Metal sheathed cable with jacketed, cabled conductor subassembly
10847286 ยท 2020-11-24
Assignee
Inventors
- George Anthony Straniero (Cliffwood, NJ, US)
- Paul R. Picard (East Greenwich, RI, US)
- Richard A. Ricci (Somerset, MA, US)
- Peter Lafreniere (Mattapoisett, MA, US)
Cpc classification
H01B7/18
ELECTRICITY
H01B13/22
ELECTRICITY
H01B9/02
ELECTRICITY
International classification
H01B9/02
ELECTRICITY
H01B13/22
ELECTRICITY
H01B7/18
ELECTRICITY
Abstract
A Metal-Clad (MC) cable assembly includes a core having a plurality of power conductors cabled with a subassembly, each of the plurality of power conductors and the subassembly including an electrical conductor, a layer of insulation, and a jacket layer. The MC cable assembly further includes an assembly jacket layer disposed over the subassembly, and a metal sheath disposed over the core. In one approach, the subassembly is a cabled set of conductors (e.g., twisted pair) operating as class 2 or class 3 circuit conductors in accordance with Article 725 of the National Electrical Code. In another approach, the MC cable assembly includes a protective layer disposed around the jacket layer of one or more of the plurality of power conductors and the subassembly. In yet another approach, a bonding/grounding conductor is cabled with the plurality of power conductors and the subassembly.
Claims
1. A metal clad cable assembly, comprising: a core including a plurality of power conductors and a subassembly, wherein each of the plurality of power conductors and the subassembly includes an electrical conductor, a layer of insulation disposed over the electrical conductor, and a jacket layer disposed directly over the layer of insulation, and wherein the layer of insulation and the jacket layer are different materials; an assembly jacket layer between the subassembly and the plurality of power conductors, wherein the jacket layer of at least one conductor of the subassembly is provided directly adjacent the assembly jacket layer, and wherein the jacket layer of at least one of the plurality of power conductors is provided directly adjacent the assembly jacket layer; and a metal sheath disposed over the core.
2. The metal clad cable assembly of claim 1, wherein each electrical conductor of the subassembly has a size between 24 American Wire Gauge (AWG) and 6 AWG, and wherein each electrical conductor of the plurality of power conductors has a size between 18 AWG and 2000 KCM.
3. The metal clad cable assembly of claim 1, further comprising a bonding/grounding conductor positioned directly adjacent at least one of the plurality of power conductors.
4. The metal clad cable of claim 1, further comprising a core jacket layer disposed around the core.
5. A cable assembly, comprising: a plurality of power conductors adjacent a set of conductors, wherein each of the plurality of power conductors and the set of conductors includes an electrical conductor, a layer of insulation disposed over the electrical conductor, and a jacket layer disposed directly atop the layer of insulation, wherein the layer of insulation and the jacket layer are different materials; an assembly jacket layer between the set of conductors and one or more of the plurality of power conductors, wherein the jacket layer of at least one conductor of the set of conductors is provided directly adjacent the assembly jacket layer, and wherein the jacket layer of at least one power conductor of the plurality of power conductors is provided directly adjacent the assembly jacket layer; and a metal sheath disposed over the plurality of power conductors and the set of conductors.
6. The cable assembly of claim 5, wherein each of the set of conductors is configured to conduct a voltage between zero (0) and approximately 300 Volts.
7. The cable assembly of claim 5, further comprising a layer of tape disposed around the plurality of power conductors.
8. The cable assembly of claim 5, further comprising a bonding/grounding conductor adjacent the plurality of power conductors.
9. The cable assembly of claim 5, wherein the plurality of power conductors and the set of conductors are cabled together.
10. The cable assembly of claim 5, wherein the set of conductors is cabled in a left-hand or right-hand lay.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings illustrate exemplary approaches of the disclosed metal clad cable assembly so far devised for the practical application of the principles thereof, and in which:
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
DESCRIPTION OF EMBODIMENTS
(17) The present disclosure will now proceed with reference to the accompanying drawings, in which various approaches are shown. It will be appreciated, however, that the disclosed MC cable assembly may be embodied in many different forms and should not be construed as limited to the approaches set forth herein. Rather, these approaches are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. In the drawings, like numbers refer to like elements throughout.
