Fire resistant cable
A fire resistant cable comprising a conductor and a sheath surrounding the conductor, the cable is characterized in further comprising: a bedding filler arranged between the conductor and the sheath and made of materials providing fire resistance; and, a tunnel filler arranged between the conductor and the sheath in the longitudinal direction of the cable, and having a melting point lower than the combustion point of the bedding filler.
1. A fire resistant cable comprising:
a conductor and a sheath surrounding the conductor;
a bedding filler arranged between the conductor and the sheath and made of materials providing fire resistance; and
a tunnel filler arranged between the conductor and the sheath in the longitudinal direction of the cable, and having a melting point lower than the combustion point of the bedding filler, wherein the tunnel filler is made of a plurality of strings,
wherein the tunnel filler has a melting point of at least 1.5 times smaller than the combustion point of the bedding filler.
2. The fire resistant cable according to claim 1 , wherein the tunnel filler is arranged on either side of the bedding filler or embedded in the bedding filler.
3. The fire resistant cable according to claim 1 , wherein an insulator is provided around the conductor for electrical insulation.
4. The fire resistant cable according to claim 3 , wherein the tunnel filler is arranged between the insulator of the conductor and the sheath.
5. The fire resistant cable according to claim 3 , wherein the insulator is surrounded by a semi-conductive filler and by a shield.
6. The fire resistant cable according to claim 5 , wherein the tunnel filler is arranged between the shield of the conductor and the sheath.
7. The fire resistant cable according to claim 1 , wherein the tunnel filler is made by extrusion of polypropylene or polyethylene.
8. The fire resistant cable according claim 1 , wherein the bedding filler is made of a composition comprising polymer resin and fire resistant additive.
9. The fire resistant cable according to claim 8 , wherein the polymer resin is silicone resin.
10. The cable fire resistant cable according to claim 8 , wherein the fire resistant additive is at least one of silica, mica powder and glass powder.
11. The fire resistant cable according to claim 1 , wherein the bedding filler is made of ceramifiable compound which is changed to ceramic as the temperature increases and becomes a fire resistant barrier.
12. The fire resistant cable according to claim 1 , wherein the conductor is configured to a plurality of conductors that are electrically isolated from each other, and the plurality of conductors has a common insulator.
13. The fire resistant cable according to claim 1 , wherein the tunnel filler melts before the bedding filler's combustion so as to provide air tunnel in the cable.
14. The fire resistant cable according to claim 1 , wherein the tunnel filler is arranged all around the conductor.