CA1118855A - Electric cables presenting low hazard under fire conditions - Google Patents
Electric cables presenting low hazard under fire conditionsInfo
- Publication number
- CA1118855A CA1118855A CA000295038A CA295038A CA1118855A CA 1118855 A CA1118855 A CA 1118855A CA 000295038 A CA000295038 A CA 000295038A CA 295038 A CA295038 A CA 295038A CA 1118855 A CA1118855 A CA 1118855A
- Authority
- CA
- Canada
- Prior art keywords
- electric cable
- bedding
- sheath
- heat
- low
- 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.)
- Expired
Links
- 239000000463 material Substances 0.000 claims abstract description 19
- 239000000203 mixture Substances 0.000 claims abstract description 13
- 239000004020 conductor Substances 0.000 claims abstract description 12
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 10
- 239000003963 antioxidant agent Substances 0.000 claims abstract description 9
- 239000004014 plasticizer Substances 0.000 claims abstract description 9
- 150000001336 alkenes Chemical class 0.000 claims abstract description 8
- 229920000642 polymer Polymers 0.000 claims abstract description 8
- 229920001577 copolymer Polymers 0.000 claims abstract description 7
- 239000012764 mineral filler Substances 0.000 claims abstract description 7
- 239000000779 smoke Substances 0.000 claims abstract description 6
- 229920001519 homopolymer Polymers 0.000 claims abstract description 5
- 230000003078 antioxidant effect Effects 0.000 claims abstract description 4
- 238000009413 insulation Methods 0.000 claims description 11
- 239000004642 Polyimide Substances 0.000 claims description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 6
- 239000000945 filler Substances 0.000 claims description 6
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims description 6
- 229920001721 polyimide Polymers 0.000 claims description 6
- 229920002367 Polyisobutene Polymers 0.000 claims description 5
- 239000010445 mica Substances 0.000 claims description 5
- 229910052618 mica group Inorganic materials 0.000 claims description 5
- 229920002379 silicone rubber Polymers 0.000 claims description 5
- 239000004945 silicone rubber Substances 0.000 claims description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 4
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 claims description 4
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 4
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 claims description 3
- 229920002943 EPDM rubber Polymers 0.000 claims description 3
- 239000003063 flame retardant Substances 0.000 claims description 3
- 229910052736 halogen Inorganic materials 0.000 claims description 3
- 150000002367 halogens Chemical class 0.000 claims description 3
- 239000004615 ingredient Substances 0.000 claims description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000011707 mineral Substances 0.000 claims description 3
- 239000001993 wax Substances 0.000 claims description 3
- 235000021355 Stearic acid Nutrition 0.000 claims description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 2
- 229920003020 cross-linked polyethylene Polymers 0.000 claims description 2
- 239000004703 cross-linked polyethylene Substances 0.000 claims description 2
- 239000011888 foil Substances 0.000 claims description 2
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 claims description 2
- 239000012188 paraffin wax Substances 0.000 claims description 2
- 239000004033 plastic Substances 0.000 claims description 2
- 229920003023 plastic Polymers 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 239000011347 resin Substances 0.000 claims description 2
- 239000008117 stearic acid Substances 0.000 claims description 2
- 150000004684 trihydrates Chemical class 0.000 claims description 2
- 239000010690 paraffinic oil Substances 0.000 claims 1
- 150000001875 compounds Chemical class 0.000 description 17
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 7
- 229910052802 copper Inorganic materials 0.000 description 7
- 239000010949 copper Substances 0.000 description 7
- 239000005038 ethylene vinyl acetate Substances 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- 239000006057 Non-nutritive feed additive Substances 0.000 description 3
- 229920001971 elastomer Polymers 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000005060 rubber Substances 0.000 description 3
- 239000004677 Nylon Substances 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229920001778 nylon Polymers 0.000 description 2
- 229920003223 poly(pyromellitimide-1,4-diphenyl ether) Polymers 0.000 description 2
- 101100389815 Caenorhabditis elegans eva-1 gene Proteins 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229920003620 Grilon® Polymers 0.000 description 1
- 241001272567 Hominoidea Species 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- DQXBYHZEEUGOBF-UHFFFAOYSA-N but-3-enoic acid;ethene Chemical compound C=C.OC(=O)CC=C DQXBYHZEEUGOBF-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- YNWDKZIIWCEDEE-UHFFFAOYSA-N pantoprazole sodium Chemical compound [Na+].COC1=CC=NC(CS(=O)C=2[N-]C3=CC=C(OC(F)F)C=C3N=2)=C1OC YNWDKZIIWCEDEE-UHFFFAOYSA-N 0.000 description 1
- 230000036314 physical performance Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 229920000260 silastic Polymers 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229920001897 terpolymer Polymers 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
Classifications
-
- 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
-
- 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
- H01B7/02—Disposition of insulation
- H01B7/0208—Cables with several layers of insulating material
Abstract
ABSTRACT
An electric cable has at least one polymeric-insulated conductor which is surrounded by a bedding layer made from a composition comprising a curable alkene homopolymer or copolymer, at least 55% of inert mineral filler, a low-smoke plasticiser, a curing agent for the polymer, and an antioxidant, which is enclosed in a sheath of low-flammability material.