(18) As used herein, an element or operation recited in the singular and proceeded with the word a or an should be understood as not excluding plural elements or operations, unless such exclusion is explicitly recited. Furthermore, references to one approach of the present disclosure are not intended to be interpreted as excluding the existence of additional approaches that also incorporate the recited features.
(19) As stated above, exemplary approaches provided herein are directed to a Metal-Clad cable assembly. In an exemplary approach, a Metal-Clad (MC) cable assembly includes a core having a plurality of power conductors cabled with a subassembly, each of the plurality of power conductors and the subassembly including an electrical conductor, a layer of insulation, and a jacket layer. The MC cable assembly further includes an assembly jacket layer disposed over the subassembly, and a metal sheath disposed over the core. In one approach, the subassembly is a cabled set of conductors (e.g., twisted pair) operating as class 2 or class 3 circuit conductors, as defined by Article 725 of the NEC. In another approach, each conductor of the core includes a polymeric protective layer disposed around the jacket layer along the length of each of the electrical conductors. In yet another approach, a bonding/grounding conductor is cabled with the plurality of power conductors and the subassembly. These approaches enable Class 2 or 3 low-voltage wiring to be included with power conductors within the metal sheath of an AC or MC cable to add mechanical protection, simplify installation and reduce overall cost.
(20) Referring now to the side view of
(21) The first and second conductors 6A-B of subassembly 2 may each be, for example, 16 American Wire Gauge (AWG) solid conductors, while plurality of conductors 13A-C may each be, for example, 12 AWG solid and/or stranded electrical conductors. In some approaches, the plurality of power conductors 13A-C includes first, second and third power conductors (e.g., 120V or 277V). In an exemplary approach, each of the conductors 6A-B can have a size between 24 AWG and 6 AWG such that conductors 6A-B are configured to conduct a voltage between zero (0) and approximately 300 Volts. In some approaches, each of the plurality of power conductors 13A-C can have a size between 18 AWG and 2000 KCM.
(22) Metal sheath 10 may be formed as a seamless or welded continuous sheath, and has a generally circular cross section with a thickness of about 0.005 to about 0.060 inches. Alternatively, metal sheath 10 may be formed from flat or shaped metal strip, the edges of which are helically wrapped and interlock to form a series of convolutions along the length of the cable 1. In this manner, metal sheath 10 allows the resulting MC cable assembly 1 to have a desired bend radius sufficient for installation within a building or structure. The sheath 10 may also be formed into shapes other than generally circular such as, for example, rectangles, polygons, ovals and the like. Metal sheath 10 provides a protective metal covering around core 5.
(23) Referring now to the cross-sectional views of
(24) The electrical conductor 12, insulation layer 14 and jacket layer 16 may define an NEC Type thermoplastic fixture wire nylon (TFN), thermoplastic flexible fixture wire nylon (TFFN), thermoplastic high heat resistant nylon (THHN), thermoplastic heat and water resistant nylon (THWN) or THWN-2 insulated conductor. In other approaches the conductors 6A-B and 13A-C may define an NEC Type thermoplastic heat and water resistant (THW), thermoplastic high heat and water resistant (THHW), cross-linked polyethylene high heat-resistant water-resistant (XHHW) or XHHW-2 insulated conductor. In one exemplary approach, the insulation layer 14 is polyvinylchloride (PVC) and has a thickness of approximately 15-125 mil. In one approach, jacket layer 16 is nylon and has a thickness of approximately 4-9 mil.
