US3745230A

US3745230A - Metal sheathed electrical wire cable

Info

Publication number: US3745230A
Application number: US00217195A
Authority: US
Inventors: W Kelly
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-01-12
Filing date: 1972-01-12
Publication date: 1973-07-10
Anticipated expiration: 1990-07-10

Abstract

A metal sheathed electrical wire cable having a sheath formed of a metal strip. The strip is formed to define a space in which a pair of wires are positioned. The opposite edtes of the strip are joined together and urged downwardly to between the wires to define a substantially fully enclosed raceway for each of the respective wires. The edge portions may comprise flanges facially welded together at a point remote from the wires so as to avoid heat damage to the wire insulation. The sheath may be provided with a longitudinal notch to define a means for facilitating tearing of the sheath to expose desired wire portions.

Description

United States Patent 1191 Kelly 11] 3,745,230 1451 July 10,1973

[ METAL SHEATHED ELECTRICAL WIRE CABLE [76] Inventor: William D. Kelly, 12 Blodgett St.,

Clarendon Hills, Ill. 60514 [22] Filed: Jan. 12, 1972 [21] Appl. No.: 217,195

Related US. Application Data [63] Continuation-impart of Ser. No. 41,007, May 27,

1970, abandoned.

[52] US. Cl. 174/103, 174/113 R, 174/117 R [51] Int. Cl. H01b 7/18 [58] Field of Search 174/103 R, 117 R, 174/72 R, 78, 68 C, 95, 97, 26 R, 27, 105 R,

[56] References Cited UNITED STATES PATENTS 9/1965 Jachimowicz 174/105 R 3/1969 Kelly 174/103 X 10/1968 Kelly 3,422,214 l/1969 Kelly 174/103 1,784,217 12/1930 Berry 174/103 X 1,840,536 l/l932 Shore 174/103 X 2,043,044 6/1936 Knoderer 174/103 X Primary Examiner--Bernard A. Gilheany Assistant ExaminerA. T. Grimley AttorneyAxe1 A. Hofgren et al.

[5 7] ABSTRACT A metal sheathed electrical wire cable having a sheath formed of a metal strip. The strip is formed to define a space in which a pair of wires are positioned. The opposite edtes of the strip are joined together and urged downwardly to between the wires to define a substantially fully enclosed raceway for each of the respective wires. The edge portions may comprise flanges facially welded together at a point remote from the wires so as to avoid heat damage to the wire insulation. The sheath may be provided with a longitudinal notch to define a means for facilitating tearing of the sheath to expose desired wire portions.

21 Claims, 20 Drawing Figures Patented July 10, 1973 2 Sheets-Sheet 2 & B

I METAL SHEATI-IED ELECTRICAL WIRE CABLE CROSS-REFERENCE TO RELATED APPLICATIONS This application comprises a continuation-in-part of my copending application, Ser. No. 41,007, filed May 27, 1970, now abandoned and entitled Metal Sheathed Electrical Wire Cable.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electrical wire cable and in SUMMARY OF THE INVENTION The present invention comprehends an improved method of forming an electrical wire cable wherein the sheath is formed from a flat strip facilitating insertion of the wires into a partially formed wire receiving space. The opposite edges of the strip are brought together and joined as by welding or other suitable positive joining means to define a complete enclosure of the wires. The joint is then brought down to between the wires substantially fully to the opposed portion of the sheath whereby the sheath defines substantially completely enclosing raceways for each of the wires with effectively minimum spacing therebetween for effectively minimum overall size of the cable.

The joint may comprise flanges, formed in the opposite edges of the strip, which are facially juxtaposed to project away from the tubular wire enclosure during the joining operation. Thus, where the joining operation comprises a welding operation, such as a continuous seam welding operation, the heat of the welding operation is prevented from injuring the insulation of the wires by virtue of the substantial spacing of the portions being welded from the wires as well as the projection thereof into the ambient atmosphere. Still further, the joint may be cooled by a suitable fluid coolant, such as air, immediately subsequent to the welding operation to further dissipate thermal energy precluding damage to the wire insulation.

A longitudinal notch may be provided in the sheath portion opposed to the joint for facilitated stripping of the sheath from the wires.

