case member 24 is covered. The inside of 24 is filled with a refractory filling 25. Further, in the high voltage terminal portion shown in FIG. 7, a protective case member 2 for protecting the outside is provided.
4 can be used in combination with the two split shapes as shown in FIGS. further,
The refractory filler to be filled in the inside of the protective case member may also be configured by attaching it to the outer surface of the main body connecting portion, which is configured by being attached to the inner surface of the protective case member in advance.

In the above embodiment, the protective case member 24
The refractory filling 25 and the refractory filling 25 are, as shown in the above embodiments, a combination of a protective case member having a property of melting at high temperature and a refractory filling having self-hardening property, or a protection having a property of not melting at high temperature. A combination of a case member and a foamable refractory filler, such as a combination of those having arbitrary performance, can be used. And also in the high voltage | pressure termination | terminus part 50 shown by said FIG. 7, 8, the fire resistance with respect to the termination | terminus support part of the high voltage | pressure fireproof cable 1 can be ensured.

(Structure of Power Supply System in Building) The fireproof connection portion of the present invention configured as described above can be applied to a power supply facility of a building as shown in FIG. 9, for example. . In the example shown in FIG. 9, for example, an electric room E is arranged in the basement of the building B, and the high-voltage fireproof cable 1 wired from the electric room E through an electric shaft is used to supply power to each floor. In this embodiment, a high-voltage terminal 50 is arranged on the ceiling of the electric shaft E, and the high-voltage fireproof cable 1 is suspended via the high-voltage terminal 50. Then, the high-voltage fireproof cable 1 can be connected to the transformer P on each floor by using the high-voltage branching section 30, and these high-voltage branching sections can be configured to have an arbitrary power feeding capacity. Further, in the power feeding system in the building of FIG. 9, the high voltage terminal portion as shown in FIG.
In the middle part, a high pressure branching part as shown in FIG. 5 can be used.

Therefore, in the power supply system shown in FIG. 9, a high-voltage fireproof cable can be used as the main cable, and an insulating protective layer of mica tape is provided at the high-voltage fireproof cable portion.
Even if the protective layer of the cable is burned by a fire, the insulation of the conductor can be maintained. On the other hand, in the branch portion of the high-voltage fire-resistant cable, by using the high-voltage branch portion as shown in the drawing, even if a fire-resistant protective layer such as mica tape is not particularly formed around the connector. Even when the connector portion is exposed to a high temperature due to a fire, the insulating state of the connector can be maintained. Furthermore, at the high-voltage termination provided at the top of the high-voltage fireproof cable, the hanging metal fitting and the fixing member on the upper part of the cable are
By covering with a protective member that is a combination of a protective case member and a refractory filling, it is possible to maintain a good insulation state of the high-voltage terminal end even in the case of a fire.

As described above, when constructing a power supply system in a building using the protective member of the present invention, the high-voltage fireproof cable 1 is cut in advance so as to correspond to a predetermined length, and A connector can be attached to the branch of each floor. When the high-voltage fireproof cable 1 is laid, it is pulled into the electric shaft of the building, the uppermost high-voltage terminal end portion 50 is fixedly held on the ceiling support member, and the branch line is connected to the transformer on each floor. I will let you. In addition, when the power receiving capacity at each floor is to be changed while the power feeding system is in use, the high-voltage fireproof cable 1 may be replaced with a cable having a large power feeding capacity, or the branching connector may have a large capacity. Means such as replacement can be applied. For example, even when the connector is replaced with one having a large capacity, in the present invention, the protective case member 23 arranged outside the termination connecting portion as shown in FIG. 5 is removed and the refractory filling is peeled off. Then, remove the connector, attach a large-capacity connector separately, and fireproof the outside.

(Experimental Example 1) The example shown in FIG. 10 is a test method for a fireproof cable according to the Fire Service Agency Notification No. 7 announced on October 16, 1978, and a test applying the test method. An example of the case where it is performed is shown. In the example shown in FIG. 10, a cylindrical protective case member 65 made of aluminum is arranged around the high-voltage fireproof cable 1, and a fireproof filler is filled between the protective case member 65 and the high-pressure fireproof cable. The figure shows the case where the test was performed without the space 67. In addition, the protective case member 65 is the same as the test method according to the above-mentioned notification.
0 is fixed and held by wires 61, 62 and the like at a predetermined interval, and a weight member 63 is suspended at the center thereof to apply a load.