(25) Subassembly 2 is disposed within assembly jacket layer 11, which extends along the length of the subassembly 2 and is located within metal sheath 10 in an area adjacent each power conductor 13A-C. In exemplary approaches, assembly jacket layer 11 is PVC and has a thickness in the range of 5-80 mils. In one non-limiting exemplary approach, assembly jacket layer 11 has a thickness of approximately 15-30 mils. However, it will be appreciated that the thickness of assembly jacket layer 11 can vary depending on the diameter of the core it surrounds. For example, larger diameter conductors generally require a thicker jacket layer. As further shown, an assembly tape 15 may be disposed around the cabled core 5.
(26) As stated above, the subassembly 2 may be cabled, in a right or left handed lay, with the plurality of power conductors 13A-C to form core 5. Alternatively, the subassembly and the plurality of power conductors 13A-C may extend longitudinally along the metal sheath 10 such that the longitudinal axis of each conductor runs parallel to a longitudinal axis of metal sheath 10.
(27) Although not shown, it will be appreciated that MC cable assembly 1 may include one or more filler members within metal sheath 10. In one approach, a longitudinally oriented filler member is disposed within metal sheath 10 adjacent to subassembly 2 and/or one or more of the plurality of power conductors 13A-C to press subassembly 2 and power conductors 13A-C radially outward into contact with the inside surface of metal sheath 10. The filler member can be made from any of a variety of fiber or polymer materials. Furthermore, the filler member can be used with MC Cable assemblies having any number of insulated conductor assemblies.
(28) Referring now to the cross-sectional view of
(29) Similar to above, conductors 6A-B and 13A-C shown in
(30) Referring now to
(31) Similar to above, conductors 6A-B and 13A-C shown in
(32) Referring now to the cross-sectional view of
(33) The communication/data cables 21A-D may be cabled within assembly jacket 11, in a right or left hand lay, and the subassembly 2 may then be cabled (again, with a right or left hand lay) with the plurality of power conductors 13A-C to form core 5. Alternatively, communication/data cables 21A-D may extend longitudinally along the metal sheath 10 such that the longitudinal axis of each communication/data cable runs parallel to a longitudinal axis of metal sheath 10. Although the illustrated embodiment shows four individual communication/data cables 21A-D, it will be appreciated that any number of communication/data cables can be provided to form subassembly 2.
(34) Referring now to the cross-sectional views of
(35) The conductors 6A-B can be cabled together and enclosed in an assembly jacket layer 11 to form a subassembly 2 as previously described in relation to
(36) The MC cable assembly 400 of
(37) In some approaches, the polymeric protective layer 18 has a thickness between 2-15 mils and may be disposed over the jacket layer 16 and more particularly, may be extruded over the jacket layer. Although the polymeric protective layer 18 has been disclosed as being polypropylene, in some approaches it can be made from other materials such as, but not limited to, polyethylene, polyester, etc. The polymeric protective layer 18 can provide mechanical strength to resist buckling, crushing and scuffing of the core 5.
(38) In some approaches, the polymeric protective layer 18 may be a foamed polymeric material that includes air pockets filled with gasses, some or all of which may be inert. The polymeric protective layer 18 may provide proper positioning and tensioning of the bonding/grounding conductor 20. It may also be pliable to provide a conforming surface to that of the inside of the metal sheath or the adjacently positioned conductor assemblies.
(39) Metal sheath 10 may be formed as a seamless or welded continuous sheath, and has a generally circular cross section with a thickness of about 0.005 to about 0.060 inches. The sheath 10 may also be formed into shapes other than generally circular such as, for example, rectangles, polygons, ovals and the like. Metal sheath 10 provides a protective metal covering around core 5 and the bonding/grounding conductor 20.
(40) Although not shown, it will be appreciated that MC cable assembly 400 may include one or more filler members (not shown) within metal sheath 10. In one approach, a longitudinally oriented filler member is disposed within metal sheath 10 adjacent to subassembly 2 and/or one or more of the plurality of power conductors 13A-C to press subassembly 2, power conductors 13A-C and/or bonding/grounding conductor 20 radially outward into contact with the inside surface of metal sheath 10. The filler member can be made from any of a variety of fiber or polymer materials. Furthermore, the filler member can be used with MC Cable assemblies having any number of insulated conductor assemblies.