The resultant metal sheathed wire cable provides the highly desirable advantages of a direct path to ground, completely waterproof characteristics permitting installation directly in concrete and the like, high economy of manufacture, and facilitated stripping as for making electrical connections to the wires and for facilitated grounding of the cable.

The joining operation alternatively may comprise the adhesive bonding of the joint flanges. As disclosed, the bonding means may comprise a thermosetting resin, such as an epoxy resin.

The flanges may be provided with grooves for receiving a portion of the bonding medium and facilitating the forming of the desired bond between the flanges. The grooves may extend longitudinally along the strip, and in the illustrated embodiment, are provided in each flange for further improved bonding. The resin may be set by suitable thermal transfer means.

In another form of electrical cable embodying the invention, one or more additional wires may be enclosed in the metal sheath outboard of one of the wires. Thus, one section of the intumed sheath may define a plurality of raceways for receiving a plurality of wires. As will be obvious to those skilled in the art, such a plurality of wires may be sheathed in the section of the cable at each of the opposite sides of the joint if so desired.

BRIEF DESCRIPTION OF THE DRAWING Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. 1 is a perspective view of a sheathed electrical wire cable embodying the invention;

FIG. 2 is an end elevation of a metal strip for use in forming the sheath thereof;

FIG. 3 is an end elevation illustrating a first step in the forming of the sheath;

FIG. 4 is an end elevation illustrating a second step in the forming of the sheath;

FIG. 5 is an end elevation illustratng the placing of the wires within the partially enclosing sheath in a third forming step;

FIG. 6 is an end elevation of the arrangement of the assembly during a fourth forming step wherein the flange edges are joined;

FIG. 7 is an end elevation illustrating a further forming step; I

FIG. 8 is an end elevation of the sheathed cable;

FIG. 9 is a side elevation illustrating a cross-notching of the sheath for controlling a stripping operation of an end portion thereof;

FIG. 10 is a side elevation similar to that of FIG. 9 illustrating the arrangement of the cable as upon initiation of the tearing operation;

FIG. 11 is a view illustrating the grounding of the cable;

FIG. 12 is an end elevation illustrating a first step in a modified form of electrical wire cable embodying the invention;

FIG. 13 is an end elevation illustrating a further step in the forming thereof;

FIG. 14 is an end elevation illustrating a further step in the forming thereof;

FIG. 15 is an end elevation illustrating a further step in the forming thereof;

FIG. 16 is an end elevation illustrating a further step in the forming thereof;

FIG. 17 is an end elevation illustrating a further step in the forming thereof;

FIG. 18 is an end elevation illustrating a further step in the forming thereof;

FIG. 19 is a perspective view of the modified form of sheathed electrical wire cable; and

FIG. 20 is a perspective view of still another modified form of sheathed electrical cable embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the exemplary embodiment of the invention as disclosed in FIGS. 1-1 1 of the drawing, a sheathed electrical wire cable generally designated is shown to include an outer metal sheath 11 defining a pair of

parallel raceways

12 and 13 in which are received respectively

wires

14 and 15 having an outer insulation 16 and 17, respectively. Cable 10 comprises an improved electrical wire cable which is waterproof and, thus, is adapted for installation such as in concrete as well as in normal cable installations.

Sheath 11 is preferably formed of a strip of sheet material 18 having a first mid-portion 19 and

opposite edge portions

20 and 21. The strip defines a longitudinal centerline 22

intermediate edge portions

20 and 21. A semi-perforation, or notch, 23, is provided in lower face 24 of mid-portion 19 to define a tear line in sheath 11 as will be brought out more fully hereinafter.

As seen in FIGS. 3-8, cable 10 is formed by a succession of steps in which strip 18 is caused to define the wire enclosing sheath in a new and improved manner. As shown in FIG. 3,

edge portions

20 and 21 may firstly be turned from the flat plane of the strip to define downwardly extending flanged end portions. The

insulated wires

14 and 15 may be fed into overlying juxtaposition to the upper surface of the strip as seen in FIG. 3. The strip is next formed arcuately at

portions

25 and 26 to bring the

flanged end portions

20 and 21 to a spaced, facially juxtaposed relationship, as shown in FIG. 5. The

insulated wires

14 and 15 are maintained in the desired spaced relationship in the space 27 defined by the partial] wrapped strip. As shown in FIG. 6, the movement of