As described above, the high-voltage fireproof cable 1
The test piece with the protective case member 65 covering the
When heating was performed to raise the temperature to 840 ° C. in 0 minutes, the protective case member 65 arranged on the surface of the high-voltage fireproof cable 1 was melted. Then, the insulator layer and the surface coating layer of the high-voltage fireproof cable 1 were all burned, and the conductor 2 covered with the mica tape was exposed to the outside. I was able to secure it. However, as described above, when only the protective case member is simply used, a material that melts at a high temperature, such as aluminum, can protect the high-voltage cable connection portion at all. Turned out not.

(Experimental Example 2) In the example shown in FIGS. 11 and 12, the periphery of the high-voltage fireproof cable 1 is covered with a fireproof filler 66 having a thickness of 6 mm, and a protective case member 65 made of aluminum is provided on the surface thereof. It shows the case where the test piece is used as a test piece. The protective case member 65 is made of the same material as that shown in FIG. 10, and has the same size and the like.
Further, as the refractory filling 66, a material having a property of exhibiting self-hardness when heated to a high temperature, such as DF putty N shown in each of the experimental examples, is used, and the refractory filling is used for a high-voltage fireproof cable. Fill with no gap between the outer surface and the protective case member,
A heating test was performed on the test piece under the same heating conditions as in the case of the above figure.

When the heating test was performed on the test piece as described above, the protective case member 65 did not melt even at 840 ° C., and maintained a substantially cylindrical shape. Further, the outer surface portion of the refractory filling 66 is
Although it was carbonized by heat to form a solidified layer, the inner part in contact with the high-voltage fireproof cable was not deteriorated in its raw state. Furthermore, the outer coating layer of the high-voltage fireproof cable 1 is
The portion covered with the refractory filling did not deteriorate at all, the conductor protection member maintained its state, and the insulation performance did not change. That is, when the external covering means for the high-voltage fireproof cable as shown in FIGS. 11 and 12 is used, for example, even if a protective case member such as aluminum having a property of melting by high heat is used, it is added to the surface thereof. It can be considered that the generated heat is not brought into a state of melting the aluminum member by being absorbed by the refractory filling material inside.

Further, the refractory filling material filled in the protective case member absorbs a large amount of heat due to its thermal alteration, but the thermal conductivity of the refractory filling material is very small, so that the surface of 840 ℃, although only the part is altered by heat
It was found that even if it was heated for about 30 minutes, the refractory filling having a thickness of 6 mm was not deteriorated.
Therefore, when the protective case member and the refractory filling as described above are combined to form a protective member for the high-voltage cable connection part, the high-voltage branch part, etc., even if the connection part is heated at a high temperature due to a fire or the like. , The high-voltage fireproof cable main body can be protected accurately, and the experimental example 1
In this case, only the part covered with the mica tape is not exposed as in the case of.

(Experimental Example 3) The example shown in FIG. 13 is different from the example shown in FIG. 11 in that the amount of the refractory filler 66 is reduced at both ends of the protective case member 65 and the void 68 is formed. It shows the case of forming and testing. Then, when the same heating test as in the case of FIG. 10 was performed on the test piece, in the portion not filled with the refractory filling, the protective case member 65 made of aluminum had about half the gap from the tip portion thereof. Melted in the range. Further, in the melted portion of the protective case member, the surface coating layer and the insulating layer of the high-voltage fire-resistant cable are burned and lost, and the mica tape coating the conductor is exposed.

Therefore, according to the result of the test as shown in FIG. 13, the refractory filling 66 filled inside the protective case member expands by being heated, but along the inside of the protective case member. It can be considered that the high-pressure refractory cable does not significantly expand in the axial direction but expands in the radial direction of the high-pressure refractory cable. And
It can be considered that the heat-insulating action can be strongly exerted by the expansion of the refractory filling between the high-voltage refractory cable and the protective case member.

(Discussion of Experimental Results) As shown in Experimental Examples 1 to 3, when the protective case member is not filled with the refractory filling, or when a large void is left, the aluminum or the like is protected. Although the case member burns out relatively easily, it has been found that the protective case member itself does not burn out due to high heat when the refractory filling is filled between the protective case member and the high-voltage fireproof cable. Therefore, from the results of Experimental Examples 1 to 3, as a protective case member applied to the connection portion of the high-voltage fireproof cable of the present invention,
It is suitable to use a cylindrical member made of aluminum in view of workability and other conditions. Further, in the high-voltage cable connecting portion, the high-voltage branching portion, or the like, as the fire-resistant filling material to be filled between the high-pressure fire-resistant cable and the protective case member, the DF putty N or a material having a property equivalent thereto is used. , It was found that the performance of protecting the connection part can be exhibited satisfactorily.

