Abstract:
A combination outlet box is disclosed which allows for the termination of both line and low voltage field wiring at the same location within a standard single gang electrical outlet box opening. In addition, the combination outlet box allows for a variety of configurations for routing the line and low voltage field wiring while providing the required separation between line and low voltage field wiring. The combination outlet box also provides for sufficient outlet box volume for both line and low voltage field wiring.

Description:
BACKGROUND 
   This invention relates to a combination electrical outlet box and more specifically a combination electrical outlet box with multiple chambers for both line and low voltage field wiring. 
   In many newer electrical installations, there is a need to have both high voltage and low voltage circuits terminating at the same location. One such example could be an electrical wiring device which is supplied by standard 120 VAC residential power and is controlled by a low voltage signal circuit. In this instance, both line and low voltage circuits would terminate at the same point. However, Section 725.55 of the National Electric Code (NEC) requires that the two voltages be isolated from one another by separate enclosures, barriers, or the like. 
   It is an object of this invention to provide for a convenient termination point for both line and low voltage circuits while maintaining the required separation between the two levels of voltages. 
   It is another object of this invention to provide sufficient box volume for each circuit. 
   SUMMARY 
   The present combination outlet box incorporates separate boxes for both line and low voltage field wiring. The flush box, which is intended to sit flush with the sheetrock in a typical installation, has a volume in which the line voltage field wiring is terminated in a similar manner as a standard electrical box for a receptacle, switch, or the like. In addition, the flush box also contains an enclosed channel which runs up one of the sides of the flush box for routing of low voltage field wiring while maintaining the required separation from the line voltage field wiring. 
   In addition to the flush box, there is also a recessed box which sits behind the sheetrock wall and the flush box in the typical installation. The recessed box accommodates the low voltage field wiring. Alternatively, a moveable barrier may be installed in the recessed box separating it into two separate volumes. In this configuration, the recessed box can contain both line and low voltage field wiring. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an embodiment of the combination outlet box. 
       FIG. 2  is a top view of another embodiment of the combination outlet box. 
       FIG. 3  is an exploded perspective view of the embodiment shown in  FIG. 2 . 
       FIG. 4  is an exploded perspective view of another embodiment of the combination outlet box. 
       FIG. 5A  is a top view of the flush box shown in  FIG. 2 . 
       FIG. 5B  is a bottom perspective view of the flush box shown in  FIG. 2 . 
       FIG. 6  is a perspective view of the moveable barrier shown in  FIGS. 1 ,  3 , &amp;  4 . 
       FIG. 7A  is a perspective view of the recessed box shown in  FIGS. 2 ,  3 , &amp;  4 . 
       FIG. 7B  is another perspective view of the recessed box shown in  FIGS. 2 ,  3 , &amp;  4 . 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a perspective view of the combination outlet box  50 . The combination outlet box contains three separate main parts, each of which may be formed integrally from molded plastic: a flush box  100 , a recessed box  600 , and, optionally, an L-shaped moveable barrier  1100 . 
   The flush box  100  resembles a standard plastic electrical box typically used to house an electrical wiring device such as a receptacle, switch, or the like. In addition, the dimensions of the flush box  100  are substantially the same as a standard plastic electrical box. The flush box  100  incorporates four (4) sides: a first long side  150 , a second long side  200 , a first short end  250  and a second short end  300 . In addition, the flush box also includes a first slanted member  350  and a second slanted member  400 . These two slanted members,  350  and  400  respectively, project diagonally, towards each other, from the first and second short ends,  250  and  300 , respectively. Furthermore, the flush box  100  also includes a bottom  450 . The two sides, two ends, two slanted members, and bottom define the flush box volume  550  into which an electrical device can be installed. The top edges of the two sides and the two ends away from the bottom member define the flush plane  575  where the face of the installed wiring device will lie once the installation is complete. Optionally, the flush box  100  can be comprised of just the two sides, two ends, and a bottom; omitting the two slanted members. In this fashion the flush box is simply rectangular. 
   Referring to  FIG. 5A , the first short end  250  contains a first device mounting boss  260  and the second short end  300  contains a second device mounting boss  310 . An electrical wiring device can be fixed to the flush box  100  with the use of standard mounting screws threaded into the first and second device mounting bosses,  260  and  310 , respectively. 
   Referring to  FIGS. 2 ,  3 , and  5 A, the first slanted member  350  may optionally contain one or more wiring knockouts  360  so that the external field wiring may enter into the flush box volume  550  to connect with the wiring device that is installed in the flush box  100 . The second slanted member  400  may also optionally contain one or more wiring knockouts  410  for receiving the field wiring. 