A heat-barrier is preferably interposed between the bedding and the sheath.
An electric cable has at least one polymeric-insulated conductor which is surrounded by a bedding layer made from a composition comprising a curable alkene homopolymer or copolymer, at least 55% of inert mineral filler, a low-smoke plasticiser, a curing agent for the polymer, and an antioxidant, which is enclosed in a sheath of low-flammability material.
A heat-barrier is preferably interposed between the bedding and the sheath.
Description
8~55 This invention rela~es to electric cables and more particularly to cables with polymeric insul.ation, sheathing or other components that present a low hazard under fire conditions. Cables that present no significant primary fire hazard, in the sense that the insulation cannot be ignited by the effect of an electrical fault in a properly protected circui-t, are now readily available. There is however a risk that polymeric materials will burn if pre-heated -to a high temperature by an external source, such as an external fire, 10 with the disadv~ntages that: (i) in certain circumstances fire may be transmitted along ca~le runs to other parts of a building; (ii) dense smoke may be generated; and (iii~ since P~C and/or other halogen-containing materials are commonly present toxic and corrosive fumes ~such as hydrogen chloride gas and/or hydrochloric acid droplets) may be produced.
In accordance with the present invention, an electric cable comprises at least one conductor with insulation of polymeric material, a bedding layer surrounding the insulated conductor and made from a composition comprising a curable 20 alkene homo-polymer or copolymer, at least 55% of inert mineral filler, a low smoke plasticiser, a curing agent for the polymer, and an antioxidant, and an enclosing sheath of low flammability material. Preferably all the components are free of halogen-containing materials or at Least substantially so.
I~ there is more than one conductor one (or exceptionally more than one but not all) of them may be bare.
If the electrical and physical performance requirements of the cable allow it the insulation ls preferably also of curable, mineral-filled, plasticised alkene homopolymer 30 or copolymer composition, but the proportion of filler that is appropriate will be lower than for the bedding. Preferably the weight of filler is not in any instance more than 55% of the whole composition of the insulation.
The beclding cornposition will commonly include up to 80~ ot the filler ancl may include even more. A preferred filler is hydrated alumina o suitable particle size, used alone or mixed with calcium carbonate and/or china clay; a proportion of pigment can be included especially in the insulation where it can be used for colour coding. Preferred pol~ners fox the bedding are the curable ethylene-propylene copolymer rubbers (EPR) and ethylene-propylene-diene 10 terpolymers (EPDM). Preferred plasticisers are polyisobutylene and paraffinic resins, oils or waxes whi~h may advantageously be used together. A preferred range of compositions comprises, in parts by weight:
Polyrner: curable alkene polymer 15-35 Filler: alumina trihydrate with or without calcium carbonata and/or china clay 55-80 Plasticiser(s): polyisobutylene and/or paraffin wax 7-20 Processing aid: stearic acid and/or inorganic stearate up to 5 20 Curing agents and antioxidants:up to 5 The sheath is preferably of suitable polymeric material, and may be of the same composition as the bedding, but materials of higher oxygen index are preerred: ethylene-vinyl acetate copolyrners ~EVA) compounded with at leas-t 5S% of an inert mineral Eillqr and other conventional ingredients, with or without curing agents, are very suitable.
