JP5664976B2 - Cable connection structure - Google Patents

Description

  The present invention relates to a cable connection portion structure, and more particularly to a cable connection portion structure with improved waterproofness, impact resistance or self-extinguishing properties.

For example, a power supply cable, a communication cable, and the like in a nuclear power plant or the like are installed in a rack in a cave such as underground (see Patent Document 1 FIG. 3).
On the other hand, the cable cannot have a connection portion (seam) over the entire length of the cave, and there are cases where several cables are connected on the rack. The cable connecting portion will be described with reference to FIG. 1 and FIG. 4. Insulating tape 12, cloth tape 13, and waterproof tape 14 are wound around the cable conductor connecting portion in order, and further waterproof. In order to improve, the structure which covered with the waterproof admixture or the rubber putty is common (refer patent document 2 FIG. 1 and patent document 3 FIG. 1).

JP 2000-308247 A Japanese Utility Model Publication No. 64-2498 JP 2001-231149 A

In the state where the cable P is installed in the rack (R in FIG. 1), the cable P on the rack R falls from the rack R when the cave or the rack R is damaged by an earthquake or the like. At this time, when the cable connection portion hits a corner or the like of the rack R, the outermost layer of the connection portion is damaged or damaged by the impact. In addition, concrete or stones in the cave may fall due to an earthquake or the like, and the cable connection part may be damaged or damaged. If the cable connection portion is damaged or damaged, the insulation properties may be deteriorated or destroyed, or water may enter the connection portion, and the cable P may no longer function. Further, in the case of the power cable P, there is a fear that the cable connection portion may be burned due to a ground fault due to breakage or damage of the cable connection portion.
Conventionally, as described above, it is covered with a waterproof admixture or rubber putty to prevent damage or scratches, but it is not sufficient, and the waterproof admixture or rubber putty is not sufficient. There is a problem that construction is complicated. Also, the self-extinguishing property is not sufficient.

  This invention makes it a subject to further improve waterproofness and impact resistance or self-extinguishing property under said actual condition.

In order to achieve the above object, the present invention first focuses on the fact that conventional putty is used as a gap filler. Next, although the putty is inferior in shape retention, its outer peripheral surface is covered with a sheet. For example, paying attention to its shape retention and improved impact resistance, put a putty layer and an impact-resistant protective sheet on the outer peripheral surface of the waterproof tape layer in the conventional cable connection part. It was decided.
If it does in this way, it will become the connection part which improved waterproofness and impact resistance with the putty layer and a protection sheet.

  As a configuration of the present invention, in the cable connection portion structure in which the insulating tape and the waterproof tape are wound around the cable conductor connection portion in order, the waterproof tape layer is covered with a putty and both ends of the waterproof tape layer are covered. It is possible to adopt a configuration in which a putty layer is formed on the waterproof tape layer so as to wrap the cover, and the periphery of the putty layer is covered in a cylindrical shape with an impact-resistant protective sheet.

  With this configuration, both ends of the waterproof tape winding layer that has been exposed in the past are covered with a putty layer, and this putty layer is inferior in shape retention but good formability. The outer peripheral surface of the putty layer can be easily formed as a long cylindrical surface having the same diameter. For this reason, it is easy to cover the protective sheet. Moreover, since the shape retention of the putty layer is ensured by the protective sheet and the impact is further reduced (impact resistance is ensured), there is no abnormality in the performance of the cable conductor connection portion.

At this time, the protective sheet can be self-extinguishing. The self-extinguishing property means “a property that does not burn out even if it is burned if it is a material having an oxygen index greater than the oxygen concentration 21 (volume%) in the atmosphere”. For this reason, if the oxygen index of the protective sheet of the present invention is more than that, for example, 26.8, the protective sheet will not burn out and be damaged even if a fire occurs for some reason. Each covering layer except the protective sheet around the core conductor is not damaged.
Further, if the putty layer has a self-extinguishing property in addition to the inherent waterproofness and impact resistance, the self-extinguishing property of the entire cable connecting portion is further improved.
Furthermore, it is preferable that the cylindrical covering of the protective sheet secures the shape retaining property of the putty layer by fastening and fixing the putty layer and maintaining the tightening and fixing state. In addition, the effect of securing self-extinguishing properties of the cable connection part is not ensured by creating a gap in the overlapping part such as the edge of the protective sheet or a gap between the protective sheet and the putty layer. It is preferable to do. The fastening and fixing may be a well-known means such as a cylindrical cover with a protective sheet, and then bonding and fixing the protective sheets together or the protective sheet and the putty layer with a refractory adhesive or a refractory tape. If a refractory fastening band made of, for example, is wound and fastened, the fastening force can be sufficiently obtained and the fastening and fixing state can be easily maintained.

  Since this invention is comprised as mentioned above, it can be set as the connection part which improved waterproofness and impact resistance or self-extinguishing property in addition to it compared with the past.

Cut front view of one embodiment of the present invention Plan view of the same embodiment Right side view of the same cut Sectional view of the cable connection part of FIG.

  One embodiment is shown in FIGS. 1 to 4, and the 600 V class self-extinguishing (flame retardant) ethylene propylene rubber insulating self-extinguishing (flame retardant) heat-resistant vinyl sheath cable P of this embodiment is also installed on a rack in the tunnel. . A cable P is installed on a hot-dip galvanized cold-rolled steel plate (SPC) receiving tray 1 installed between the rack arms R and R, and the end of the connection portion of the cables P and P is fixed to the receiving pan 1. It is supported and fixed via a bush 3 by a bracket 2 made of a galvanized cold rolled steel plate. The bush 3 is made of flame retardant rubber or the like.

