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GB2050041A - Fire resistant cable - Google Patents

Fire resistant cable Download PDF

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Publication number
GB2050041A
GB2050041A GB7918768A GB7918768A GB2050041A GB 2050041 A GB2050041 A GB 2050041A GB 7918768 A GB7918768 A GB 7918768A GB 7918768 A GB7918768 A GB 7918768A GB 2050041 A GB2050041 A GB 2050041A
Authority
GB
United Kingdom
Prior art keywords
layer
cable
laminate
earth wire
polymeric composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB7918768A
Other versions
GB2050041B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pirelli General Cable Works Ltd
Pirelli General Cable Works
Original Assignee
Pirelli General Cable Works Ltd
Pirelli General Cable Works
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pirelli General Cable Works Ltd, Pirelli General Cable Works filed Critical Pirelli General Cable Works Ltd
Priority to GB7918768A priority Critical patent/GB2050041B/en
Priority to BR8003364A priority patent/BR8003364A/en
Publication of GB2050041A publication Critical patent/GB2050041A/en
Application granted granted Critical
Publication of GB2050041B publication Critical patent/GB2050041B/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00Insulated conductors or cables characterised by their form
    • H01B7/17Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/29Protection against damage caused by extremes of temperature or by flame
    • H01B7/295Protection against damage caused by extremes of temperature or by flame using material resistant to flame
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00Insulated conductors or cables characterised by their form
    • H01B7/02Disposition of insulation
    • H01B7/0208Cables with several layers of insulating material

Landscapes

  • Insulated Conductors (AREA)

Abstract

In a multi-core electric cable, each conductor is provided with a layer of inorganic material (for example comprising tapes of sheet material consisting of mica paper supported on an open weave glass fabric) which forms a carbon-free insulating layer on combustion, and further with a layer of elastomer- based insulating compound (for example ethylene-propylene based rubber) over the inorganic- material layer. The conductors, together with a bare earth wire, are enclosed within a sheath comprising a laminate of thermoplastic polymeric composition/metal foil and an extruded sheathing of a polymeric composition around the laminate, the metal layer of the laminate facing inwards and contacting the earth wire throughout the cable length. On exposure to fire, the ethylene propylene rubber is destroyed but the mica paper remains intact to maintain adequate electrical resistance between the conductors.