`'~;~'"' ' :
Similar compositions based on mi~tures of EVA with EPR or EPDM, and silicone rubber and flame-retardant grades of cross-linked polyethylene can also be used.
A ma~or improvement in properties can be obtained by interposing a heat-barrier layer of suitable low-~lammability material between the bedding layer and the sheath. Suitable materials include:
(1) flexible metal tape or foil;
In accordance with the present invention, an electric cable comprises at least one conductor with insulation of polymeric material, a bedding layer surrounding the insulated conductor and made from a composition comprising a curable 20 alkene homo-polymer or copolymer, at least 55% of inert mineral filler, a low smoke plasticiser, a curing agent for the polymer, and an antioxidant, and an enclosing sheath of low flammability material. Preferably all the components are free of halogen-containing materials or at Least substantially so.
I~ there is more than one conductor one (or exceptionally more than one but not all) of them may be bare.
If the electrical and physical performance requirements of the cable allow it the insulation ls preferably also of curable, mineral-filled, plasticised alkene homopolymer 30 or copolymer composition, but the proportion of filler that is appropriate will be lower than for the bedding. Preferably the weight of filler is not in any instance more than 55% of the whole composition of the insulation.
The beclding cornposition will commonly include up to 80~ ot the filler ancl may include even more. A preferred filler is hydrated alumina o suitable particle size, used alone or mixed with calcium carbonate and/or china clay; a proportion of pigment can be included especially in the insulation where it can be used for colour coding. Preferred pol~ners fox the bedding are the curable ethylene-propylene copolymer rubbers (EPR) and ethylene-propylene-diene 10 terpolymers (EPDM). Preferred plasticisers are polyisobutylene and paraffinic resins, oils or waxes whi~h may advantageously be used together. A preferred range of compositions comprises, in parts by weight:
Polyrner: curable alkene polymer 15-35 Filler: alumina trihydrate with or without calcium carbonata and/or china clay 55-80 Plasticiser(s): polyisobutylene and/or paraffin wax 7-20 Processing aid: stearic acid and/or inorganic stearate up to 5 20 Curing agents and antioxidants:up to 5 The sheath is preferably of suitable polymeric material, and may be of the same composition as the bedding, but materials of higher oxygen index are preerred: ethylene-vinyl acetate copolyrners ~EVA) compounded with at leas-t 5S% of an inert mineral Eillqr and other conventional ingredients, with or without curing agents, are very suitable.
`'~;~'"' ' :
Similar compositions based on mi~tures of EVA with EPR or EPDM, and silicone rubber and flame-retardant grades of cross-linked polyethylene can also be used.
A ma~or improvement in properties can be obtained by interposing a heat-barrier layer of suitable low-~lammability material between the bedding layer and the sheath. Suitable materials include:
(1) flexible metal tape or foil;
(2) heat-resistant plastics tape, such as polyimides (e.g. those sold under the trademark KAPTON); and
(3) fibre-reinforced bonded mica tape.
The heat-barrier also offers some resistance to emission of volatile materials or smoke from the interior of the cable.
For some types of cable additional components of a conventional kind, for example wire or tape armour and/or a metal sheath, ma~ be included, for example between the parts of a subdivided bedding layer and/or between the parts of a sub-divided sheath.
EXAMPLES
-1. Tinned copper wires each of 0,85 mm diameter are insulated with 0 6 mm radial thickness of a conventional insulating compound (hereinafter called compound EP~ 1) compri.sing:
~thylene~propylene/diene monomer rubber (~PDM) 30-35%
China clay 50%
Paraffinic Plastlcisers 10-15%
Curing agents and antioxidants 5%
(all percentages are by weight of the compound) , .
~ Pairs Or these insulated wires are twisted together with a ¦ right-hand lay o~ about 40 mm~ and seven such t;wlsted pa:crs ¦ laid up together with a le~t-hand lay of about 100 mm, An extruded bedding layer with a nominal radial thickness o~ ] mm encloses the laid up cores, this bedding layer is of the following compound (compound EPR ~J:
EPDM 22%
Hydrated alumina (nominal particle si,~e 6 1 micrometre) 2%
Plasticisers: Polyisobutylene 7.7~J ll Par~ffin wax ~.3%) ~
Processing aid:Stearic ac-Ld 1%
` Convent;onal curing agents and antioxidants l!~o Over this bedding ~s applied a copper tape screen~made of two apes each (nominally) 18 mm wide and 0~1 mm thick, breaking joint with the edges of each tape nominally abutted. A second bedding layer ~.5 mm thick and made of compound EPR 2 is extruded over the screen.
