JPH07227032A - Connection for high-voltage fireproof cables - Google Patents

Abstract

(57) [Summary] [Objective] To provide an improved connection portion of a high-voltage fireproof cable. [Structure] When connecting high-voltage fireproof cables with fireproof layers on the conductors, connect the conductors with a conductor connecting pipe, wrap a fireproof insulating tape around each cable fireproof layer, and further sticky polyethylene tape, etc. After electrically insulating the connection part by winding, a metal tape that melts at high temperature is wound around the cable shielding copper tape between the respective cables, and between each cable shielding copper tape is outside the connection part. It was composed by connecting with a metal that did not melt at the high temperature that was pulled out. Further, as the metal wound around the outer periphery of the insulator of the connection part, a metal that melts at a temperature of about 200 ° C. to 400 ° C. is used, and the metal that is drawn out of the connection part and bonded between the respective cable shielding copper tapes is 1000 ° C. Use a metal wire that does not melt within the temperature range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a straight line connection or a branch connection of high-voltage fireproof cables.

[0002]

2. Description of the Related Art FIG. 5 shows a structure of a straight connecting portion of a conventional high-voltage fireproof cable which is generally adopted. That is, for the left and right high-voltage fireproof cables 1 and 1'to be connected, the cable ends on the connection side are stripped off to expose the cable conductors 11, the cable conductors 11 are abutted against each other, and the conductor connection pipes 21 are covered and pressure-welded. To connect. Next, a mica glass tape is wound around the outer periphery of the conductor connecting pipe 21 over each fire resistant layer of the fire resistant cable to form a fire resistant layer 22, and an adhesive polyethylene tape is wound around this outer periphery of each of the high pressure fire resistant cables. A main insulator layer 23 is formed over the insulator 13. Further, a flat braided copper wire 27 is longitudinally provided on the outer periphery thereof, and a non-melting metal shielding layer in which a tin-plated copper wire 28 is roughly wound is provided on each of the shielding copper tapes 1 of the high-voltage fireproof cable.
4, and the protective layer 25 is provided on the outer periphery of the protective layer 25 with an adhesive polyethylene tape or the like to form the connecting portion. In addition, 15 is a vinyl sheath of each high-voltage fireproof cable.

[0003]

Generally, the connecting portion of a cable is more likely to be a weak point than the electric and mechanical characteristics of the cable itself. Especially for high-voltage fireproof cables, 66
Since a high voltage of 00V is applied, a copper tape is wound around the outer circumference of the insulating layer of the cable for electrical shielding, and this is always grounded and used.

In this fireproof cable, when a fire occurs, the sheath material such as polyvinyl chloride (PVC) and the insulating layer such as cross-linked polyethylene are burnt out, but the fireproof layer such as mica glass provided on the cable conductor causes the conductor to disappear. It is designed to electrically withstand between the and the shielding copper tape for the required time.

The cable connecting portion also needs to have characteristics equivalent to those of the cable, but the connecting portion of the conductor is not smooth and has projections or steps. A mica glass tape is generally used as the fire resistant layer for forming the conductor connecting portion, but this has no elongation, is difficult to wind when forming the fire resistant layer, and tends to have inferior properties as compared with the cable. In the combustion test at the time of fire occurrence, when the adhesive polyethylene tape, which is the main insulator of the connection part, has burnt and disappeared, the electrical insulation between the conductor and the shield is the fire resistance applied to the conductor connection part described above. Since it depends 100% on the layer, the fire resistance property depends on the condition of the fire resistant layer of the connection portion. Therefore, the fire resistance characteristics of the connection portion are inevitably unstable, and in the worst case, the desired fire resistance characteristics may not be obtained.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and it is possible to eliminate the instability of the fire resistance performance of the connecting portion and reliably maintain the fire resistance performance. The purpose is to provide a connection part of.

[0007]

The present invention relates to the connection of high-voltage fireproof cables having a fireproof layer on a conductor, the conductors are connected by a conductor connecting pipe, and the fireproof insulation is provided around the outer periphery of each cable fireproof layer. After winding the tape, further winding an adhesive polyethylene tape etc. to electrically insulate the connection part, and winding a metal tape that melts at high temperature around each outer periphery between the cable shielding copper tapes, and,
A high-voltage fireproof cable connecting portion is characterized in that the respective cable shielding copper tapes are connected by a metal that is drawn out of the connecting portion and does not melt at high temperature. Moreover, as the metal wound around the outer periphery of the insulator of the connection portion, 200 ° C. to 4 ° C.
A metal that melts at about 00 ° C. is used, and a metal that does not melt within 1000 ° C. is used as a metal that is drawn out of the connection portion and bonded between the cable shielding copper tapes.

[0008]

[Operation] By using a metal, such as lead tape, that melts together when the protective layer or insulating layer burns out due to the combustion temperature during a fire, as a shielding layer applied to the outer periphery of the insulator at the cable connection The electrical insulation inside can be maintained. In addition, by pulling out from one cable shielding copper tape to the outside of the cable connection part and splicing and bonding to the other cable shielding copper tape, a metal that does not melt during combustion, for example, a copper wire that is connected even during combustion This means that the shielding copper tape of is surely grounded.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a high-voltage fireproof cable connection portion of the embodiment. Similar to the conventional example described above,
The left and right high-voltage fireproof cables 1 and 1'to be connected are stripped off at their ends to expose the cable conductor 11, the cable fireproof layer 12, the insulator 13, and the shielding copper tape 14, respectively, and the cable conductor is placed inside the conductor connecting pipe 21. The 11 parts are abutted against each other and pressed to be connected. Next, a mica glass tape is wound between the cable refractory layers 12 to form the connection refractory layer 22. Further, an adhesive polyethylene tape is wound over the fireproof layer 22 and the respective cable insulators 13 to form the connection portion main insulator 23.