end portions

20 and 21 is continued until the flanged edge portions are in facial abutment. At this point in the manufacture,

arcuate portions

25 and 26 are substantially semi-cylindrical. The abutting

flanged edge portions

20 and 21 are now permanently joined. As shown herein, the edge portions are joined by means for effecting thermal fusion of the edge portions, such as continuous seam roller electrodes 28 and As shown in FIG. 6,

flanges

20 and 21 project substantially away from space 27 in which

wires

14 and 15 are received whereby thermal energy introduced in effecting the welding is prevented from having a deleterious effect on the insulation of the wires. Not only is the weld point substantially spaced from the wires by this means, but also, the weld is exposed to the ambient atmosphere for facilitated dissipation of heat energy. If desired, suitable blower means 30 may be provided for providing a coolant fluid, such as air, against the welded flanges subsequent to the welding operation, thereby to further remove heat energy and prevent damage to the insulation.

The now fully enclosing, partially formed sheath is further formed to cause individual, substantially full enclosure of the

respective wires

14 and 15 therein, by a movement of the welded

flanges

20 and 21 downwardly toward mid-portion 19 to a final position as shown in FIG. 8 wherein the welded

flanges

20 and 21 extend fully downwardly to the mid-portion 19 on opposite sides of centerline 22. In bringing the joined flange portion to this position, the

arcuate portions

25 and 26 are further extended to define segmentally cylindrical sheath portions extending over 270 about the respective wires whereby each of

raceways

12 and 13 is substantially fully enclosed. By referring respectively to FIGS. 7 and 8, it may be seen that the

arcuate portions

25 and 26 are, in effect, rolled along bottom portion 19 so as to bring

wires

14 and 15 more closely together and cause the opposite extremities of portion 19, as shown in FIG. 7, to become arcuate and become portions of the

cylindrical portions

25 and 26, as shown in FIG. 8.

The spacing of

wires

14 and 15, as shown in FIG. 8, is preselected by the total width of four thicknesses of the original strip 18. The single

weld joining flanges

20 and 21 thusly serves as means for permitting separate enclosure of each of

raceways

12 and 13 upon the further forming of the welded joint, as seen in FIG. 8. As only a single weld is required and the wires may be fed into the space 27 laterally through the partialy formed sheath, as shown in FIG. 5, high rates of forming speed may be employed while yet the configuration of the cable may be accurately controlled. The width of the cable is effectively minimum thereby permitting facilitated bending of the cable both parallel to the plane of the axes of the wires as well as perpendicular thereto.

As seen in FIGS. and 10, when it is desired to remove a portion of the sheath 11, such as for exposing the ends of the wires for making an electrical connection, a transverse notch 31 may be provided about the sheath across the longitudinal notch 23. The end of the sheath at notch 23 may be pried up as shown in FIG. 10, permitting a forceful removal of the portion out wardly of notch 31 by the simple manipulation thereof as with a hand tool, such as a conventional pliers. The notch 31 limits the tearing to define the extent of the uncovered wires.

Sheath 11 may be formed of any suitable material, such as aluminum, galvanized steel, etc. In the illustrated embodiment, where the wires are 12 ga. plastic insulated wires, the sheath may illustratively be formed of 0.012 inch, or thicker, sheet metal. The forming operation may be effected by any conventional method, such as roll forming, to provide high speed manufacture of the cable. The semi-perforation of sheet 18 to define notch 23 may be effected by any suitable notching means.

Cable 10, by virtue of its improved flexibility, may be provided in coil form in conventional market-size coils.

Additional wires may be included in the sheath and separated from each other by forming the sheath downwardly therebetween.

As indicated above, a semi-perforation 23 is provided in lower face 24 of the strip. As shown in the drawing, the semi-perforation may be provided by means of a wheel 32 having an annular projection 33 engaging the lower face 24 of the strip. A corresponding backup roller 34 may be provided to hold the strip against the action of the semi-perforating wheel whereby the annular projection 33 forms a longitudinal groove in the undersurface 24 of the strip. A plurality of such wheels and rollers are positioned longitudinally along the strip so as to further define means for aligning the strip accurately longitudinally the length thereof and thereby facilitating the forming operations. Thus, the annular projection 33a of a second wheel 32a cooperates with a second roller 34a to hold the strip accurately in longitudinally centered relationship in the roll forming operations illustrated therein. Correspondingly

successive wheels

32b, 32c, 32d, 32e and 32f may be utilized in conjunction with corresponding cooperating rollers 34b, 3410 in the steps illustrated in FIGS. 4 and 5, and alone as undersupports of the formed strip in the steps shown in FIGS. 6, 7 and 8 to assist in guiding the formed strip in the various roll forming steps.

