GB2125207A - Fire resistant electric cable - Google Patents

Fire resistant electric cable Download PDF

Info

Publication number
GB2125207A
GB2125207A GB08222449A GB8222449A GB2125207A GB 2125207 A GB2125207 A GB 2125207A GB 08222449 A GB08222449 A GB 08222449A GB 8222449 A GB8222449 A GB 8222449A GB 2125207 A GB2125207 A GB 2125207A
Authority
GB
United Kingdom
Prior art keywords
electric cable
cables
cable
glass fibre
fire resistant
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.)
Withdrawn
Application number
GB08222449A
Inventor
Ian Paul Greenway
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.)
Clay Cross Co Ltd
Original Assignee
Clay Cross Co Ltd
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 Clay Cross Co Ltd filed Critical Clay Cross Co Ltd
Priority to GB08222449A priority Critical patent/GB2125207A/en
Publication of GB2125207A publication Critical patent/GB2125207A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/08—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances quartz; glass; glass wool; slag wool; vitreous enamels
    • H01B3/082—Wires with glass or glass wool
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
    • H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/29—Protection against damage caused by extremes of temperature or by flame
    • H01B7/295—Protection against damage caused by extremes of temperature or by flame using material resistant to flame

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Insulated Conductors (AREA)

Abstract

A fire resistant electric cable (1) comprising at least one conductor (2) and a covering (4) of glass fibre material, preferably woven and in tape form. The tape (4) may be helically wound around the or each conductor (2), with an electrically insulating coating (3) provided therebetween. Such a coating (3) may be of polyvinyl chloride, polyethylene or polypropylene and the cable (1) can be provided with an outer sheath (6) of a flame retardant polyvinyl chloride composition. <IMAGE>