The process up to this point is the same as the method of the prior art described above, but the outer circumference of the connection main insulator 23 is melted by the heat at the time of the fire between the respective cable shielding copper tapes 14 such as lead tape. Wrap the metal 24 of
An electrical shield layer for the connection is provided. Moreover, the metal 2 which is not melted by the heat of the fire from the one cable shielding copper tape 14
6. For example, a copper wire is pulled out of the connecting portion and joined to the other cable shielding copper tape 14. The bond connecting wire 26 has a cross-sectional area suitable for the ground current. Finally, a protective layer 25 is formed as an outer layer of the entire connecting portion by using an adhesive polyethylene tape or the like to configure the connecting portion.

Since the fire resistant cable maintains its performance as an emergency power source especially in the event of a fire, it may not be energized at all times and may be installed as a backup line. Naturally, this fire resistant cable is used. A cable that is always energized and that works as an emergency in the event of a fire was required, but the fire resistant cable of this example is an excellent fire resistant cable connection that satisfies these conditions.

Although the above example describes the case of the straight connection of the high-voltage fireproof cable, the Y-branch and the T-branch can be connected by the same means. Further, the connecting portion is generally a grounding body at a place where it is installed, for example, a rack or the like, and the conductor connecting portion needs to be at least floating from the rack or the like at the time of combustion. An example in which this is actively taken will be described with reference to FIG. In FIG. 2, the connecting portion 2 is supported from the grounding body 3 by the fireproof spacer 4, and the connecting portion 2 is floating.

For the same purpose, in the example shown in FIG.
A fireproof insulating plate 41 such as a mica laminated plate is provided on top of which the connecting portion 2 is installed. Further, as shown in FIG. 4, the rack horizontal bar 31 corresponding to the cable connecting portion 2 may be floated by interposing a fireproof insulating coating 42 around which a mica sheet is wound, for example.

FIG. 6 shows the JIS-A1 used in the combustion test.
3 shows a fire temperature curve for 304. The metal applied to the inside of the cable connection part should be a metal that melts at a temperature of about 200 to 400 ° C like lead tape, and at least the fire temperature should be used as the metal that draws out of the connection part and connects the shielding copper tapes of both cables. A metal that does not melt within 840 ° C. shown in the curve and withstands a temperature of about 1000 ° C. or higher, such as copper, is used.

[0015]

As described above, the connection portion for a high-voltage fireproof cable of the present invention has the following excellent actions and effects and becomes a reliable connection portion with stable characteristics. During normal use, the charging current at the cable connection is
The metal that melts at high temperature inside the connection receives this, and the ground current of the entire cable is made to flow by the metal that does not melt at high temperature provided outside the connection. When the protective layer of the cable connection and the main insulator burn out and disappear due to the high temperature at the time of a fire, the shielding metal in the connection also melts and disappears, so the fireproof layer applied on the conductor connection does not disappear. Even if it is imperfect, electrical insulation is maintained because there is no grounding body near the conductor connection. Even if the shielding layer inside the connection part disappears due to the fire, the metal that does not melt at high temperature provided outside the connection part connects the cable shielding copper tapes, and it is completely grounded even during combustion, so in a place where there is no fire The cable characteristics of will not be impaired.

[Brief description of drawings]

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

FIG. 2 is a side view showing a state in which the installation surface supports and supports the connection portion for the high-voltage fireproof cable with a spacer;

FIG. 3 is a side view showing a state in which a fireproof insulating plate is interposed between the installation surface and the connection portion for the high-voltage fireproof cable.

FIG. 4 is a side view showing an example in which a structure on the installation surface is coated with a fireproof insulating material,

FIG. 5 is a cross-sectional view showing the configuration of a conventional high-voltage fireproof cable connecting portion,

FIG. 6 is a fire temperature curve diagram defined in JIS-A1304.

[Explanation of symbols]

 1,1 'High-voltage fireproof cable to be connected 11 Conductor of high-voltage fireproof cable 12 Fireproof layer of high-voltage fireproof cable 13 Insulator of high-pressure fireproof cable 14 Shielding copper tape of high-pressure fireproof cable 15 Sheath of high-pressure fireproof cable 2 Connection of high-pressure fireproof cable 21 Conductor Connection Tube 22 Fireproof Layer 23 Main Insulator 24 Metal Shielding Layer 25 Protective Layer 26 Ground Bond Wire 27, 28 Metal Shielding Layer 3 Installation Surface 4 Spacer 41 Fireproof Insulating Plate 42 Fireproof Insulating Coating

Claims (2)

[Claims] 1. When connecting high-voltage fireproof cables having fireproof layers on the conductors, the conductors are connected by a conductor connecting pipe, and a fireproof insulating tape is wound around the respective cable fireproof layers, and further, adhesive polyethylene is used. After winding a tape etc. to electrically insulate the connection part, a metal tape that melts at high temperature is wound around the outer periphery of each cable shielding copper tape, and the connection part between each cable shielding copper tape A connection part for a high-voltage fireproof cable, which is constructed by connecting with a metal that does not melt at high temperature that is drawn out. 2. A metal which is melted at about 200 ° C. to 400 ° C. is used as a metal wound around the outer periphery of the insulator of the connecting portion, and a metal which is drawn out of the connecting portion and bonded between the respective cable shielding copper tapes is 1000. The connection part for a high-voltage fireproof cable according to claim 1, wherein a metal wire that does not melt within a temperature range of 0 ° C is used.