Because of the increased accuracy in centering the strip during the forming steps, tolerances in the strip width are not critical. Thus, it is unnecessary to use expensive highly width-controlled strip while yet close control in the overall configuration of the final cable 10 is readily obtained.

The use of the semi-perforation groove 23 further permits a facilitated grounding of the cable as to an entrance wall 35 of an element such as a junction box. Thus, as shown in FIG. 11, the cable may be brought through a suitable opening 36 in wall 35 and the end of the sheath stripped back along line 23 to a transverse score line 31 along the upper face thereof as seen in FIGS. 10 and 11. The end of the sheath, however, is not removed from the cable along the underside thereof thereby maintaining an electrical connection between the partially removed sheath end and the remainder of the sheath. The partially removed sheath end may be laid open and folded back along the transverse line 21 which in the lower portion defines a fold line. The folded back sheath end portion 37 may then be facially juxtaposed to the junction box wall 35 and suitable screw means 38 passed therethrough to make a positive ground connection between the sheath portion 37 and the junction box. Thus,

grooves

23 and 31 further provide for improved facilitated grounding of the sheath in such structures.

Referring now to the embodiment of FIGS. 12-19, a modified form of sheathed electrical wire cable generally designated 110 is shown to include an outer metal sheath 111 receiving a pair of

wires

114, 115 in a pair of parallel spaced

raceways

112, 113, respectively. Cable 110 differs from cable 10 in that the

flange edge portions

120 and 121 are joined by an adhesive bond rather than the fusion weld of cable 10.

Thus, as shown in FIGS. 12-18, the metal strip 118 may firstly be provided with a plurality of longitudinally extending grooves 142 in one face of the

edges

120 and 121 by means of suitable grooving rollers 143 and backup rollers 144, as shown in FIG. 12. The notch 123 may be provided in the lower face 124 of the strip by means of the wheel 132 having a notched projection 133 cooperating with a backup roller 144.

As shown in FIG. 13, the

edge portions

120 and 121 are firstly turned from the flat plane of the strip as by suitable wheels 145 pressing the edge portions about a pair of suitable supports 146. The

edge portions

120 and 121 are then brought upwardly by a pair of rollers 147 engaging the strip and urging it upwardly about roller guides 148, as shown in FIG. 14. Wheels 145 further comprise means for applying a body of thermosetting resin 149 to the upper surfaces 150 of the

flange portions

120 and 121 which may be partially set by suitable heating means, such as infrared lamps 151 when the flanges are brought upwardly to an approximatcly horizontal position. The grooves 142 serve to retain the resin on the flange surfaces 150 to assure proper complete bonding of the flanges to each other in the completed form of the cable.

As shown in FIG. 15, the metal sheath is further formed in the next step by suitable further rollers 152 to bring the

flanges

120 and 121 into facially confronting relationship with the

wires

114 and 115 partially enclosed therein.

As shown in FIG. 16, the flanges may be brought together such as by suitable rollers 153 which may be suitably heated as by suitable heating elements 154 to complete the setting of the thermoset plastic, thereby effectively positively bonding the flanges together to form the desired joint generally designated 155. Joint 155 is then brought down between the two

wires

114 and 115 in a manner similar to that shown in FIGS. 7 and 8 relative to the forming of sheathed cable 10 to form the final sheathed cable as shown in FIG. 19.

In the illustrated embodiment, the adhesive bond is formed by a suitable bonding plastic, and as discussed above, may comprise a thermoset plastic. One example of an excellent thermoset plastic for this purpose comprises an epoxy resin. An excellent example of such an epoxy resin is bisphenol-A-based epichlorohydrin resin. The resin may be made extremely flameretardant by using brominated bisphenol-A therein. As will be obvious to those skilled in the art, other suitable plastic materials or adhesive bonding means may be employed within the scope of the invention.