It should be noted that the results of Experimental Examples 1 to 3 are not sufficient as materials for determining the fire resistance and insulation performance at the connection portion of the high-voltage fire resistant cable, and similar tests are performed on other materials. It is necessary. But,
As can be seen from the above experimental results, in the high-voltage cable connecting portion, the high-voltage branching portion, etc. of the present invention, as the protective case member and the refractory filling material, any one of many materials is selected and used in combination. can do. And even when the connection part of the high-voltage fireproof cable is exposed to high heat,
It is possible to maintain the original shape and insulation of the cable without burning the part protected by the protective case member.

[0042]

As described above, the connection part of the high-voltage fireproof cable of the present invention is
Since it has the above-mentioned structure, it is necessary to ensure the fire resistance of the connecting portion not only when connecting two cables in a straight line but also when processing a branching portion, a terminating portion, etc. You can Further, since only the combination of the fireproof filler and the protective case member is applied to the surface of the connection portion, the fireproof treatment can be easily performed, and the fireproof performance at the high voltage cable connection portion can be easily ensured. be able to. Further, in the fireproof structure of the present invention, a protective case member is formed in advance in a shape corresponding to the application point of the fireproof structure with respect to the connection portion of the high-pressure fireproof cable, the high-voltage branch portion, the high-voltage termination portion, or the like. By doing so, the fireproof treatment with the protective case member and the fireproof filler can be easily performed. In particular, at the branch portion and the like, the covering member such as the protective case member can be easily removed, so that the work of changing the capacity at the branch line can be easily performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram in the case where the fireproofing means of the present invention is applied to a connection portion of a high-voltage fireproof cable.

FIG. 2 is an explanatory diagram of a combined state of protective case members.

FIG. 3 is an explanatory diagram of a combined state of protection case members having another configuration.

FIG. 4 is an explanatory diagram of a combined state of protection case members having other configurations.

FIG. 5 is an explanatory diagram when the fireproofing means of the present invention is applied to a high-pressure branch portion.

6 is an explanatory diagram of a case where the protective case member shown in FIG. 5 is divided and configured. FIG.

FIG. 7 is an explanatory diagram when the fireproofing means of the present invention is applied to a high-voltage terminal end.

FIG. 8 is a vertical cross-sectional view of the high voltage terminal portion shown in FIG.

FIG. 9 is an explanatory diagram showing the arrangement of power supply systems in a building.

FIG. 10 is an explanatory diagram of a performance test of a protective member for a high-voltage fireproof cable and a case where only a protective case member is used.

FIG. 11 is an explanatory diagram of a case where a fireproof test is performed by combining a protective case member and a fireproof filler.

12 is a cross-sectional view of the example shown in FIG.

FIG. 13 is an explanatory diagram of a case where a test is performed with a gap provided at the end of the protective case member.

FIG. 14 is an explanatory diagram of a fireproofing process for a conventional high-voltage fireproof cable.

FIG. 15 is an explanatory diagram of a power feeding system in a building using a conventional high-voltage fireproof cable.

[Explanation of symbols]

1 high-voltage fireproof cable, 2 conductor, 3 insulator, 4 sheath, 5 mica tape, 10 and 10a
High-voltage cable connection part, 11 conductor connection tube, 12
Fireproof layer, 17 Fireproof protective layer, 18 Waterproof tape, 20, 23, 24 Protective case member, 25
Refractory filling, 30 high-voltage branch, 31 connecting conductor,
33 insulating tubes, 40 branch sockets, 41 L
Type connector, 50 high-voltage terminal part, 53 conductor connecting metal fitting, 55 insulating tube, 56 direct type connector, 60
Perlite board, 65 Protective case member, 66
Fireproof filling.

Claims (3)

[Claims] 1. At least reinforcement on an intermediate conductor connecting portion for connecting the cable conductors to each other by a conductor connecting pipe or a plug-lessep method, or on a terminating conductor connecting portion for connecting a cable conductor end to a conductor fitting for suspending a cable conductor. In a connection part of a high-voltage fireproof cable provided with an insulator and an outer semiconductive layer on the periphery thereof, a protective case member is arranged so as to cover the surface of the high-voltage fireproof cable connection part, and the high-voltage fireproof cable connection part A connection part of a high-voltage fireproof cable, characterized in that a fireproof filler having a predetermined thickness is filled between the protective case member and the protective case member. 2. The protective case member is made of a material having a property of being melted by high heat, and a putty member having a property of being hardened at a high temperature is filled between the protective case member and the high-voltage cable connecting portion. The connection part of the high-voltage fireproof cable according to claim 1, wherein 3. The protective case member is made of a material having a property of not melting at a high temperature, and a putty member having a foaming property at a high temperature is filled between the protective case member and the high-voltage cable connecting portion. The connection part of the high-voltage fireproof cable according to claim 1, wherein