Method of manufacturing electrical cable, and resulting product, with reduced required installation pulling force

Patent metadata

Field	Value
Publication number	US-2016012945-A1
Application number	US-201514858872-A
Country	US
Kind code	A1
Filing date	Sep 18, 2015
Priority date	Sep 28, 2004
Publication date	Jan 14, 2016
Grant date	—

Abstract

Disclosed are cable types, including a type THHN cable, the cable types having a reduced surface coefficient of friction, and the method of manufacture thereof, in which the central conductor core and insulating layer are surrounded by a material containing nylon or thermosetting resin. A silicone based pulling lubricant for said cable, or alternatively, erucamide or stearyl erucamide for small cable gauge wire, is incorporated, by alternate methods, with the resin material from which the outer sheath is extruded, and is effective to reduce the required pulling force between the formed cable and a conduit during installation.

First claim

1 - 5 . (canceled)

6 . A method of manufacturing a thermoplastic high heat-resistant nylon-coated (THHN) electrical cable having a reduced installation pulling force through a conduit, the method comprising the steps of:
advancing at least one conductor wire through an extrusion head; supplying nylon polymer to the extrusion head; supplying a silicone based pulling lubricant to the extrusion head; combining the nylon polymer and the silicone based pulling lubricant prior to extrusion to form a cable sheath material; and extruding the cable sheath material from the extrusion head and around the conductor wire so as to form a cable sheath surrounding the conductor wire, the combining step further comprising combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing a concentration of up to about 9% by weight of the silicone based pulling lubricant in the cable sheath and forming an exterior surface for the THHN electrical cable that has a coefficient of friction against an interior surface of a conduit of less than about 0.25.

7 . The method of claim 6 , wherein the step of supplying the silicone based pulling lubricant further comprises supplying the silicone based pulling lubricant that is permeable through the nylon polymer of the formed cable sheath.

8 . The method of claim 7 , wherein the step of supplying the silicone-based pulling lubricant further comprises supplying the silicone based pulling lubricant that is permeable through the nylon polymer of the formed cable sheath and is squeezed therefrom when the THHN electrical cable is pulled through the conduit.

9 . The method of claim 6 , wherein the silicone based pulling lubricant consists essentially of low molecular weight silicone oil.

10 . The method of claim 6 , wherein the silicone based pulling lubricant consists essentially of high molecular weight silicone oil.

11 . The method of claim 6 further comprising a step of extruding a PVC insulation layer around the conductor wire before the step of extruding the cable sheath material.

12 . The method of claim 6 , wherein the extruding step further comprises causing the nylon polymer and the silicone based pulling lubricant to reach at least about 500° F.

13 . The method of claim 6 , wherein the exterior surface of the THHN electrical cable has a coefficient of friction against the interior surface of the conduit of less than about 0.2.

14 . The method of claim 6 , wherein the exterior surface of the THHN electrical cable has a coefficient of friction against the interior surface of the conduit of between about 0.125 and about 0.2.

15 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of between about 5% and about 9% by weight of the silicone based pulling lubricant in the formed cable sheath.

16 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of between about 7% and about 9% by weight of the silicone based pulling lubricant in the formed cable sheath.

17 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of between about 5% and about 6.5% by weight of the silicone based pulling lubricant in the formed cable sheath.

18 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of about 4% by weight of the silicone based pulling lubricant in the formed cable sheath.

19 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of about 5% by weight of the silicone based pulling lubricant in the formed cable sheath.

20 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of about 6% by weight of the silicone based pulling lubricant in the formed cable sheath.

21 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of about 7% by weight of the silicone based pulling lubricant in the formed cable sheath.

22 . The method of claim 6 , wherein the combining step comprises combining the nylon polymer and the silicone based pulling lubricant in relative amounts providing the concentration of about 8% by weight of the silicone based pulling lubricant in the formed cable sheath.

23 . The method of claim 6 , wherein the nylon polymer is a resin material containing the nylon polymer.

24 . A THHN electrical cable manufactured according to the method of claim 6 .

25 . In a process for manufacturing an electrical power cable of a type comprising a conductor and protective sheath surrounding said conductor, in which the protective sheath has at least an exterior portion formed of a layer of thermosetting resin, the improvement in which a pulling lubricant comprising silicone is introduced with the thermosetting resin during manufacture to provide the electrical power cable, the pulling lubricant in a concentration less than about 9% by weight and provided to either permeate throughout, or migrate through said exterior portion of the protective sheath to be available at an exterior surface of the electrical power cable when pulled through a conduit to reduce a required installation pulling force at the exterior surface of the electrical power cable for installation of the electrical power cable through the conduit, the so-manufactured electrical power cable having a characteristic that an average amount of force required to install said electrical power cable through an arrangement of conduit is less than an average amount of force required to install a cable of a same cable type, shape and size having substantially no lubrication at an exterior surface of the cable of the same cable type, shape and size, through said arrangement of the conduit, the arrangement of the conduit being defined as PVC conduit that is sized to accommodate said electrical power cable and an initial 10 foot straight section of conduit, followed by a first 90° bend having a left-orientation, followed by a second 90° bend having a right orientation, followed by a 30 foot straight section of conduit, followed by a third 90° bend having a right-orientation, followed by a 5 foot straight section of conduit, followed by a fourth 90° bend having a right-orientation, followed by a 10 foot straight section of conduit.

26 . The process of claim 25 , wherein the electrical power cable has a characteristic that a coefficient of friction between the electrical power cable and the conduit is less than a coefficient of friction between a comparative cable, of a same type, shape and size manufactured without the pulling lubricant, and the conduit, wherein each coefficient of friction is determinable using the arrangement of the conduit.

27 . The process of claim 25 , wherein the pulling lubricant consists essentially of a low molecular weight silicone oil.

28 .

Assignees

• Southwire Co Llc

Inventors

• Sasse Philip
• Chambers Terry
• Kummer Randy D
• Armstrong John
• Reece David
• Lam Hai

Classifications

• H01B13/24 Primary

  by extrusion {(extrusion of cables with plastic material in general B29C48/15)} · CPC title

• H01B13/145

  Pretreatment or after-treatment · CPC title

• H01B3/465

  Silicone oils · CPC title

• H01B3/443

  from vinylhalogenides or other halogenoethylenic compounds · CPC title

• H01B3/22

  hydrocarbons · CPC title