Plastic channel for electrical wiring

An electrical wire support assembly for routing wire along building interior structures includes a plurality of hangers that suspend electrical wiring from building interior structures. The hangers are fastened to the interior structures in a hanger row that follows a desired wiring path. Each hanger includes a slightly trapezoidal frame section integrally connected to a fastening flange. The hangers are shaped to support electrical wires strung through the frame sections and to allow elongated plastic cover sections to snap over the frame sections. The cover sections conceal and protect the electrical wiring. C-shaped couplers fit collar-like around the joined ends of the cover sections and hold the cover sections together end-to-end. Each fastening flange includes fastener holes for receiving fasteners such as nails or screws. Side walls of each hanger frame section include an integrally outwardly extending horizontal ridge. Side walls of each cover section each include a beveled upper edge and a horizontal groove. The beveled edges help initiate outward splaying of the cover side walls as the covers are being pushed into position over the hanger frame sections. The grooves are shaped and positioned to allow the hanger frame section ridges to snap into the grooves, securing the cover sections to the hanger frame sections.

TECHNICAL FIELD 
This invention relates generally to an electrical wiring support assembly 
and, more particularly, to such an assembly adapted for use in installing 
electrical wiring in a building. 
INVENTION BACKGROUND 
Currently, electrical wiring is installed through open areas in building 
structures by first drilling holes through wooden frame elements such as 
studs (upright wall supports), joists (long horizontal supports that floor 
boards or ceiling laths are fastened to), stringers (long horizontal 
supports) and rafters (sloping roof beams). Wiring is then passed through 
the drilled holes. This process is time consuming, requires the use of a 
drill, and weakens the support members that must be drilled-through. 
Another common method for supporting wiring in a horizontal orientation 
within a building without having to drill holes in support members is to 
simply lay the wiring across the stringers and/or joists that form the 
unimproved "floor" of an attic. However, attic wiring is often subjected 
to extreme high and/or low temperatures and may be subjected to 
substantial temperature swings according to seasonal temperature 
variations experienced in most parts of the world. Temperature extremes 
and/or substantial temperature variations of this kind can shorten the 
life of materials used to insulate electrical wiring. Temperature 
variations also complicate the wiring design of a building by changing the 
ampacity ratings of wire conductors. In addition, it is hazardous for 
workers to attempt to service wiring that is supported in this way. 
Servicing attic wiring is hazardous because, to reach the wires, workers 
must sometimes attempt to walk across and stand on unimproved attic 
flooring, i.e., stringers or floor joists with no actual floorboards 
covering them. 
To facilitate the suspension of electrical wiring in buildings in general 
and the horizontal suspension of electrical wiring in particular, various 
types of support apparatus in the form of duct, channel, hanger or conduit 
systems are employed. Such suspension means allow installers to route and 
support wires beneath frame structures such as ceiling joists and 
stringers that are disposed above inhabited, temperature-controlled areas 
of a building--areas that service personnel can more readily gain access 
to. 
One example of such a system is disclosed in U.S. Pat. No. 2,917,083 issued 
Dec. 15, 1959 to Duvall et al. The Duvall et al. system includes a fully 
enclosed duct used in commercial construction to support electrical wires. 