Description

SPECIFICATION Fire resistant electric cable This invention relates to an electric cable with fire resistant properties.
A well known type of fire resistant cable is the mineral insulated cable comprising at least one conductor embedded within an inorganic powder compacted into a metal sheath, usually, of copper.
This type of known cable contains no organic material at all and was developed to withstand temperatures up to 8000C for four hours without its function being adversely affected. It is well known, however, that mineral insulated cables require special equipment and expertise for their installation and the formation of terminations with such cables is very time consuming.
It is an object of the invention to provide a fire resistant electric cable which is much easier to install than mineral insulated cables but which meets the major operating requirements of the latter as a wiring cable.
Therefore, and in accordance with the present invention, there is provided an electric cable comprising at least one conductor and a covering of glass fibre material.
Preferably, woven glass fibre material is used in the form of woven glass fibre tape which can be helically wound around the conductor or a bundle thereof, the preferred thickness of the tape being 125 microns or 250 microns, depending upon the overall cross-section of the conductor(s).
The preferred overlap between adjacent turns of the helically wound, woven glass fibre tape is from 40% to 60% and, more preferably, 50%.
In a preferred embodiment of electric cable in accordance with the invention there is provided a multi-core/multi-pair electric cable having two or more electric conductors each insulated with a coating of polyvinyl chloride, polyethylene or polypropylene. Additionally, this preferred embodiment of electric cable may be provided with an outer sheath around the fire resistant, woven glass fibre covering, which can be made of polyvinyl chloride with flame retardant characteristics of its own.
In laboratory tests carried out upon cables in accordance with the invention, it has been found that the cables have been operable after being heated for three hours at a temperature of 9500C, even though a certain amount of damage to them was caused by such treatment.
Also, it has been found that cables in accordance with the invention are mechanically robust and self-supporting and are suitable for either surface mounting or for insulation in conduits. Furthermore, their installation is straightforward and they have been found to continue functioning even though damaged by severe heating.
A preferred embodiment of electric cable in accordance with the invention will now be described by way of example and with reference to the accompanying drawing which is a crosssection of the cable.
Referring to the drawing, a twin electric cable, shown generally at 1, comprises a twisted pair of annealed copper conductors 2 each complying with BS 6360 and being insulated with a layer 3 of polyvinyl chloride complying with BS 6746, Type Tl 1.
A woven glass fibre tape 4, having a thickness of 125 microns and a width of 12.5 mm is helically wound around each insulated conductor core 2. This helically wound tape 4 provides a fire resistant, inner covering whilst a polyvinyl chloride outer sheath 5 is also provided. This outer sheath 5 also has flame retardant properties and complies with BS 6746, Type TM 1.
Various sizes of this type of cable 11, having cross-sectional areas of 0.50 mm2 to 4.00 mm2, were manufactured and certain lengths thereof were subjected to the following fire resistant tests.
(a) Testing to IEC 331 - a gas flame at a temperature of 9500C was applied to the cable which was working at a voltage of 250 volts ac.
After three hours, and no electrical breakdown, the voltage was switched off and the gas flame removed. After a subsequent 24 hours, the 250 volts were reapplied to the cable which suffered no electrical failure.
(b) The polyvinyl chloride sheath 5 has also been found to meet the requirements of BS 4066 and IEC 332 relating to "Flame Retardant Characteristics of Electric Cables." (c) Another fire resistant test is defined in CEGB specification 000004 which requires the cable to be subjected to a gas flame at a temperature of 1 0000C and to continue to operate for a minimum of 20 minutes. Application of this test to cables in accordance with the invention showed that after three hours at this temperature, the cables were still functioning satisfactorily. It is to be noted that a standard single wire armoured cable subjected to this test fails within approximately 20 seconds.
Thus, it will be appreciated that cables in accordance with the invention provide most suitable alternatives to mineral insulated cables.
Also, it should be appreciated that the gaps shown between the confronting surfaces of the inner covering 4 and the outer sheath 5, in the drawing, are not present in practice, these confronting surfaces being in intimate contact with each other, due to the particular manufacturing processes.
1. A fire resistant electric cable comprising at least one conductor and a covering of glass fibre material.
2. An electric cable according to claim 1, wherein the material is a woven glass fibre material.
3. An electric cable according to claim 2, wherein the woven glass fibre material is in the form of a tape.
4. An electric cable according to claim 3, wherein the tape is helically wound around the conductor.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fire resistant electric cable This invention relates to an electric cable with fire resistant properties. A well known type of fire resistant cable is the mineral insulated cable comprising at least one conductor embedded within an inorganic powder compacted into a metal sheath, usually, of copper. This type of known cable contains no organic material at all and was developed to withstand temperatures up to 8000C for four hours without its function being adversely affected. It is well known, however, that mineral insulated cables require special equipment and expertise for their installation and the formation of terminations with such cables is very time consuming. It is an object of the invention to provide a fire resistant electric cable which is much easier to install than mineral insulated cables but which meets the major operating requirements of the latter as a wiring cable. Therefore, and in accordance with the present invention, there is provided an electric cable comprising at least one conductor and a covering of glass fibre material. Preferably, woven glass fibre material is used in the form of woven glass fibre tape which can be helically wound around the conductor or a bundle thereof, the preferred thickness of the tape being 125 microns or 250 microns, depending upon the overall cross-section of the conductor(s). The preferred overlap between adjacent turns of the helically wound, woven glass fibre tape is from 40% to 60% and, more preferably, 50%. In a preferred embodiment of electric cable in accordance with the invention there is provided a multi-core/multi-pair electric cable having two or more electric conductors each insulated with a coating of polyvinyl chloride, polyethylene or polypropylene. Additionally, this preferred embodiment of electric cable may be provided with an outer sheath around the fire resistant, woven glass fibre covering, which can be made of polyvinyl chloride with flame retardant characteristics of its own. In laboratory tests carried out upon cables in accordance with the invention, it has been found that the cables have been operable after being heated for three hours at a temperature of 9500C, even though a certain amount of damage to them was caused by such treatment. Also, it has been found that cables in accordance with the invention are mechanically robust and self-supporting and are suitable for either surface mounting or for insulation in conduits. Furthermore, their installation is straightforward and they have been found to continue functioning even though damaged by severe heating. A preferred embodiment of electric cable in accordance with the invention will now be described by way of example and with reference to the accompanying drawing which is a crosssection of the cable. Referring to the drawing, a twin electric cable, shown generally at 1, comprises a twisted pair of annealed copper conductors 2 each complying with BS 6360 and being insulated with a layer 3 of polyvinyl chloride complying with BS 6746, Type Tl 1. A woven glass fibre tape 4, having a thickness of 125 microns and a width of 12.5 mm is helically wound around each insulated conductor core 2. This helically wound tape 4 provides a fire resistant, inner covering whilst a polyvinyl chloride outer sheath 5 is also provided. This outer sheath 5 also has flame retardant properties and complies with BS 6746, Type TM 1. Various sizes of this type of cable 11, having cross-sectional areas of 0.50 mm2 to 4.00 mm2, were manufactured and certain lengths thereof were subjected to the following fire resistant tests. (a) Testing to IEC 331 - a gas flame at a temperature of 9500C was applied to the cable which was working at a voltage of 250 volts ac. After three hours, and no electrical breakdown, the voltage was switched off and the gas flame removed. After a subsequent 24 hours, the 250 volts were reapplied to the cable which suffered no electrical failure. (b) The polyvinyl chloride sheath 5 has also been found to meet the requirements of BS 4066 and IEC 332 relating to "Flame Retardant Characteristics of Electric Cables." (c) Another fire resistant test is defined in CEGB specification 000004 which requires the cable to be subjected to a gas flame at a temperature of 1 0000C and to continue to operate for a minimum of 20 minutes. Application of this test to cables in accordance with the invention showed that after three hours at this temperature, the cables were still functioning satisfactorily. It is to be noted that a standard single wire armoured cable subjected to this test fails within approximately 20 seconds. Thus, it will be appreciated that cables in accordance with the invention provide most suitable alternatives to mineral insulated cables. Also, it should be appreciated that the gaps shown between the confronting surfaces of the inner covering 4 and the outer sheath 5, in the drawing, are not present in practice, these confronting surfaces being in intimate contact with each other, due to the particular manufacturing processes. CLAIMS
1. A fire resistant electric cable comprising at least one conductor and a covering of glass fibre material.
2. An electric cable according to claim 1, wherein the material is a woven glass fibre material.
3. An electric cable according to claim 2, wherein the woven glass fibre material is in the form of a tape.
4. An electric cable according to claim 3, wherein the tape is helically wound around the conductor.
5. An electric cable according to claim 4, wherein the tape is 125 microns or 250 microns thick.
6. An electric cable according to claim 3 or 4, wherein the overlap of adjacent turns of the helically wound tape is from 40% to 60%.
7. An electric cable according to any preceding claim, wherein the or each conductor has an electrically insulating coating, with the glass fibre material covering positioned therearound.
8. An electric cable according to claim 7, wherein the electrically insulating coating is of polyvinyl chloride, polyethylene or polypropylene.
9. An electric cable according to any preceding claim including an outer sheath.
10. An electric cable according to claim 9, wherein the outer sheath is of a flame retardant polyvinyl chloride composition.
11. An electric cable according to any preceding claim which is a multi-core/multi-pair electric cable.
12. An electric cable according to claim 11 which is a flat twin electric cable.
1 3. A flat twin electric cable substantially as hereinbefore described with reference to the accompanying drawing.
GB08222449A 1982-08-04 1982-08-04 Fire resistant electric cable Withdrawn GB2125207A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08222449A GB2125207A (en) 1982-08-04 1982-08-04 Fire resistant electric cable