:
A heat barrier is next formed by lapping on tw~
silicone-resin bonded woven-glass reinforced mica tape,s. Eaoh tape is 0.].5 mm thick and ~5 mm wide and applLed with its edges ~,l nominally abutting, khe two tapes breaking joint by half the width of ~he tape~
An outer sheath of a standard nylon sheathing compound ~Grilon ~ype 6J with a radial thickness o~ ~.4 mm completèS t~e cable~ ~hich has an overall diameter o~ 16.5 mm, 2, This is the same as example l except that the n~rlon sheath is replaced by a she~h 1,0 mm thick (increasing the `
overall diameter to about 17.5 mm) of the following compound * ~ r~
. .:, _ 5 w . : ~
.' ~
ss j (Compouncl EVA lJ:
¦ 60~o Ethylenc - I~O~o Vln~l a&etate copolymer2470 Processing aid: Stearic acld 2%
Hydrated alumina ~nominal particle size 0%
. 1 micrometre) 7 Antioxidants (and curing agents if desired) 1~%
3. This cable is the same as examples 1 and 2 llp to and including the first bedding layer Over this is applied a single glass/mica tape of the same kind and size as in the preceding e~amples but applie~ with 20~ overlap. Two copper kapes (also of the same dimensions as in the preceding examplesJ
are applied directly over the glas~s/mica tape~ without a second . .
bedding layer. This cable is completed by an outer sheakh of~a conventional commercially-available flame-retardant silicone rubber j ~ compound ("Silastic(~ 603"J with a radial thickness o~ 1.8 mm ¦ (overall diameter abou~ 16 mm).
The heat-barrier also offers some resistance to emission of volatile materials or smoke from the interior of the cable.
For some types of cable additional components of a conventional kind, for example wire or tape armour and/or a metal sheath, ma~ be included, for example between the parts of a subdivided bedding layer and/or between the parts of a sub-divided sheath.
EXAMPLES
-1. Tinned copper wires each of 0,85 mm diameter are insulated with 0 6 mm radial thickness of a conventional insulating compound (hereinafter called compound EP~ 1) compri.sing:
~thylene~propylene/diene monomer rubber (~PDM) 30-35%
China clay 50%
Paraffinic Plastlcisers 10-15%
Curing agents and antioxidants 5%
(all percentages are by weight of the compound) , .
~ Pairs Or these insulated wires are twisted together with a ¦ right-hand lay o~ about 40 mm~ and seven such t;wlsted pa:crs ¦ laid up together with a le~t-hand lay of about 100 mm, An extruded bedding layer with a nominal radial thickness o~ ] mm encloses the laid up cores, this bedding layer is of the following compound (compound EPR ~J:
EPDM 22%
Hydrated alumina (nominal particle si,~e 6 1 micrometre) 2%
Plasticisers: Polyisobutylene 7.7~J ll Par~ffin wax ~.3%) ~
Processing aid:Stearic ac-Ld 1%
` Convent;onal curing agents and antioxidants l!~o Over this bedding ~s applied a copper tape screen~made of two apes each (nominally) 18 mm wide and 0~1 mm thick, breaking joint with the edges of each tape nominally abutted. A second bedding layer ~.5 mm thick and made of compound EPR 2 is extruded over the screen.
:
A heat barrier is next formed by lapping on tw~
silicone-resin bonded woven-glass reinforced mica tape,s. Eaoh tape is 0.].5 mm thick and ~5 mm wide and applLed with its edges ~,l nominally abutting, khe two tapes breaking joint by half the width of ~he tape~
An outer sheath of a standard nylon sheathing compound ~Grilon ~ype 6J with a radial thickness o~ ~.4 mm completèS t~e cable~ ~hich has an overall diameter o~ 16.5 mm, 2, This is the same as example l except that the n~rlon sheath is replaced by a she~h 1,0 mm thick (increasing the `
overall diameter to about 17.5 mm) of the following compound * ~ r~
. .:, _ 5 w . : ~
.' ~
ss j (Compouncl EVA lJ:
¦ 60~o Ethylenc - I~O~o Vln~l a&etate copolymer2470 Processing aid: Stearic acld 2%
Hydrated alumina ~nominal particle size 0%
. 1 micrometre) 7 Antioxidants (and curing agents if desired) 1~%
3. This cable is the same as examples 1 and 2 llp to and including the first bedding layer Over this is applied a single glass/mica tape of the same kind and size as in the preceding e~amples but applie~ with 20~ overlap. Two copper kapes (also of the same dimensions as in the preceding examplesJ
are applied directly over the glas~s/mica tape~ without a second . .