The sheath 118 may be formed of any suitable material. In the illustrated embodiment, the sheath is formed of a metal, such as aluminum, galvanized steel, etc. Wires 114 and may comprise conventional insulated wires, such as plastic insulated wires. The semiperforation 123 functions similarly as semi-perforation 23 in cable 10 in permitting facilitated stripping of the end of the wire when desired.

As discussed previously, where additional wires are desired in the cable, they may be provided as shown in FIG. 20 by forming the sheath 218 with additional inturned portions 256 to form a cable generally designated 210 having three or more insulated wires therein. Thus, as shown in FIG. 20, a third raceway 257 may be formed outboard of raceway 212 by the provision of the inturned portion 256 for carrying a third insulated wire 258 in addition to the first pair of

wires

214 and 215 disposed on opposite sides of the joint 255. While cable 210 in FIG. 20 illustrates the provision of a threewire cable, as will be obvious to those skilled in the art, any additional number of wires may be provided by the use of additional inturned portions, and such additional wires may be provided on either or both sides of the joint 255 as desired. In each form, the joint 255 effects a substantially full enclosure of all of the wires irrespective of the numbers of inturned portions 256 as the joint effectively completes the forming of single envelopes about the entire plurality of wires. As will also be obvious to those skilled in the art, the joint may comprise the welded joint of cable 10 or the bonded joint of cable 110 as desired within the scope of the invention.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

1 claim:

1. An electrical cable comprising:

a one-piece elongated metal sheath defining a longitudinal centerline in a first wall portion, a pair of raceways at opposite sides of said centerline comprising opposite side portions of said elongated sheath inturned back to adjacent said longitudinal centerline to define tubular spaced second raceway wall portions, and a longitudinally extending joint disposed between said raceways and extending from adjacent said first wall portion outwardly between said raceways comprising the distal edge portion of said sheath returned from said sheath side portions, said distal edge portions being fixedly facially joined; and

insulated electrical wires extending longitudinally in said raceways.

2. The electrical cable of claim 1 wherein said joint comprises a welded joint.

3. The electrical cable of claim 2. wherein said joint comprises a seam welded joint.

4. The electrical cable of claim 1 wherein four substantially equal thicknesses of said sheath are disposed between said raceways.

5. The electrical cable of claim 1 wherein said joint comprises a pair of planar sheath edge portions in facial juxtaposition.

6. The lectrical cable of claim 1 wherein said joint contacts said first wall portion at opposite sides of said centerline.

7. The electrical cable of claim 1 wherein said joint comprises substantially planar edge portions of the sheath and said raceways are defined by substantially cylindrical portions extending over 270 about the wires.

8. The electrical cable of claim 1 wherein said distal edge portions are fixedly facially joined by an adhesive bond.

9. The electrical cable of claim 1 wherein said distal edge portions are fixedly facially joined by a set thermosetting resin bond.

10. The electrical cable of claim 1 wherein said distal edge portions are fixedly facially joined by a set epoxy resin bond.

11. The electrical cable of claim 1 wherein said distal edge portions define a plurality of longitudinal grooves and are fixedly facially joined by bonding means provided in said grooves.

12. The electrical cable of claim 1 wherein said sheath further defines a third raceway outwardly of said second raceway, said centerline being disposed substantially one-third the width of said cable from the side thereof adjacent said first raceway to be disposed between said first and second raceways, and a third insulated wire is disposed coaxially in said third raceway.

13. The electrical cable of claim 1 wherein said sheath further defines a third raceway outwardly of said second raceway, said centerline being disposed substantially one-third the width of said cable from the side thereof adjacent said first raceway to be disposed between said first and second raceways, and a third insulated wire is disposed coaxially in said third raceway, said first wall portion being provided with an outwardly opening longitudinal groove defining a tear line for facilitating stripping of the sheath from the wires to expose selected wire portions, said groove being disposed substantially at said centerline.