A generally rectangular-shaped coupler connects lengths of the duct 
end-to-end. Duvall et al. also discloses a duct hanger having a fastening 
flange with holes through which fasteners such as nails may be driven into 
an external support structure such as a wooden joist or stringer. The 
system also includes an end-cap section for closing-off the open end of a 
duct. Each of the above components of the Duvall et al. system is made of 
sheet metal--a material that can be expensive and difficult to form and 
that can present problems in electrical wiring applications due to its 
high conductivity and characteristically sharp edges. In addition the 
hangers are two-piece L-shaped units that are relatively difficult to 
install, as they must be fastened together and to the duct using separate 
fastening hardware. The couplers are also relatively difficult to install 
and are also difficult to construct. The couplers are difficult to 
construct because they must be cut or stamped from sheet metal in two 
pieces then joined together at a hinged connection. The couplers are 
difficult to install because they must be fastened within and between two 
lengths of duct by separate fastening hardware. Still further, these 
hangers are limited in that they must be positioned at joints between duct 
lengths to engage studs also used to connect the couplers to the duct 
ends. In addition, because a completely enclosed duct supports the wiring, 
the system cannot be used to route certain types of nonmetallic sheathed 
cable without violating Article 336 of the National Fire Protection 
Association (NFPA) National Electrical Code. Specifically, types NM and 
NMC nonmetallic sheathed cable may not be supported within enclosed 
ducting. Unfortunately, NM-type cable is very common in residential home 
construction. 
Another example of such a system is disclosed in U.S. Pat. No. 1,992,574 
issued Feb. 26, 1935 to Jenkins. Similar to the Duvall et al. system, the 
Jenkins system includes fully enclosed duct sections with box-shaped 
cross-sections used in commercial construction to support electrical 
wires. Couplers in the form of end flanges integrally formed at the ends 
of each length of the duct are configured to join duct sections. Jenkins 
also discloses a duct hanger with a generally rectangular frame section 
and an integral fastening flange with holes through which fasteners such 
as nails may be driven into an external support structure. The system also 
includes an end-cap section for closing-off the open end of a duct. As 
with the Duvall et al. system, each of the above components is made of 
sheet metal and therefore has all the same attendant limitations. The 
Jenkins hangers are single piece units but must be fastened to end-flange 
portions of the ducts using separate fastening hardware. The coupler 
flanges make the duct forming process more difficult as they extend 
integrally outward from the ends of the ducts. To couple separate lengths 
of duct the end flanges are fastened together using separate fastening 
hardware. In addition, the hangers must be assembled to the duct at the 
same time as the duct lengths are being joined together. This is because 
the hangers must be positioned between the end flanges and are held in 
place by the same fastening hardware that joins the end flanges together. 
As with the Duvall et al. system, the fully enclosed duct of the Jenkins 
system makes it incompatible with certain non-metallic sheathed cable. 
Because of the inherent problems associated with using metal components to 
support electrical wiring, some current systems include wire suspension 
components made of plastic. One such system is disclosed in U.S. Pat. No. 
4,857,670, issued Aug. 15, 1989 to Frank et al. Frank et al. discloses 
fully enclosed PVC duct sections for supporting electrical wiring. 
Couplers in the form of tabs join the duct sections together end-to-end. 
Opposite ends of each tab are slidably received into grooves formed within 
each end of each duct section. The tabs and grooves are configured to join 
duct sections end-to-end in either linear fashion or at right angles. The 
duct sections include an integrally hinged cover that snaps into place 
over a U-shaped trough to form the fully enclosed duct with a generally 
rectangular cross-section. The grooves, the hinged cover and the snap-fit 
connection of each duct section are relatively complex and difficult to 
extrude or mold. In addition, the Frank et al. system has the same 
incompatibility problem with certain types of non-metallic sheathed cable 
as do the Duvall et al. and Jenkins systems. 
What is needed is an electrical wiring support assembly that is inexpensive 
to manufacture and easy to assemble and install without weakening building 
structures. What is also needed is such an assembly that can be used with 
types NM and NMC non-metallic sheathed cable without violating the NFPA 
National Electrical Code. Also needed is such an assembly that does not 
create or increase the risk of short-circuiting the electrical wires that 
it supports. 
INVENTION SUMMARY 
In accordance with this invention an electrical wire support assembly for 
supporting electrical wire on building interior structures is provided 
that comprises a hanger configured to support electrical wires. The hanger 
includes a frame section and a fastening flange connected to the frame 
section. The frame section is configured to support electrical wires and 
an elongated non-metallic cover section that conceals electrical wires 
supported on the hanger. The fastening flange is configured to secure the 
hanger to a building interior structure. 