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08222449A GB2125207A (en) 1982-08-04 1982-08-04 Fire resistant electric cable

Publications (1)

Publication Number Publication Date
GB2125207A true GB2125207A (en) 1984-02-29

Family

ID=10532093

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08222449A Withdrawn GB2125207A (en) 1982-08-04 1982-08-04 Fire resistant electric cable

Country Status (1)

Country Link
GB (1) GB2125207A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996025748A1 (en) * 1995-02-15 1996-08-22 Alphagary Corporation Flame retardant and smoke suppressant composite electrical insulation, insulated electrical conductors and jacketed plenum cable formed therefrom
US6492453B1 (en) 1999-09-24 2002-12-10 Alphagary Corporation Low smoke emission, low corrosivity, low toxicity, low heat release, flame retardant, zero halogen polymeric compositions
ES2646723A1 (en) * 2016-06-08 2017-12-15 Grupo General Cable Sistemas, S.L.U. Anti-fire disposal for cables and procedure for the implementation of such provision (Machine-translation by Google Translate, not legally binding)
WO2022073521A1 (en) * 2020-10-10 2022-04-14 天津首瑞智能电气有限公司 Cable
CN118299112A (en) * 2024-04-03 2024-07-05 广东新亚光电缆股份有限公司 NS type fire-resistant cable and manufacturing system thereof

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB536604A (en) * 1940-06-27 1941-05-21 Commercial Secretaries Ltd Improvements in or relating to flexible electric cables
GB612736A (en) * 1946-05-16 1948-11-17 Henleys Telegraph Works Co Ltd An improved insulated electric conductor
GB622093A (en) * 1947-03-13 1949-04-26 British Insulated Callenders Improvements in insulated electric conductors
GB681084A (en) * 1950-08-05 1952-10-15 British Thomson Houston Co Ltd Improvements in and relating to electric cables
GB688185A (en) * 1951-12-07 1953-02-25 Liverpool Electric Cable Compa Improvements in or relating to electric cables
GB984579A (en) * 1961-09-15 1965-02-24 Anaconda Wire & Cable Co Improvements in conductor strands
GB1583954A (en) * 1977-08-12 1981-02-04 Bicc Ltd Electric cables
GB1597125A (en) * 1977-08-24 1981-09-03 Bicc Ltd Radiating cables
GB2074898A (en) * 1980-05-01 1981-11-11 Textured Products Inc Flame resistant insulated electrical wire and cable construction