bedding layer. This cable is completed by an outer sheakh of~a conventional commercially-available flame-retardant silicone rubber j ~ compound ("Silastic(~ 603"J with a radial thickness o~ 1.8 mm ¦ (overall diameter abou~ 16 mm).
4, The conductors, insulation and strandin8 of this : cable are as in example 1. ~ bedding layer of compound EPR 2 is extruded over the laid-up cores to a radial thickness of 5 mm.
Two "Kapton" (krade mark) polyimide tapes~ o.o8 mm thick and nominally 30 mm wide, are lapped on to the bedding la~er, breaking joint. A sheath, 1.8 mm thick, of khe same sil-icone ¦ rubber compound as llsed in example 3, oompletes a cable with an overall diameker of about 23;7 mm.
Two "Kapton" (krade mark) polyimide tapes~ o.o8 mm thick and nominally 30 mm wide, are lapped on to the bedding la~er, breaking joint. A sheath, 1.8 mm thick, of khe same sil-icone ¦ rubber compound as llsed in example 3, oompletes a cable with an overall diameker of about 23;7 mm.
5. The aores of khis cable are screened concentri.c pairs, . wlth a tinned copper inner conductor 1.53 mm in diamete:r, inner dielecbric of compound BPR 1 with a radial thickness of 1 mm, ~¦ outer oonductors made of thirt~-five 0.3 mm diameter tinned I - 6 - :1 ,, ~ . ~ `
, copper wires lapped on wi~h a lay o~ around ~8 mm, outer dielectric also of compound EPR l and also ] mm thick~ and a braided screen made up o~ tinned copper wires each o.]5 mm in diameter, applied 16 spindles 4 ends with a lay o~ 11 mm, two-over-~wo-under-two.
Seven such cores are laid up with one axial core and khe remaining six surrounding it and having a right hand lay of about 230 mm A bedding o~ compound EPR 2 is extruded over ~he laid-up cores and has a radi21 thickness o~ 2 5 mm.
~wo layers o~ the same polyimide tapes as in example 4 are lapped in the same malmer on the bedding, and an outer sheath of the same silicone rubber compound as in examples 3 ~nd 4,~
with a radial thickness of 2 mm, completes a cable with an overall diameter of around 30 mm.
, copper wires lapped on wi~h a lay o~ around ~8 mm, outer dielectric also of compound EPR l and also ] mm thick~ and a braided screen made up o~ tinned copper wires each o.]5 mm in diameter, applied 16 spindles 4 ends with a lay o~ 11 mm, two-over-~wo-under-two.
Seven such cores are laid up with one axial core and khe remaining six surrounding it and having a right hand lay of about 230 mm A bedding o~ compound EPR 2 is extruded over ~he laid-up cores and has a radi21 thickness o~ 2 5 mm.
~wo layers o~ the same polyimide tapes as in example 4 are lapped in the same malmer on the bedding, and an outer sheath of the same silicone rubber compound as in examples 3 ~nd 4,~
with a radial thickness of 2 mm, completes a cable with an overall diameter of around 30 mm.
6. m is is exactly the same as Example 5 except that the polyimide tapes are omitted, slightly reducing the overall diameter.
7. m is is exactly the same as Example 5 except that the silicone rubber sheath is replaced by a sheath of compound jh EVA 1 with a radial thickness of 1~5 mm (overall diameter 29 mm).
8-11. These are exactly the same as Examples 1 - 4 respectlvely except thak the solid wire conductors are replaced by tinned copper strands~ made up o~ seven wires each 0.3 mm in diameterJ the radial thickness o~ t,he insulation is 0.8 mm, and the overall dimensions are correspondingly increased.