Description

SPECIFICATION Fire resistant cable This invention relates to an electric cable having good fire resistant properties.
This invention is a modification of or improvement in the invention which is the subject of our British patent 1 500 1 21.
Our British patent 1 500 121 describes and claims a multi-core electric cable, which comprises two or more electric conductors, each of which is insulated with a coating of silicone rubber insulation, a bare earth wire, and a sheath consisting of a laminate of a thermoplastic polymeric composition/aluminium or copper foil and an extruded sheathing of a fire retardant polymeric composition around the laminate, the sheath enclosing the insulated conductors and the earth wire with the metal layer of the laminate on the inside and in contact with the earth wire throughout the length of the cable. Such cable construction is suitable for cables in which the cross-sectional area of each conductor is up to 4 square millimetres and which comprises from 2 to 1 9 separate conductors.By way of example, such cable may be used for 2 and 5 pair 0.5 mm2 telephone and signal cables for use in high fire risk areas, such as in power stations, and is suitable for surface mounting.
The present invention provides a multi-core electric cable, which comprises two or more electric conductors, each provided with a layer of an inorganic material which forms a carbon-free insulating layer on combustion and provided with a layer of elastomer based insulating compound over said inorganic material layer, a bare earth wire, and a sheath consisting of a laminate of a thermoplastic polymeric composition/metal foil and an extruded sheathing of a polymeric composition around the laminate, the sheath enclosing the insulated conductors and the earth wire with the metal layer of the laminate on the inside and in contact with the earth wire throughout the length of the cable. The metal foil may comprise aluminium, copper, steel or other suitable metal.The extruded sheathing of polymeric composition will generally be fire retardant, but this may not always be necessary, particularly when the foil metal is steel.
The layer of organic material forming a carbon-free insulating layer on combustion preferably comprises tapes of a sheet material consisting of mica paper supported on an open weave glass fabric, which tapes are wound spirally around each conductor with a suitable overlap, or longitudinally formed around the conductor. The elastomer based insulating compound layer preferably comprises an extruded layer of ethylene-propylene based rubber insulation. Other materials such as cross-linked polyethylene, butyl rubber or thermoplastic rubber may be used provided that the layer has the required electrical properties, moisture resistance necessary to protect the mica paper from a deterioration of its own electrical resistance, and mechanical properties to cushion the mica-paper tapes. Mica paper supported on open weave glass fabric is available commercially.
When exposed to fire, the ethylene propylene rubber is destroyed but the mica paper remains intact and maintains adequate electrical resistance between adjacent conductors.
1. A multi-core electric cable, which comprises two or more electric conductors, each provided with a layer of an inorganic material which forms a carbon-free insulating layer on combustion and provided with a layer of elastomer-based insulating compound over said inorganic material layer, a bare earth wire, and a sheath comprising a laminate of a thermoplastic polymeric composition/metal foil and an extruded sheathing of a polymeric composition around the laminate, the sheath enclosing the insulated conductors and the earth wire with the metal layer of the laminate on the inside and in contact with the earth wire throughout the length of the cable.
2. A cable as claimed in claim 1, in which the extruded sheathing of polymeric composition is fire retardant.
3. A cable as claimed in claim 1 or 2, in which the layer of an inorganic material on each conductor comprises tapes of a sheet material comprising mica paper supported on an open weave glass fabric.
4. A cable as claimed in any preceding claim, in which the elastomer-based insulating compound layer on each conductor comprises an extruded layer of ethylene-propylene based rubber insulation.
5. A cable as claimed in any one of claims 1 to 3, in which the elastomer-based insulating compound layer on each conductor comprises cross-linked polyethylene, butyl rubber or thermoplastic rubber.
6. A multi-core electric cable as claimed in claim 1 and substantially as herein described.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fire resistant cable This invention relates to an electric cable having good fire resistant properties. This invention is a modification of or improvement in the invention which is the subject of our British patent 1 500 1 21. Our British patent 1 500 121 describes and claims a multi-core electric cable, which comprises two or more electric conductors, each of which is insulated with a coating of silicone rubber insulation, a bare earth wire, and a sheath consisting of a laminate of a thermoplastic polymeric composition/aluminium or copper foil and an extruded sheathing of a fire retardant polymeric composition around the laminate, the sheath enclosing the insulated conductors and the earth wire with the metal layer of the laminate on the inside and in contact with the earth wire throughout the length of the cable. Such cable construction is suitable for cables in which the cross-sectional area of each conductor is up to 4 square millimetres and which comprises from 2 to 1 9 separate conductors.By way of example, such cable may be used for 2 and 5 pair 0.5 mm2 telephone and signal cables for use in high fire risk areas, such as in power stations, and is suitable for surface mounting. The present invention provides a multi-core electric cable, which comprises two or more electric conductors, each provided with a layer of an inorganic material which forms a carbon-free insulating layer on combustion and provided with a layer of elastomer based insulating compound over said inorganic material layer, a bare earth wire, and a sheath consisting of a laminate of a thermoplastic polymeric composition/metal foil and an extruded sheathing of a polymeric composition around the laminate, the sheath enclosing the insulated conductors and the earth wire with the metal layer of the laminate on the inside and in contact with the earth wire throughout the length of the cable. The metal foil may comprise aluminium, copper, steel or other suitable metal.The extruded sheathing of polymeric composition will generally be fire retardant, but this may not always be necessary, particularly when the foil metal is steel. The layer of organic material forming a carbon-free insulating layer on combustion preferably comprises tapes of a sheet material consisting of mica paper supported on an open weave glass fabric, which tapes are wound spirally around each conductor with a suitable overlap, or longitudinally formed around the conductor. The elastomer based insulating compound layer preferably comprises an extruded layer of ethylene-propylene based rubber insulation. Other materials such as cross-linked polyethylene, butyl rubber or thermoplastic rubber may be used provided that the layer has the required electrical properties, moisture resistance necessary to protect the mica paper from a deterioration of its own electrical resistance, and mechanical properties to cushion the mica-paper tapes. Mica paper supported on open weave glass fabric is available commercially. When exposed to fire, the ethylene propylene rubber is destroyed but the mica paper remains intact and maintains adequate electrical resistance between adjacent conductors. CLAIMS
1. A multi-core electric cable, which comprises two or more electric conductors, each provided with a layer of an inorganic material which forms a carbon-free insulating layer on combustion and provided with a layer of elastomer-based insulating compound over said inorganic material layer, a bare earth wire, and a sheath comprising a laminate of a thermoplastic polymeric composition/metal foil and an extruded sheathing of a polymeric composition around the laminate, the sheath enclosing the insulated conductors and the earth wire with the metal layer of the laminate on the inside and in contact with the earth wire throughout the length of the cable.
2. A cable as claimed in claim 1, in which the extruded sheathing of polymeric composition is fire retardant.
3. A cable as claimed in claim 1 or 2, in which the layer of an inorganic material on each conductor comprises tapes of a sheet material comprising mica paper supported on an open weave glass fabric.
4. A cable as claimed in any preceding claim, in which the elastomer-based insulating compound layer on each conductor comprises an extruded layer of ethylene-propylene based rubber insulation.
5. A cable as claimed in any one of claims 1 to 3, in which the elastomer-based insulating compound layer on each conductor comprises cross-linked polyethylene, butyl rubber or thermoplastic rubber.
6. A multi-core electric cable as claimed in claim 1 and substantially as herein described.
GB7918768A 1979-05-30 1979-05-30 Fire resistant cable Expired GB2050041B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB7918768A GB2050041B (en) 1979-05-30 1979-05-30 Fire resistant cable
BR8003364A BR8003364A (en) 1979-05-30 1980-05-29 FIRE PROOF CABLE