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB536604A (en) * 1940-06-27 1941-05-21 Commercial Secretaries Ltd Improvements in or relating to flexible electric cables
GB612736A (en) * 1946-05-16 1948-11-17 Henleys Telegraph Works Co Ltd An improved insulated electric conductor
GB622093A (en) * 1947-03-13 1949-04-26 British Insulated Callenders Improvements in insulated electric conductors
GB681084A (en) * 1950-08-05 1952-10-15 British Thomson Houston Co Ltd Improvements in and relating to electric cables
GB688185A (en) * 1951-12-07 1953-02-25 Liverpool Electric Cable Compa Improvements in or relating to electric cables
GB984579A (en) * 1961-09-15 1965-02-24 Anaconda Wire & Cable Co Improvements in conductor strands
GB1583954A (en) * 1977-08-12 1981-02-04 Bicc Ltd Electric cables
GB1597125A (en) * 1977-08-24 1981-09-03 Bicc Ltd Radiating cables
GB2074898A (en) * 1980-05-01 1981-11-11 Textured Products Inc Flame resistant insulated electrical wire and cable construction

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996025748A1 (en) * 1995-02-15 1996-08-22 Alphagary Corporation Flame retardant and smoke suppressant composite electrical insulation, insulated electrical conductors and jacketed plenum cable formed therefrom
US5670748A (en) * 1995-02-15 1997-09-23 Alphagary Corporation Flame retardant and smoke suppressant composite electrical insulation, insulated electrical conductors and jacketed plenum cable formed therefrom
US6492453B1 (en) 1999-09-24 2002-12-10 Alphagary Corporation Low smoke emission, low corrosivity, low toxicity, low heat release, flame retardant, zero halogen polymeric compositions
US7078452B2 (en) 1999-09-24 2006-07-18 Alphagary Corporation Low smoke emission, low corrosivity, low toxicity, low heat release, flame retardant, zero halogen polymeric compositions
ES2646723A1 (en) * 2016-06-08 2017-12-15 Grupo General Cable Sistemas, S.L.U. Anti-fire disposal for cables and procedure for the implementation of such provision (Machine-translation by Google Translate, not legally binding)
WO2022073521A1 (en) * 2020-10-10 2022-04-14 天津首瑞智能电气有限公司 Cable
CN118299112A (en) * 2024-04-03 2024-07-05 广东新亚光电缆股份有限公司 NS type fire-resistant cable and manufacturing system thereof

Similar Documents

Publication Publication Date Title
US4547626A (en) Fire and oil resistant cable
US2454625A (en) Insulated electrical conductor and method of fabricating the same
CN108369841B (en) Fire-resistant cable
US10236098B1 (en) Fireproof cable with ceramified silicone rubber insulating sheath and stainless steel interlocked armor
GB2050041A (en) Fire resistant cable
CN102760526A (en) Ceramic silicon rubber insulation medium-voltage fire-resistant cable with rated voltage of 6-35kV and machining process thereof
KR20000064965A (en) Nonlinear Dielectric / Glass Insulated Electrical Cable and Manufacturing Method
RU47131U1 (en) FIRE RESISTANT ELECTRICAL CABLE
US2090510A (en) Electrical conductor and method of manufacture
GB2125207A (en) Fire resistant electric cable
CN207489561U (en) Clean type low smoke and zero halogen flexible mineral matter insulated cable
KR20170111049A (en) Fire resistant cable
FR2553594B1 (en) CONNECTOR FOR INSULATED ELECTRICAL CABLES
CN211578436U (en) Low-voltage flexible mineral insulated fireproof cable
US2393935A (en) Joint for electric power cables
US3180925A (en) Conductor strand
CA1058715A (en) Fire retardant electric cables
RU58777U1 (en) FIRE RESISTANT CABLE
CN221175830U (en) Fireproof low-voltage power cable
EP4060684A1 (en) Electrical cable
RU203498U1 (en) POWER CABLE SEALED FOR MEDIUM AND HIGH VOLTAGE
CN217086221U (en) Waterproof and fireproof thin steel wire armored power cable
EP0040035A1 (en) Electric cables
CN212161377U (en) Waterproof rat and termite prevention medium-voltage power cable for subway ring network
GB2165690A (en) Electrical cables

Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)