14. The electrical cable of claim 1 wherein said sheath is further inturned to define at least one additional raceway.

15. An electrical cable comprising:

an elongated metal sheath defining a longitudinal centerline in a first wall portion, a pair of raceways at opposite sides of said centerline, and a longitudinally extending joint disposed between said raceways and extending from a second wall portion opposite said first wall portion to said first wall portion whereby said raceways define substantially separated raceways; and

insulated electrical wires extending longitudinally in said raceways, said first wall portion being provided with an outwardly opening longitudinal groove defining a tear line for facilitating stripping of the sheath from the wires to expose selected wire portions.

16. An electrical cable comprising:

insulated electrical wires extending longitudinally in said raceways, the end of said sheath being partially stripped and folded back, and screw means being provided in association with the stripped end for grounding the cable.

17. The electrical cable of claim 16 wherein said folded stripped end extends substantially perpendicularly to the longitudinal extent of the cable.

18. An electrical cable comprising:

a one-piece elongated metal strip sheath defining a longitudinal centerline in a first wall portion, a pair of raceways at opposite sides of said centerline comprising opposite side portions of said elongated sheath inturned back to adjacent said longitudinal centerline to define tubular spaced second raceway wall portions, and a longitudinally extending joint disposed between said raceways and extending from adjacent said first wall portion outwardly between said raceways comprising the distal edge portion of said sheath returned from said sheath side portions;

adhesive means bonding said distal edge portions together whereby said edge portions are fixedly facially joined; and

insulated electrical wires extending longitudinally in said raceways.

19. The electrical cable of claim 18 wherein said adhesive means comprises a thermoset plastic.

20. The electrical cable of claim 18 wherein at least one of said side edge portions is provided with a groove extending longitudinally of the strip and receiving a portion of said adhesive means.

21. The electrical cable of claim 18 wherein said side edge portions are provided with a plurality of grooves extending longitudinally of the strip and receiving a portion of said adhesive means.

Claims

1. An electrical cable comprising: a one-piece elongated metal sheath defining a longitudinal centerline in a first wall portion, a pair of raceways at opposite sides of said centerline comprising opposite side portions of said elongated sheath inturned back to adjacent said longitudinal centerline to define tubular spaced second raceway wall portions, and a longitudinally extending joint disposed between said raceways and extending from adjacent said first wall portion outwardly between said raceways comprising the distal edge portion of said sheath returned from said sheath side portions, said distal edge portions being fixedly facially joined; and insulated electrical wires extending longitudinally in said raceways.

2. The electrical cable of claim 1 wherein said joint comprises a welded joint.

3. The electrical cable of claim 2 wherein said joint comprises a seam welded joint.

6. The electrical cable of claim 1 wherein said joint contacts said first wall portion at opposite sides of said centerline.

7. The electrical cable of claim 1 wherein said joint comprises substantially planar edge portions of the sheath and said raceways are defined by substantially cylindrical portions extending over 270* about the wires.

15. An electrical cable comprising: an elongated metal sheath defining a longitudinal centerline in a first wall portion, a pair of raceways at opposite sides of said centerline, and a longitudinally extending joint disposed between said raceways and extending from a second wall portion opposite said first wall portion to said first wall portion whereby said raceways define substantially separated raceways; and insulated electrical wires extending longitudinally in said raceways, said first wall portion being provided with an outwardly opening longitudinal groove defining a tear line for facilitating stripping of the sheath from the wires to expose selected wire portions.

16. An electrical cable comprising: an elongated metal sheath defining a longitudinal centerline in a first wall portion, a pair of raceways at opposite sides of said centerline, and a longitudinally extending joint disposed between said raceways and extending from a second wall portion opposite said first wall portion to said first wall portion whereby said raceways define substantially separated raceways; and insulated electrical wires extending longitudinally in said raceways, the end of said sheath being partially stripped and folded back, and screw means being provided in association with the stripped end for grounding the cable.

18. An electrical cable comprising: a one-piece elongated metal strip sheath defining a longitudinal centerline in a first wall portion, a pair of raceways at opposite sides of said centerline comprising opposite side portions of said elongated sheath inturned back to adjacent said longitudinal centerline to define tubular spaced second raceway wall portions, and a longitudinally extending joint disposed between said raceways and extending from adjacent said first wall portion outwardly between said raceways comprising the distal edge portion of said sheath returned from said sheath side portions; adhesive means bonding said distal edge portions together whereby said edge portions are fixedly facially joined; and insulated electrical wires extending longitudinally in said raceways.