12-13. These are the same as Examples 8 and 9 respectively except that the sheath is o~ standard nylon sheathing compound~
0.4 mm thick (as in Example 1).
. . . ..
1 , , '' ~ . ..... ,,.. ~
~- : .
.~ ' 14. Th:is is -the same as Example 2 except that the heat barrier is formed by -two "~apton" (trade mark) polyimide tapes, 0.08 mm thick and nominally 30 mm wide, lapped onto the bedding layer, breaking joint.
The accompanying drawing illustrates the invention and is a diagrammatic cross-section through a cable having a core 1 comprising at least one conductor 2 with insulation 21 of polymeric material, bedding layer 3 of the composition defined, and a sheath 4 of low flammability material.
.
~ ".~
12-13. These are the same as Examples 8 and 9 respectively except that the sheath is o~ standard nylon sheathing compound~
0.4 mm thick (as in Example 1).
. . . ..
1 , , '' ~ . ..... ,,.. ~
~- : .
.~ ' 14. Th:is is -the same as Example 2 except that the heat barrier is formed by -two "~apton" (trade mark) polyimide tapes, 0.08 mm thick and nominally 30 mm wide, lapped onto the bedding layer, breaking joint.
The accompanying drawing illustrates the invention and is a diagrammatic cross-section through a cable having a core 1 comprising at least one conductor 2 with insulation 21 of polymeric material, bedding layer 3 of the composition defined, and a sheath 4 of low flammability material.
.
~ ".~
Claims (17)
1. An electric cable comprising at least one conductor with insulation of polymeric material, a bedding layer surrounding the insulated conductor and made from a composition comprising a curable alkene homopolymer or copolymer, at least 55% of inert mineral filler, a low-smoke plasticiser, a curing agent for the polymer, and an antioxidant, and an enclosing sheath of low-flammability material.
2. An electric cable comprising: at least one conductor with insulation of polymeric material; a bedding layer surrounding the insulated conductor and made from a composition comprising a curable alkene homopolymer or copolymer, at least 55% of inert mineral filler, a low-smoke plasticiser, a curing agent for the polymer, and an antioxidant; a heat-barrier layer of low flammability material around the bedding layer, and an enclosing sheath of low-flammability material.
3. An electric cable as claimed in Claim 2 in which the heat-barrier layer is of flexible metal tape or foil.
4. An electric cable as claimed in Claim 2 in which the heat-barrier layer is of heat-resistant plastics tape.
5. An electric cable as claimed in Claim 2 in which the heat-barrier layer is of polyimide tape.
6. An electric cable as claimed in Claim 2 in which the heat-barrier layer is of fibre-reinforced bonded mica tape.
7. An electric cable as claimed in Claim 1 or Claim 2 preceding claims in which all the components are at least substantially free of halogen-containing materials.
8. An electric cable as claimed in Claim 1 or Claim 2 in which the insulation is of curable, mineral-filled plasticised alkene homopolymer or copolymer composition with not more than 55% of inert mineral filler.
9. An electric cable as claimed in Claim 1 or Claim 2 in which the filler consists of or comprises hydrated alumina.
10. An electric cable as claimed in Claim 1 or Claim 2 in which the said polymer in the bedding is EPR or EPDM.
11. An electric cable as claimed in Claim 1 or Claim 2 in which the plasticiser in the bedding comprises polyisobutylene and/or paraffinic oil and/or wax.
12. An electric cable as claimed in Claim 1 or Claim 2 in which the plasticiser in the bedding layer comprises paraffinic resin.
13. An electric cable as claimed in Claim 1 or Claim 2 in which the bedding comprises, in parts by weight:
curable alkene polymer 15-35 alumina trihydrate with or without calcium carbonate and/or china clay 55-80 polyisobutylene and/or paraffin wax 7-20 stearic acid and/or inorganic stearate up to 5 curing agents and antioxidants: up to 5
curable alkene polymer 15-35 alumina trihydrate with or without calcium carbonate and/or china clay 55-80 polyisobutylene and/or paraffin wax 7-20 stearic acid and/or inorganic stearate up to 5 curing agents and antioxidants: up to 5
14. An electric cable as claimed in Claim 1 or Claim 2 in which the sheath is of the same composition as the bedding.
15. An electric cable as claimed in Claim 1 or Claim 2 in which the sheath is of EVA compounded with at least 55% of an inert mineral filler and other conventional ingredients.