   Referring to  FIGS. 3 ,  4 ,  5 A and  5 B, the flush box  100  is integrally formed with a rectangular midway flange cover  500  which projects outward from the first short end  250 , the second short end  300 , and the first long side  150  of the flush box  100 . The midway flange cover  500  is disposed at approximately midway along the first short end  250 , the second short end  300 , and the first long side  150  of the flush box  100 . Near the corners of the midway flange cover  500  are four (4) recessed box mounting holes  510 . Surrounding each of the holes  510 , on the underside of the midway flange cover  500  is a boss to provide added strength around each hole. The midway flange cover  500  is what is used to mount the flush box  100  to the recessed box  600 . 
   Referring to  FIGS. 7A and 7B , the recessed box  600  is comprised of five main elements: a first long side  650 , a second long side  700 , a first short end  750 , a second short end  800 , and a bottom  850 . These five main elements define the recessed box volume  900 . The five main elements of the recessed box  600  are sized such that the recessed box volume  900 , minus the portion of the recessed box volume  900  occupied by the flush box  100  when the flush box  100  is mounted to the recessed box  600 , is at least equal to the volume of the flush box volume  550 . Near the corners of the recessed box  600  are located four (4) flush box mounting bosses  860 . 
   The first long side  650  and the second long side  700  may each optionally contain one or more knockouts  660  and  710 , respectively, for receiving the field wiring (refer to  FIG. 7A ). Likewise, the first short end  750  and the second short end  800  may also contain one or more knockouts  760  and  810 , respectively, for receiving the field wiring. 
   Referring to  FIG. 2 , the second long side  700  of the recessed box  600  is longer than and coplanar with the second long side  200  of the flush box  100 . The first long side  650  of the recessed box  600  is longer than and parallel to the first long side  150  of the flush box  100 . The first and second short ends  750  and  800  of the recessed box  600  are longer than and parallel with the first and second short ends  350  and  400  of the flush box  100 , respectively. The relation between the recessed box  600  and the flush box  100  is such that, while looking at the flush plane  575 , the flush box  100  lies within the recessed box  600  and is positioned generally midway in the longer dimension and sitting on the second long side  700  of the recessed box. The fact that the second long side  200  of the flush box  100  is coplanar with the second long side  700  of the recessed box  600  allows the second long side  200  of the flush box  100  to sit up directly against a building stud once the combination outlet box is installed as intended, as is the case with a standard electrical box. 
   The midway flange cover  500  of the flush box  100  is mounted onto the recessed box  600  through the use of four (4) threaded screws which are passed through the four recessed box mounting holes  510  on the midway flange cover  500  and threaded into the four flush box mounting bosses  860  on the recessed box  600 . 
   Referring to  FIG. 6 , the optional L-shaped moveable barrier  1100  is an integral planar piece of molded plastic. It may be described as having a horizontal thin arm  1150  and a vertical thick arm  1200 . The horizontal thin arm  1150  and the vertical thick arm  1200  project at a right angle from each other. The moveable barrier may optionally contain one or more knockouts  1210 . 
   Prior to assembling the flush box  100  to the recessed box  600 , the L-shaped moveable barrier  100  may be optionally be placed in the recessed box  600 . If present, the L-shaped moveable barrier  1100  would be placed inside the recessed box  600  in a plane parallel to the first and second short ends,  750  and  800 , respectively, of the recessed box  600  so as to separate the recessed box volume  900  into two separate volumes. The L-shaped moveable barrier  1100  is held in place by three separate racks which allow its position within the recessed box  600  to be adjusted. The first rack is the full height vertical rack  670  located on the first long side  650  of the recessed box  600 . This rack positions the vertical thick arm  1200  of the L-shaped moveable barrier  1100 . The second rack is the partial height vertical rack  720  located on the second long side  700  of the recessed box  600 . This second rack positions the horizontal thin arm  1150  of the L-shaped moveable barrier  1100 . The third rack is the horizontal rack  460  located on the underside of the bottom  450  of the flush box  100 . 