(41) Referring now to the cross-sectional view of
(42) Referring now to
(43) In this embodiment, conductors 6A-B and 13A-C can each include a stranded or solid electrical conductor 12 having a concentric insulation layer(s) 14, and a jacket layer 16 disposed on the insulation layer 14. In this approach, no polymeric protective layer is present over jacket layer 16 along any of conductors 6A-B and 13A-C, as the assembly tape 15 functions in place of the protective polypropylene layer.
(44) In this embodiment, the conductors 6A-B of MC cable assembly 500 may be cabled together and covered with assembly jacket layer 11 to form subassembly 2. Subassembly 2 may be cabled together, in a right or left hand lay, with the plurality of power conductors 13A-C, and the resulting core 5 may be covered by the assembly tape 15. The bonding/grounding conductor 20 may be cabled with the core 5, or it may be laid parallel to the core 5 within the metal sheath 10.
(45)
(46) As shown in the approaches of
(47) As shown in
(48)
(49) In one non-limiting exemplary approach, about nineteen (19) crests and troughs may be provided per linear foot of bonding/grounding conductor 20. This number is, of course, not limiting and is provided merely for purposes of example. In addition, the peak amplitude A may be selected so that when the cable is fully assembled, the bonding/grounding conductor 20 has an outer dimension (i.e., two times the peak amplitude A) that is about equal to or slightly larger (e.g., 0.005 inches) than the outer diameter of the insulated conductors. In other approaches, the peak amplitude A may be selected so that when the cable is fully assembled, the bonding/grounding conductor 20 has an outer dimension (i.e., two times the peak amplitude A) that is slightly smaller than the outer diameter of subassembly 2 and plurality of power conductors 13A-C.
(50) It will be appreciated that the bonding/grounding conductor 20 can be subject to tension forces during the cabling process, and thus the number of crests and troughs per foot may decrease as the bonding/grounding conductor stretches under such tension. The bonding/grounding conductor 20 may, therefore, be manufactured so that the peak amplitude A of the crests 24 and troughs 26 in the non-tensioned state is slightly greater than the peak amplitude A of the crests 24 and troughs 26 in the tensioned state (i.e., the cabled state).
(51)
(52) It will be appreciated that although sinusoidal and wave geometries have been illustrated, the bonding/grounding conductor 20 can be provided in any of a variety of other geometries to provide the desired undulating arrangement. Examples of such alternative geometries include saw-tooth wave patterns, square wave patterns, spike wave patterns, and the like.
(53) It will be appreciated that the bonding/grounding conductor 20 may have the disclosed undulations (alternating crests and troughs) applied as part of an in-line process of forming an MC cable. Alternatively, the undulations can be imparted to the bonding/grounding conductor 20 in a separate off-line process and then brought pre-formed to the cabling/twisting process used to form the MC cable.
(54) The bonding/grounding conductor 20 may be made from any of a variety of materials, including aluminum, copper, copper clad aluminum, tinned copper and the like. In one non-limiting exemplary approach, the bonding/grounding conductor 20 is aluminum.
(55) Referring now to
(56) Referring now to
(57) As will be appreciated, the various approaches described herein for using the cabled subassembly as class 2 or 3 circuit conductors that are covered by a PVC jacket within a metal clad cable containing power conductors provide a variety of advantages/improvements including, but not limited to, reducing cable installation time and cost, reducing materials (e.g., additional fittings for class 2 or 3 cables), and providing mechanical protection for all conductors within the cable.
(58) While the present disclosure has been described with reference to certain approaches, numerous modifications, alterations and changes to the described approaches are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claims. Accordingly, it is intended that the present disclosure not be limited to the described approaches, but that it has the full scope defined by the language of the following claims, and equivalents thereof. While the disclosure has been described with reference to certain approaches, numerous modifications, alterations and changes to the described approaches are possible without departing from the spirit and scope of the disclosure, as defined in the appended claims. Accordingly, it is intended that the present disclosure not be limited to the described approaches, but that it has the full scope defined by the language of the following claims, and equivalents thereof.