According to another aspect of the invention the cover section is 
configured to fit over the hanger frame section. This configuration allows 
an installer to snap the cover into place after installing the hanger and 
running the wire through the hanger. 
According to another aspect of the invention the cover section has a 
generally U-shaped cross-section. The U-shaped cross section defines an 
elongated inner channel. The frame section of the hanger is disposed in 
the inner channel of the cover section. 
According to another aspect of the invention the assembly includes at least 
one additional elongated plastic cover section. The assembly also includes 
at least one additional hanger and at least one coupler configured to join 
the abutting ends of two cover sections together in an end-to-end 
disposition. 
According to another aspect of the invention each coupler comprises a 
collar configured to receive and join the abutting ends of two adjacent 
cover sections. This exterior collar configuration allows an installer to 
snap the collars into place over abutted ends of cover sections that have 
already been installed over the hanger frame sections and positioned 
end-to-end along the wiring path. 
According to another aspect of the invention each coupler has a generally 
C-shaped cross-section slightly larger than that of the cover sections. 
The slightly larger cross-section allows the couplers to fit around the 
abutted ends of the cover sections. 
According to another aspect of the invention each coupler includes a pair 
of parallel coupler side walls that extend integrally and generally 
perpendicularly upward from a coupler base. Each coupler side wall has an 
upper edge. A projection of a first pair of projections extend integrally 
and generally perpendicularly inward from the respective end wall upper 
edges to respective inner ends of the first pair of projections. Each 
projection of the first pair of projections extends over and engages a 
cover side wall upper edge, preventing the cover section ends from lifting 
out of the coupler. The first projection inner ends are spaced apart to 
define an upper coupler opening. 
According to another aspect of the invention each coupler includes a second 
pair of projections extending integrally and generally perpendicularly 
downward from respective inner ends of the first pair of projections. The 
downward projections further secure the coupler to the cover side wall 
upper edges. 
According to another aspect of the invention each hanger includes a 
horizontal ridge that extends integrally outwardly from along a portion of 
the frame section of each hanger. The inner channel of each cover section 
includes a longitudinal groove that is shaped and positioned to receive 
the frame section ridges. The ridges and channels cooperate to allow the 
cover sections to be snapped into position over the hanger frame sections. 
According to another aspect of the invention the U-shaped cross-section of 
each cover section has generally parallel cover side walls that extend 
generally perpendicularly upward from a cover base. Upper edges of the 
side walls define a longitudinal upper opening in each cover section. The 
cover grooves are disposed in and along respective opposite inner side 
surfaces of the respective opposite cover side walls. Each hanger frame 
section has generally parallel frame side walls that extend generally 
perpendicularly between parallel upper and lower frame walls to form a 
generally rectangular shape. The horizontal longitudinal ridges extend 
integrally outwardly from along respective outer surfaces of the 
respective frame side walls. The frame side walls and ridges are 
positioned to engage the respective cover side walls and grooves. The 
lower frame wall is positioned to engage the cover base. Each coupler has 
a generally rectangular aperture shaped to receive abutting cover section 
ends. 
According to another aspect of the invention the assembly includes at least 
one end-cap configured to attach to an end of a cover section and 
close-off an end of the cover channel. 
According to another aspect of the invention each end-cap includes a pair 
of tabs engageable with the distal ends of respective elongated grooves of 
a cover section. 
According to another aspect of the invention the frame section and 
fastening flange section of the hanger are integrally formed as a single 
unitary piece. 
According to another aspect of the invention at least one hole extends 
through a thickness of the fastening flange. The holes are included to 
receive fasteners such as nails or screws used to attach the hanger to 
interior building structures. 
According to another aspect of the invention the coupler, hanger and end 
cap are made of plastic. The use of plastic reduces the risk of electrical 
short circuits and damage to electrical insulation from sharp metal edges. 