16. An electric cable as claimed in Claim 1 or Claim 2 in which the sheath is based on a mixture of EVA with EPR or EPDM, at least 55% of inert mineral filler, and other conventional ingredients.
17. An electric cable as claimed in Claim 1 or Claim 2 in which the sheath is of a silicone rubber or of a flame-retardant grade of cross-linked polyethylene.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1801/77 | 1977-01-17 | ||
| GB1801/77A GB1583955A (en) | 1977-01-17 | 1977-01-17 | Electric cables |
| GB10267/77 | 1977-03-10 | ||
| GB1026777A GB1583956A (en) | 1977-03-10 | 1977-03-10 | Electric cables |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1118855A true CA1118855A (en) | 1982-02-23 |
Family
ID=26236993
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000295038A Expired CA1118855A (en) | 1977-01-17 | 1978-01-16 | Electric cables presenting low hazard under fire conditions |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5389993A (en) |
| AU (1) | AU3250378A (en) |
| CA (1) | CA1118855A (en) |
| DE (1) | DE2801542A1 (en) |
| FR (1) | FR2377688A1 (en) |
| HK (1) | HK44281A (en) |
| IT (1) | IT1102007B (en) |
| MY (1) | MY8200118A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2915188C2 (en) * | 1979-04-10 | 1983-02-17 | Siemens AG, 1000 Berlin und 8000 München | Plastic-insulated electrical cable with a flame-retardant inner sheath |
| JPS5619804A (en) * | 1979-07-27 | 1981-02-24 | Sumitomo Electric Industries | Flame resisting wire |
| DE3229352C2 (en) * | 1982-08-06 | 1985-01-24 | AEG-Telefunken Kabelwerke AG, Rheydt, 4050 Mönchengladbach | Halogen-free, flame-retardant cable with functional integrity in the event of fire for a certain period of time |
| DE3236395A1 (en) * | 1982-10-01 | 1984-04-05 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | FLAME-RESISTANT OPTICAL MESSAGE CABLE |
| EP0224281B1 (en) * | 1982-10-01 | 1990-12-27 | Raychem Limited | Flame retarded cladding |
| FR2605792B1 (en) * | 1986-10-23 | 1990-03-02 | Cabeltel Cables Electro Teleco | FIREPROOF ELECTRIC CABLE |
| CN107393643A (en) * | 2017-07-26 | 2017-11-24 | 贵州人民电气集团有限公司 | A kind of novel cable |
| CN107498307B (en) * | 2017-10-23 | 2023-05-16 | 浙江盛越电子科技有限公司 | Full-automatic motor assembly machine and assembly method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB572424A (en) * | 1943-09-21 | 1945-10-08 | Duratube & Wire Ltd | Improvements in and relating to the insulation of electrical conductors |
| CH603734A5 (en) * | 1975-04-18 | 1978-08-31 | Daetwyler Ag |
-
1978
- 1978-01-14 DE DE19782801542 patent/DE2801542A1/en not_active Withdrawn
- 1978-01-16 CA CA000295038A patent/CA1118855A/en not_active Expired
- 1978-01-16 FR FR7801117A patent/FR2377688A1/en active Granted
- 1978-01-17 AU AU32503/78A patent/AU3250378A/en active Pending
- 1978-01-17 IT IT47660/78A patent/IT1102007B/en active
- 1978-01-17 JP JP282478A patent/JPS5389993A/en active Pending
-
1981
- 1981-09-03 HK HK442/81A patent/HK44281A/en unknown
-
1982
- 1982-12-30 MY MY118/82A patent/MY8200118A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| HK44281A (en) | 1981-09-11 |
| AU3250378A (en) | 1979-07-26 |
| IT7847660A0 (en) | 1978-01-17 |
| FR2377688A1 (en) | 1978-08-11 |
| JPS5389993A (en) | 1978-08-08 |
| IT1102007B (en) | 1985-10-07 |
| DE2801542A1 (en) | 1978-07-20 |
| MY8200118A (en) | 1982-12-31 |
| FR2377688B1 (en) | 1983-02-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |