JPH0546171Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a flat fireproof cable.

[Background of the idea] As the main line of an indoor power distribution system in a high-rise building, multiple stranded conductors are closely arranged in a horizontal row.
Rubber/plastic insulated flat cables are widely used, which are formed by covering the outside of these cables with a common insulating layer and applying a sheath on the insulating layer.

On the other hand, when a fire breaks out in a building, etc., it is important to ensure the insulation of cables for as long as possible after the fire has broken out.
Or it is essential to maintain the operating power of the alarm device. However, the current situation is that a flat trunk cable with excellent fire resistance has not yet been proposed.

Therefore, as a flat cable that meets such requirements, a structure can be considered in which a fireproof layer is provided on each stranded conductor, and a common insulating layer is coated on top of the fireproof layer. With this configuration, even if the insulating layer burns and disappears in the event of a fire, the fireproof layer will protect the
It becomes possible to temporarily maintain a predetermined insulation property for a certain period of time. However, in the above structure, each stranded conductor deforms separately (wavy deformation) at the stage when the insulating layer burns out, so that the state in which the stranded conductors are closely arranged in a horizontal row is disturbed. Possible causes of the waving deformation include release of the residual stress due to disappearance of the insulating layer, which is a medium for restraining the residual stress held by each stranded wire conductor, and thermal expansion of the stranded wire conductor due to fire heat. If each stranded conductor becomes wavy and deformed separately, the fireproof layers on the stranded conductors will rub against each other, causing the fireproof layer to deteriorate, or the stranded conductor will collide with the cable rack or support material, causing the fireproof layer to break. This may cause early deterioration of the insulation retention properties of the fireproof layer. As a result, the wavy deformation of the stranded conductor reduces the fire resistance performance of the flat cable.

[Means for solving the problem] The present invention was made in view of the above points, and aims to provide a flat fire-resistant cable that suppresses waving deformation of the stranded conductor and further improves fire-resistant performance. The gist is that a flat conductor group 1 in which a plurality of stranded conductors 10 provided with a fireproof layer 2 are closely arranged in a horizontal row is coated with an insulating layer 4 common to each stranded conductor 10. This flat fireproof cable is characterized in that a fireproof tape 3 is wound directly above the conductor group 1.

[Function] By providing a fireproof layer on the stranded conductor,
Even if the insulating layer burns and disappears in the event of a fire, it is possible to temporarily maintain a predetermined level of insulation for a certain period of time. Furthermore, by wrapping a fireproof tape over the conductor group, the stranded wire conductors of the conductor group are restrained by the fireproof tape in a state in which the stranded wire conductors are closely arranged in a horizontal row, and waving deformation of each stranded wire conductor can be prevented.

[Example] The present invention will be described in more detail below based on the drawings.

FIG. 1 is a sectional view showing an embodiment of the flat fireproof cable 6 of the present invention. In the figure, 10 is a twisted wire conductor (which may be twisted in the same direction or alternately twisted in each layer), and can also be a compressed conductor.
2 is a fireproof layer coated on the stranded wire conductor 10;
A wrapping layer such as film mica or glass mica tape can be used. 1 is a conductor group formed by arranging a plurality of stranded wire conductors 10 coated with a fireproof layer 2 closely in a horizontal line. Further fireproof tape 3 is placed on conductor group 1.
is wound. As the fireproof tape 3, film mica, glass mica tape, etc. may be used as in the case of the fireproof layer 2 described above. Reference numeral 4 denotes a rubber or plastic insulation layer, such as a polyethylene insulation layer, which is extruded and coated after the fireproof tape 3 is wound around the conductor group 1. Reference numeral 5 denotes a cable sheath coated on the insulating layer 4, which can be made of plastic such as flame-retardant vinyl chloride or non-halogen flame-retardant polyolefin.

The fire-resistant tape 3 can be wound around the conductor group 1 by a method such as gap winding, lap winding, cross winding, butt winding, etc. Of course, these may be single winding or multiple winding, as long as they restrain the conductor group 1. Among the above winding methods of the fire-resistant tape 3, the gap winding shown in Fig. 2 is preferred. If the gap winding is used, the valleys 1 between adjacent stranded conductors 10 are not filled.
The insulator penetrates into the insulating layer 4.
The stranded conductor 10 is well restrained by the tape width of about 10 to 60 mm, and the gap width is about 1 to 1/2 the tape width.
By winding the fire-resistant tape 3 around the conductor group 1 in this manner, the valleys 11 can be filled with the insulator satisfactorily.

Figure 3 shows the flat fireproof cable 6 of the present invention in three phases.
It is a figure which shows the usage state in the case of using for a core line.
Needless to say, one flat fireproof cable 6 is used as an in-phase cable. By using three flat fireproof cables 6 of R phase, S phase, and T phase, it can be applied to, for example, a large-capacity, low-voltage trunk line for power supply in high-rise buildings, etc. In this case, since the cable has a flat shape, the impedance is low and the installation space can be reduced, making it suitable for application of the flat fireproof cable 6 of the present invention.

[Effects] As detailed above, in the flat fireproof cable of the present invention, even if the insulation layer burns out in the event of a fire, the conductor group is restrained by the fireproof tape, so each stranded conductor will not wave and deform separately. Therefore, even in the event of a fire, it is useful because it can extend the period of time the fireproof layer retains its insulation properties.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the flat fireproof cable of the present invention, Fig. 2 is a perspective view showing an example of a method of winding fireproof tape, and Fig. 3 is a use of the flat fireproof cable of the present invention. It is a perspective view showing a state. 1... Conductor group, 10... Stranded wire conductor, 2... Fireproof layer, 3... Fireproof tape, 4... Insulating layer.

Claims (1)

[Scope of utility model registration request] Each stranded conductor 1 is placed on a conductor group 1 in which a plurality of stranded conductors 10 provided with a fireproof layer 2 are closely arranged in a horizontal row.
A flat fireproof cable comprising a flat cable coated with a common insulating layer 4, characterized in that a fireproof tape 3 is wound directly above the conductor group 1.