According to another aspect of the invention a method is provided for 
installing an electrical wire support assembly on building interior 
structures. The method includes the steps of attaching the fastening 
flange of a hanger to a building interior structural member along a 
desired electrical wiring path. Electrical wiring is then passed-through 
and supported within the hanger frame section and the cover section is 
engaged onto the hanger frame section. 
According to another aspect of the invention the above method includes the 
provision of at least one additional hanger, cover section and coupler. 
The fastening flanges of the additional hangers are attached to building 
interior structural members at spaced points along the electrical wiring 
path. The fastening flanges of the additional hangers are attached to 
building interior structural members at spaced points along the electrical 
wiring path. The electrical wire is then passed-through and supported in 
the additional hanger frame section. The cover sections are then engaged 
onto the hanger frame sections and are joined by providing the couplers 
over the abutted ends of the cover sections.

PREFERRED EMBODIMENT DESCRIPTION 
An electrical wire support assembly for supporting electrical wire on 
building interior structures is generally shown at 10 in FIGS. 1 and 2. In 
FIG. 1 the assembly 10 is shown fastened across a row of floor joists 12 
that support a portion of a floor 14 in a building. The assembly 10 is 
also shown supporting and concealing suspended portions of electrical 
wires 16. FIG. 2 shows the assembly 10 alone with electrical wires 16 
removed for clarity. As shown in both FIG. 1 and FIG. 2 the assembly 10 
comprises a plurality of elongated plastic cover sections 18 arranged 
end-to-end in a cover section string 19. Each cover section 18 includes a 
longitudinal channel 20 configured to conceal and protect lengths of 
electrical wire 16 that the assembly 10 supports. As is best shown in FIG. 
2, when the cover sections 18 are joined together, the cover channels 20 
are aligned end-to-end into a single composite channel 21. The assembly 10 
additionally comprises a plurality of hangers, generally indicated at 22 
in FIGS. 1-3. Each hanger 22 includes a frame section 24 and a fastening 
flange 25 connected to the frame section 24. The hanger frame sections 24 
are configured to support both the electrical wires 16 and the cover 
sections 18. The fastening flanges 25 are configured to secure the hangers 
22 to one or more building interior structures such as stringers or joists 
12 to form a row of hangers 22 aligned with a desired electrical wiring 
path. 
As shown in FIGS. 2 and 4, each cover section 18 has a uniform, generally 
U-shaped cross-section along its length that defines the elongated inner 
channel 20. The U-shaped cross-section of each cover section 18 is formed 
by a pair of generally parallel cover side walls 26 that extend generally 
perpendicularly upward from a cover base wall 28. Although the cover side 
walls 26 are generally perpendicular to the cover base wall 28, they have 
a slight outward splay. The cover side walls 26 lean outwardly from the 
vertical by approximately 1.degree./30' to aid in allowing an installer to 
push the cover sections 18 into position over the hanger frame sections 
22. The cover side and base walls 26, 28 form rounded corners where they 
join together. Upper edges 36 of the cover side walls 26 define a 
longitudinal upper channel opening 40 into the channel 20. The inner 
facing portions 37 of the upper edges 36 are beveled to further aid in 
allowing an installer to push the cover sections 18 into position over the 
hanger frame sections 22. The cover sections 18 may be cut to any length 
to accommodate various construction requirements. 
The elongated inner channel 20 of each cover section 18 includes two 
longitudinal grooves shown at 30 in FIGS. 2 and 4. The cover section 
grooves 30 are shaped and positioned to receive two hanger ridges shown at 
32 in FIGS. 2 and 3 when an installer pushes the cover sections 18 into 
position over the duct frame sections 24. The ridges 32 are formed on 
respective outer surfaces 52 of respective frame side walls 46 of each 
hanger frame section 24. The cover grooves 30 run the entire length of the 
cover sections 18 and are disposed in and along respective inner side 
surfaces 34 of each side wall parallel to respective cover side wall upper 
edges 36. The cover grooves 30 are cut into their respective side walls 26 
approximately 1/3 the distance from the respective side wall upper edges 
36 to the cover base wall 28. The grooves 30 and ridges 32 cooperate to 
support the cover sections 18 on the frame sections 24 of the hangers 22. 
