JPH06168751A - Junction device for fireproof cable - Google Patents

Abstract

PURPOSE:To substantially improve insulation performance for allowing an application as a high voltage branch section, and further improve reliability and workability by molding a plurality of fireproof cables and the same number of branched connecting conductors altogether with insulation resin. CONSTITUTION:Fireproof cables and branched connecting conductors are arranged by the same number, and the necessity of winding a fireproof tape around a branch section is thereby eliminated. Namely, a fireproof inclusion material 3d is laid in a section where paired connection conductors for branching 1a, 1a, 1b, 1b, 1c, 1c, are set up parallely, on which fireproof insulation layers of such as glass mica tapes 2a, 2b, 2c the number of which is the same as fireproof cables 11a, 11b, 11c to be connected are wound at a factory before hand. Then, a glass mica tape or the like is wound around the section for insulation as a whole. Also, the external surface of the taped section is covered as a whole with insulation mold 4 such as polyethylene and a shield layer 5, and each two of connecting conductor are fitted with compression sleeves 6a, 6b and 6c as a whole. According to this construction, insulation performance can be substantially increased to such an extent as allowing an application as a branch section for high voltage, and workability and reliability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branch portion for a fireproof cable, and more particularly to a branch portion for a fireproof cable having a significantly improved insulation performance.

[0002]

2. Description of the Related Art An example of a conventional branch portion for a fireproof cable will be described with reference to FIG. 3 fireproof cables 210,2
10a and 210b are branched by a T-shaped branch connection fitting 21. At this branch portion, the sheath 29 of the fireproof cable 210 is peeled off to expose the insulator 25, and the insulator 25 is peeled off to expose the fireproof layer 24 on the conductor and the cable conductor 23 to the inside of the sleeve 21a of the branch connection fitting 21. It is configured by inserting and compressing and connecting.
(The other fireproof cables 210a and 210b are also performed in the same manner.) Further, a fireproof tape 22 such as glass mica tape is provided so as to reach the respective fireproof layers 24 while surrounding the exposed portions of the branch connection fitting 21 and each conductor 23. It is wrapped around the outer circumference. Further, an insulating layer 26 is formed on the outer circumference of the branch connection portion, and a waterproof layer 27 for waterproofing the whole is applied to each cable sheath 29 to cover the cable sheath 29.

According to the branch connection portion thus constructed, even if a fire occurs, the waterproof layer 27 and the insulating layer 26 are burnt, but the layer of the fireproof tape 22 made of a refractory material escapes the flameburn. The function as an insulating layer is maintained, and electricity can be supplied for a specified time even after a fire.

[0004]

By the way, according to the above-mentioned branch portion for the fireproof cable, it is very difficult to wrap the fireproof tape around the outer periphery of the branch connection fitting 21 because of the T-shape, and high insulation performance is obtained. Can't get, for example,
There is a problem that it cannot be used as a branch for high voltage exceeding 600V.

In general, since the fireproof tape 22 is a tape such as a glass mica tape having a small elongation, a large gap is formed in the overlapping portion of the tape at a branch portion such as a T-shaped three-pronged portion, which can be used for high voltage. It is difficult to obtain the characteristics. On the other hand, even in the case of a straight or L-shaped branched portion, if it is not branched, it can be wound around a bent portion by reducing the tape width, etc. Have been obtained.

The present invention has been made in view of the above circumstances, and can significantly improve the insulation performance and can be used as a branch portion for high voltage, and further improve reliability and workability. An object of the present invention is to provide a refractory cable branch that can be made.

[0007]

In a branch portion for a fireproof cable in which a plurality of fireproof cables each having a fireproof layer on a conductor are connected via a branch connecting conductor, the number of the connecting conductors is the same as the number of cables to be connected, and A branch connecting device for a fire resistant cable, characterized in that the connecting conductor is insulated with a fire resistant insulating tape and then molded with an insulating resin at once.

[0008]

In order to achieve the above object, for example, if there are three fireproof cables, the number of branch connection conductors should be three. The present invention provides a branch portion for a fireproof cable that does not require winding. That is, the branch portion for a fireproof cable of the present invention is a glass cord to which two connecting conductors for branching, each having the same number of fireproof insulating layers as glass mica tape and the like, are connected in parallel, are connected to the glass cord. Etc., and wrap them all together with glass mica tape etc. to insulate them, and then mold the outer periphery of them all together with an insulator such as polyethylene. It is attached. Then, a fireproof tape such as a glass mica tape is wrapped around the fireproof layer formed by winding the two connection conductors all at once to the fireproof layer on the cable conductor. For this reason, the work of winding the refractory tape around the branch portion is eliminated, and the insulation performance can be greatly improved to be used as a high voltage branch portion. Further, since the tape winding work is reduced, workability and reliability are significantly improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a structure of a branch portion for a fireproof cable according to an embodiment. That is, the branch portion connects the three fireproof cables 11a, 11b and 11c to the branch connection conductors 1a, 1
It is a T (or Y) branch connection part branched at b and 1c. A fireproof insulating layer 2a, 2b and 2c such as glass mica tape is attached to each of the connecting conductors 1a, 1b and 1c in advance at a factory except for the portions that enter the compression sleeves 6a, 6b and 6c. These branch connection conductors 1a, 1
b and 1c form a T-branch portion by combining two linear branch connecting conductors 1a, two inverted U-shaped branch connecting conductors 1b, and two branch connecting conductors 1c formed by combining straight lines and L shapes. is there.