  The sheath of the cables P and P is peeled off to expose each core wire p, the twisted core wire p is unwound, the insulation coating at each end is stripped, and the conductor 10 is exposed. As shown in FIG. 4, the exposed conductors 10, 10, and 10 are connected to each other by a compression type conductor connecting pipe 11. First, an insulation tape 12 (for example, adhesive polyethylene tape) is wound around each core wire p over the compression-type conductor connecting tube 11 and the ends of the core wires p on both sides thereof, and the three core wires p are wound. A cloth (cotton) tape 13 and a waterproof tape 14 (for example, “Barco Tape”, Furukawa Electric Co., Ltd., trade name: registered trademark) are wound around the outer peripheral surface in order (see FIG. 4). The configuration so far is the same as the conventional one.

In this embodiment, a non-curable putty 15 such as EM-Bubble S (trade name of Tatsuta Electric Wire Co., Ltd., Bab Seal: registered trademark) shown in Table 1 below is further formed on the wound layer of the waterproof tape 14. The outer peripheral surface of the putty layer 15 is covered with a self-extinguishing protective sheet 16 of chloroprene rubber, which is an elastic body shown in Table 2 below, and the protective sheet 16 is fastened and fixed by a stainless fastening band 17 In order to prevent the effects such as self-extinguishment of the cable connecting portion from being reduced due to a gap in the overlapping portion such as the end of the protective sheet 16 or a gap between the protective sheet 16 and the putty layer 15, That is, an effect such as self-extinguishing property of the cable connecting portion is ensured.
Furthermore, since the non-curing putty 15 can ensure impact resistance, both the chloroprene rubber protective sheet 16 and the putty layer 15 can further increase impact resistance and self-extinguishing properties.
In consideration of impact resistance, the hardness of the protective sheet 16 (JISK6253 type A durometer) is preferably A60 or more.

  The putty layer 15 extends over the entire length of the wound layer of the waterproof tape 14, and both ends of the waterproof tape wound layer 14 are not exposed (so that both ends of the waterproof tape layer 14 are covered with the putty 15). Formed). Since the putty 15 is non-curable and has good moldability, the putty 15 can be easily along the outer peripheral surface of the waterproof tape layer 14 with unevenness, and the outer peripheral surface of the putty layer 15 is also easily formed into a long cylindrical shape having the same diameter. Can do. For this reason, it is easy to cover the protective sheet 16, and the protective sheet 16 has a half-cylindrical shape, is cylindrical, has one cut in the entire length in the cylinder axis direction, or is wrapped in a rectangular shape. Can be coated. The number of coatings (number of layers) is arbitrary, such as 1, 2, 3 or the like.

In the conventional cable connection part structure of about 600V class, since the waterproof sheet 14 is the outermost layer, if a fire occurs for some reason, the waterproof sheet 14 may burn out. The cable connection part structure of this embodiment The putty layer 15 is non-curing and has impact resistance and is self-extinguishing. Further, since the protective sheet 16 is also impact resistant and self-extinguishing, it continues to burn even if a fire or the like occurs. Even if the cable P falls from the rack and hits the rack member due to an earthquake or the like, there is very little risk of damage, and the cable connection portion burns due to a ground fault caused by breakage or damage. But there is no fear of burning.
Therefore, when the cable connection portion of this embodiment was tested according to JCAA A 101 and the explanation of technical standards for electrical appliances (Appendix Table 23), the performance shown in the following Table 3 described in the Appendix Table was obtained. I was satisfied enough. The “impact resistance” in the present invention means that the performance is exhibited in the impact test shown in Table 3.

Of course, the present invention is not limited to the newly installed cable connecting portion, but can be applied to the case where the existing cable P and the newly installed cable P are connected or the existing cable connecting portion is modified. Moreover, although the said embodiment was the case of the 3-core cable P, it cannot be overemphasized that this invention can be employ | adopted also in a single-core cable or a multi-core cable of 2 cores, 4 cores or more. At this time, the cloth tape 13 is used for holding the core wire p, and is usually necessary for fixing the cable connecting portion of two or more cores. Of course, it can be omitted in the case of a single-core cable. Even if there are two or more cores, the cloth tape 13 can be omitted if the waterproof tape 14 has a function of fixing the cable connecting portion (a function of pressing the core wire p).
Further, the present invention is not limited to the 600V class low voltage cable P, but can be applied to lower voltage cables or higher voltage cables, and also to communication cables other than power cables. Can do.

P Cable p Cable core 10 Cable conductor 12 Insulating tape (layer)
13 Cloth tape (layer)
14 Waterproof tape (layer)
15 Putty (layer)
16 Protective sheet 17 Stainless steel fastening band

Claims (3)

In the cable connection part structure in which the insulating tape (12) and the waterproof tape (14) are wound around the cable conductor connection part in order, the non-hardening putty (15) surrounds the waterproof tape layer (14). its covering both ends to enclose the waterproof tape layer (14) putty layer (15) formed in the waterproof tape layer (14) on, the protection sheet (16) around its putty layer (15) covers Covered in a cylindrical shape , the protective sheet (16) is fastened by fastening a fire-resistant fastening band (17) around its outer peripheral surface, and the protective sheet (16) has a hardness of A60 or more and is impact-resistant. Self-extinguishing cable connection structure. The cable connecting portion structure according to claim 1, wherein the protective sheet (16) is chloroprene rubber. The cable connection part structure according to claim 1 or 2 , wherein the putty layer (15) is self-extinguishing.

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