The frame section 24 of each hanger 22 can engage a cover section 18 at any 
point along the length of the cover section 18 as shown in FIG. 2. This 
gives an installer the freedom to position hangers 22 wherever support 
members happen to be located while cutting cover sections to any 
convenient length as shown in FIG. 1. In other words, an installer need 
not be concerned with positioning hangers 22 or cutting cover sections 18 
in such a way as to align hangers 22 with discrete attachment points along 
or between cover sections 18. 
The frame section 24 of each hanger 22 is disposable within the inner 
channel 20 of a cover section 18 as shown in FIG. 2. The hanger fastening 
flanges 25 extend out through the longitudinal upper channel opening 40 
defined by the open end of the U-shaped cover cross section. The hanger 
fastening flanges 25 protrude from the covers 18 to allow installers to 
attach the hangers 22 to building structural members such as joists 12 or 
stringers. Two fastener holes 42 extend through a thickness of each 
fastening flange 25. The fastener holes 42 receive fasteners such as nails 
44 or screws that are used to attach the hangers 22 to support structures. 
As best shown in FIG. 4, each hanger frame section 24 has generally 
parallel frame side walls 46 that extend generally perpendicularly between 
parallel upper and lower frame walls 48, 50 to form a generally 
rectangular shape. While the frame side walls 46 are generally parallel to 
one another, they actually splay slightly outwardly from each other. The 
frame side walls 46 of the present embodiment lean outward by 
approximately 1.degree./30' from the vertical. Therefore, the shape of the 
frame section 24 is generally rectangular, but is slightly trapezoidal. 
The horizontal longitudinal ridges 32 extend integrally outwardly from 
along respective outer surfaces 52 of the respective frame side walls 46 
of each hanger 22 as shown in FIG. 3. Each ridge 32 is generally rail 
shaped and has a generally rectangular cross-section with slightly rounded 
corners. The ridges 32 run parallel to the upper and lower walls 48, 50 of 
the generally rectangular (though slightly trapezoidal) hanger frame 
section 24 and extend along the entire length of their respective frame 
side walls 46. The ridges 32 are disposed approximately one-third the 
distance from the top to the bottom of their respective frame side walls 
46. 
The frame side walls 46 and ridges 32 are positioned to engage the 
respective cover side walls 26 and grooves 30. The lower frame wall 50 is 
positioned to engage the cover base wall 28. The frame section walls 46, 
48, 50 define a generally rectangular frame channel that electrical wires 
16 are passed through and supported from. The frame section 24 and 
fastening flange section 25 of each hanger 22 are integrally formed as a 
single unitary piece. 
As is generally indicated FIGS. 1, 2 and 6, the assembly 10 includes a 
plurality of couplers 54. Each coupler 54 is configured to join the ends 
of two cover sections 18 together end-to-end to form a cover section 
string 19. Each coupler 54 comprises a collar configured to receive and 
join the abutting ends of two cover sections 18. In other words, the 
couplers 54 hold the abutted ends of the cover sections 18 together and 
conceal the seam formed between the abutted cover section ends. 
As best shown in FIG. 6, each coupler 54 has a generally C-shaped 
cross-section slightly larger than the U-shaped cross-section of the cover 
sections 18. The inner dimensions of the coupler 54 are either 
approximately the same or slightly larger than the corresponding outer 
dimensions of the cover sections 18 so that the cover section ends can 
slide into the coupler 54. The cover ends are held in place within the 
couplers 54 either by an interference fit or by the application of a layer 
of adhesive between inner surfaces of the coupler 54 and outer surfaces of 
the joined ends of the cover sections 18. 