   Referring to  FIGS. 5A and 5B , there is a wiring channel  270 , which has a first end  280  and a second end  290 , for low voltage field wiring located in the interior of the flush box  100 . The flush box volume  550  (aside from the volume taken up by the wiring channel  270 ) is to be used for the line voltage field wiring. The wiring channel  270  is to be used for the low voltage field wiring. The wiring channel  270  runs vertically along the first short end  250  of the flush box  100  from the first slanted member  350  to about halfway up the first short end  250  (at roughly the same level as the midway flange cover  500 ). This wiring channel  270  may have a cross-section similar to a U-shape with the ends of the “U” connected to the first short end  250 . There is an opening on the underside of the first slanted member  350  leading into the second end  290  of the wiring channel  270  and an opening on the first end  280  of the wiring channel  270  leading into the flush box volume  550  The first end  280  of the wiring channel  270  lies at a point just behind where the back of an installed wiring device would be. 
   With the wiring channel  270  constructed as just described, low voltage field wiring can be run from outside the recessed box  600 , through one of the knockouts  660 ,  710 ,  760 , or  810 , into the recessed box volume  900 , through the second end  290  of the wiring channel  270  of the flush box  100 , up through the wiring channel  270  and out of the first end  280  of the wiring channel  270  and directly into the wiring device installed in the flush box  100 . The walls of the wiring channel  270  provide the required separation between the low voltage field wiring and the line voltage field wiring. 
   The recessed box volume  900  can be used in one of two configurations. The first configuration would be where the entire recessed box volume  900  is to be used exclusively for the low voltage field wiring. In this case, the L-shaped moveable barrier  1100  can simply be omitted in the installation. Optionally, the L-shaped moveable barrier  1100  can be used with one or more of its knockouts  1210  removed. In this manner, the L-shaped moveable barrier would be used to aid in positioning the low voltage field wiring in a neat manner. 
   The second configuration of the recessed box volume  900  would be where a portion of the volume would be used for low voltage field wiring and the remaining portion would be used for line voltage field wiring. In this case, the L-shaped moveable barrier  1100  would be mandatory to provide the required separation of circuits. Further, if the moveable barrier contains one or more knockouts  1210 , every such knockout  1210  would be required to not be removed. Therefore, the moveable barrier would be a solid wall with the absence of any openings in it. In this second configuration, low voltage field wiring would enter the side of the recessed box  600  below the opening for the second end  290  of the wiring channel  270 . The low voltage field wiring would then enter the second end  290  of the wiring channel  270  and then up to the first end  280  of the wiring channel  270  and to the back of the installed wiring device. The line voltage field wiring would then enter into the other side of the recessed box volume  900  and up through a knockout in the flush box  100  directly into the flush box volume  550  and into the wiring device. 
   For the construction of both the flush box  100  and the recessed box  600  there are three different embodiments. Referring to  FIGS. 2 ,  3 ,  5 A, and  5 B, for the first embodiment, the second long side  200  of the flush box  100  is a solid wall for the portion of the second long side  200  above the midway flange cover  500 . Below the midway flange cover, the second long side  200  is absent. This is because the space is taken up by the second long side  700  of the recessed box  600  (since the second long side  200  of the flush box  100  and the second long side  700  of the recessed box  600  are coplanar). Therefore, referring to  FIGS. 2 ,  3 ,  7 A, and  7 B, in this first embodiment, the second long side  700  of the recessed box  600  is in the shape of a full rectangular wall. 
   Referring to  FIG. 1 , for the second embodiment, the second long side  200  of the flush box  100  is a full solid wall both above and below the midway flange cover  500 . The portion of the second long side  200  of the flush box  100  below the midway flange cover  500  has a perimeter  220 . Since the second long side  200  of the flush box  100  and the second long side  700  of the recessed box  600  are coplanar, there needs to be a cutout  730  in the second long side  700  of the recessed box  600  to accommodate the second long side  200  of the flush box  100 . This cutout  730  includes a tongue  740  along the edge  735  of the cutout  730 . The tongue  740  matches a corresponding groove  230  on the perimeter  220  of the second long side  200  of the flush box  100 . This is such that the second long side  200  of the flush box  100  and the second long side  700  of the recessed box  600  form a single solid wall when the flush box  100  is mounted to the recessed box  600 . 
   Referring to  FIG. 4 , the third embodiment, is the same as the first embodiment except that a large portion of the second slanted member  400  of the flush box  100  is cutout such that there is a large opening  430  between the flush box  100  and the recessed box  600  (instead of a knockout). This third embodiment is only valid when the recessed box volume  900  is separated into two portions for low voltage and line voltage field wiring, respectively. Here the second slanted member  400  would be positioned directly above the portion of the recessed box volume  900  that is dedicated to the line voltage field wiring.