Therefore, these connecting conductors 1a, 1b and 1c are combined so that two of them are parallel to each other toward the fireproof cables 11a, 11b and 11c to be connected, and each parallel portion is shown in FIG. As shown in the sectional view taken along the line A-A 'of FIG. 1, the fireproof insulating layers 3a, 3b and 3c such as glass mica tape are wound together with the interposition 3d such as glass cord. Then, the refractory layer 3a,
3b and 3c are left, and the combined branch connecting conductors are collectively covered with the insulator 4 and the shielding layer 5 such as polyethylene or ethylene propylene rubber, and the two connecting conductors are compressed together. The sleeves 6a, 6b and 6c are attached to form the branch connection part.

Fireproof cables 11a, 11b and 11c
The sheaths 15a, 15b and 15c are stripped off to expose the insulators 14a, 14b and 14c, and further the insulators 14a, 14b and 14c are stripped to remove the fire-resistant layer 13 on the conductor
a, 13b and 13c and conductors 12a, 12b and 1
2c is exposed and inserted into the compression sleeves 6a, 6b and 6c for compression connection.

Subsequently, after the conductors 12a, 12b and 12c of the fireproof cables 11a, 11b and 11c are compression-connected to the compression sleeves 6a, 6b and 6c, the cables are exposed from the exposed portions of the fireproof layers 3a, 3b and 3c of the branch connection portions. Fireproof tapes 7a, 7b and 7c such as glass mica tape are wound around the fireproof layers 13a, 13b and 13c. In addition, insulating layers 8a, 8b and 8c, shielding layers 9a, 9b and 9c, and waterproof layers 10a, 10b and 10c are provided, respectively.

As described above, since the branch connecting conductors are each provided with the fireproof layer and the branch portions are insulated with the mold made of polyethylene or the like, even when the mold insulator such as polyethylene is burned out in normal times and by a fire. Since the refractory layer having high insulation performance remains, it can be sufficiently applied to the high-voltage branch portion. Further, since troublesome work such as tape winding work at the connection site is reduced, work efficiency is improved and reliability can be improved.

In this example, the T (Y) branch is described as an example, but the present invention is not limited to this, and other H type, X
It may be a mold or the like, and can be similarly applied to various branch parts.

[0015]

As described above, according to the branch connecting portion for a fireproof cable of the present invention, the same number of branch connecting conductors as the fireproof cables to be connected each provided with a fireproof layer are collectively molded with polyethylene or the like. Since it is unitized, it can be used as a high-voltage branching portion with a significantly improved insulation performance, and the workability and reliability can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a branch connection device for a fireproof cable according to an embodiment of the present invention,

2 is a cross-sectional view taken along the line AA ′ of FIG.

FIG. 3 is a cross-sectional view showing a configuration of a conventional branch connection device for a fireproof cable.

[Explanation of symbols]

 1a, 1b, 1c Branch connection conductor 2a, 2b, 2c Fireproof layer 3a, 3b, 3c Fireproof layer 3d Fireproof intervening 4 Insulation mold 5 External shield 6a, 6b, 6c Compression sleeve 7a, 7b, 7c Fireproof layer 8a, 8b, 8c Connection part insulating layer 9a, 9b, 9c Connection part shielding layer 10a, 10b, 10c Connection part waterproof layer 11a, 11b, 11c Fireproof cable 12a, 12b, 12c Cable conductor 13a, 13b, 13c Fireproof layer on cable conductor 14a, 14b, 14c Cable insulator 15a, 15b, 15c Cable sheath

Claims (1)

[Claims] 1. In a branch portion for a fire resistant cable in which a plurality of fire resistant cables each having a fire resistant layer on a conductor are connected via a branch connecting conductor, the number of connecting conductors is the same as the number of cables to be connected, and each connecting conductor is fire resistant. A branch connection device for fireproof cables, characterized by being insulated with an insulating tape and then collectively molded with an insulating resin.