Each coupler 54 includes a pair of generally parallel coupler side walls 56 
that extend integrally and generally perpendicularly upward from a coupler 
base wall 58. The coupler side walls 56 and base wall 58 form rounded 
corners where they join. Each coupler side wall 56 has an upper edge 60 
and a first pair of projections 62 that extend integrally and generally 
perpendicularly inward from the respective end wall upper edges 60 and 
terminate at respective inner ends 64 of the first pair of projections 62. 
The first pair of inward projections 62 are positioned to engage, i.e., to 
hook over cover section side wall upper edges 36 and thereby prevent 
couplers 54 from dropping off the cover sections 18. The first projection 
inner ends 64 are spaced apart to define an upper coupler opening. 
Each coupler 54 includes a second, shorter pair of projections 66 that 
extend integrally and generally perpendicularly downward a short distance 
from respective inner ends 64 of the first pair of projections 62. The 
second pair of projections 66 further secure the coupler 54 to the cover 
side wall upper edges 36 by hooking onto the inner surfaces 34 of the 
cover section channels 20 and thereby resisting outward splaying of the 
coupler side walls 46. 
The assembly 10 includes generally rectangular end-caps generally indicated 
at 66 in FIGS. 1, 2 and 5. The end-caps 66 are configured to attach over 
the ends of a cover section string 19 and close-off open ends of the cover 
channels 20. Each end cap 66 includes a cap end wall 68 and two generally 
parallel cap side walls 70 that extend axially outward from the end wall 
68 and integrally upward from a cap base wall 72. The cap base wall 72 
also extends integrally and axially outward from along a base edge of the 
cap end wall 68. While the cap side walls 70 may be described as being 
generally parallel, they are actually slightly splayed to match the 
configuration of the cover sections 18. Each cap side wall 70 is tilted 
slightly outward from the vertical by approximately 1.degree./30'. 
Consequently, the shape of each cap end wall 68 is generally rectangular 
but is slightly trapezoidal. 
The cap side walls 70 and base wall 72 have interior dimensions that match 
or are slightly larger than the outer dimensions of the ends of the cover 
sections 18. Therefore, when an end cap 66 is assembled to a cover section 
18, it fits over the end of the cover section 18. Each end-cap 66 also 
includes a pair of axially extending tabs 74 that fit within the distal 
ends of respective elongated grooves 30 of a cover section 18. 
The cover sections 18, couplers 54, hangers 22 and end caps 66 are made of 
a non-metallic material such as plastic. 
In practice, an electrical wire support assembly 10 constructed according 
the present invention is installed on building interior structures by 
first nailing or screwing the fastening flanges 25 of the hangers 22 to 
building interior structural members such as stringers or joists 12. The 
hangers 22 are attached to the structural members at spaced points along a 
desired electrical wiring path. Electrical wires are then strung through 
and suspended from the frame sections of the hangers 22. The cover 
sections 18 are then snapped into place over the hanger frame sections in 
an end-to-end disposition with their respective ends abutting one another. 
The couplers 54 are then snapped over the abutted ends of the cover 
sections. An adhesive may be introduced between the couplers 54 and the 
cover sections 18 to further strengthen the joints and to prevent the 
couplers 54 from sliding lengthwise out of position. At some point in the 
assembly process, end caps 66 are pushed into place over the open channel 
ends at each respective end of the string 19 of pre-joined cover sections 
18. As with the couplers 54, an adhesive may be introduced between the end 
caps 66 and the ends of the cover sections 18. 
The above description and drawings illustratively set forth my presently 
preferred invention embodiments. I intend the description and drawings to 
describe an embodiment of the invention rather than to limit the scope of 
the invention. Obviously, it is possible to modify this embodiment while 
remaining within the scope of the following claims. Therefore, within the 
scope of the claims, one may practice the invention otherwise than as the 
description and drawings specifically show and describe.