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7918768A GB2050041B (en) 1979-05-30 1979-05-30 Fire resistant cable

Publications (2)

Publication Number Publication Date
GB2050041A true GB2050041A (en) 1980-12-31
GB2050041B GB2050041B (en) 1983-02-02

Family

ID=10505526

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7918768A Expired GB2050041B (en) 1979-05-30 1979-05-30 Fire resistant cable

Country Status (2)

Country Link
BR (1) BR8003364A (en)
GB (1) GB2050041B (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0100829A3 (en) * 1982-08-06 1984-04-18 Aeg - Telefunken Kabelwerke Ag, Rheydt Halogen-free, fire-resisting cable continuing to function for a certain period in case of fire
US4500748A (en) * 1982-05-24 1985-02-19 Eaton Corporation Flame retardent electrical cable
US4547626A (en) * 1983-08-25 1985-10-15 International Standard Electric Corporation Fire and oil resistant cable
US4605818A (en) * 1984-06-29 1986-08-12 At&T Technologies, Inc. Flame-resistant plenum cable and methods of making
US4659871A (en) * 1982-10-01 1987-04-21 Raychem Limited Cable with flame retarded cladding
WO1992019903A1 (en) * 1991-05-06 1992-11-12 Viking Mjøndalen A.S Multilayer fire protective coating
EP0628972A3 (en) * 1993-06-11 1995-02-22 Bicc Plc Electric cables.
WO1995020227A1 (en) * 1994-01-19 1995-07-27 Huber & Suhner Ag Kabel-, Kautschuk-, Kunststoff-Werke Fire-proof cable
GB2327529A (en) * 1997-07-08 1999-01-27 City Electrical Factors Ltd Fire-resistant electric cable
DE10051962A1 (en) * 2000-10-20 2002-05-02 Alcatel Sa Insulated electrical conductor with functional integrity in the event of a fire
DE10203900A1 (en) * 2002-01-31 2003-08-14 Nexans Electrical line
US6787694B1 (en) 2000-06-01 2004-09-07 Cable Design Technologies, Inc. Twisted pair cable with dual layer insulation having improved transmission characteristics
CN103785333A (en) * 2014-02-20 2014-05-14 刘建国 Energy-saving steam-reforming furnace pipe
CN109637731A (en) * 2018-12-25 2019-04-16 新沂博瑞工业设计有限公司 A kind of flame retardant cable

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6441308B1 (en) 1996-06-07 2002-08-27 Cable Design Technologies, Inc. Cable with dual layer jacket

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4500748A (en) * 1982-05-24 1985-02-19 Eaton Corporation Flame retardent electrical cable
EP0100829A3 (en) * 1982-08-06 1984-04-18 Aeg - Telefunken Kabelwerke Ag, Rheydt Halogen-free, fire-resisting cable continuing to function for a certain period in case of fire
US4659871A (en) * 1982-10-01 1987-04-21 Raychem Limited Cable with flame retarded cladding
US4547626A (en) * 1983-08-25 1985-10-15 International Standard Electric Corporation Fire and oil resistant cable
US4605818A (en) * 1984-06-29 1986-08-12 At&T Technologies, Inc. Flame-resistant plenum cable and methods of making
WO1992019903A1 (en) * 1991-05-06 1992-11-12 Viking Mjøndalen A.S Multilayer fire protective coating
AU676036B2 (en) * 1993-06-11 1997-02-27 Bicc Public Limited Company Electric cables
EP0628972A3 (en) * 1993-06-11 1995-02-22 Bicc Plc Electric cables.
WO1995020227A1 (en) * 1994-01-19 1995-07-27 Huber & Suhner Ag Kabel-, Kautschuk-, Kunststoff-Werke Fire-proof cable
GB2327529A (en) * 1997-07-08 1999-01-27 City Electrical Factors Ltd Fire-resistant electric cable
GB2327529B (en) * 1997-07-08 2001-07-04 City Electrical Factors Ltd Electrical cable
US6787694B1 (en) 2000-06-01 2004-09-07 Cable Design Technologies, Inc. Twisted pair cable with dual layer insulation having improved transmission characteristics
DE10051962A1 (en) * 2000-10-20 2002-05-02 Alcatel Sa Insulated electrical conductor with functional integrity in the event of a fire
DE10203900A1 (en) * 2002-01-31 2003-08-14 Nexans Electrical line
US6720498B2 (en) 2002-01-31 2004-04-13 Nexans Electrical line
CN103785333A (en) * 2014-02-20 2014-05-14 刘建国 Energy-saving steam-reforming furnace pipe
CN109637731A (en) * 2018-12-25 2019-04-16 新沂博瑞工业设计有限公司 A kind of flame retardant cable
CN109637731B (en) * 2018-12-25 2020-08-11 哈尔滨交联电力电缆制造有限公司 a flame retardant cable

Also Published As

Publication number Publication date
BR8003364A (en) 1980-12-30
GB2050041B (en) 1983-02-02

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19960530