Patent Publication Number: US-6907674-B2

Title: Electrical conduit layout template

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
   This application is a continuation in part of application Ser. No. 29/182,926 filed on Jun. 2, 2003, now abandoned and entitled “Electrician Centerline Template”, which is incorporated herein by reference and which is a continuation of application Ser. No. 29/161,790, filed on Jun. 5, 2002 and entitled “Electrician&#39;s Centerline Template” (now Design Pat. No. D475,307). 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to the field of stencils for use in the construction industry. In particular, the present invention relates to a template for laying out multiple entry holes for passage of conduit into an electrical panelboard. 
   In the construction industry, electrical wires are often run through piping to safely deliver power to and from a panelboard and then onto different areas of a building. This piping, referred to as “conduit” in the trade, is typically constructed from metal or plastic and comes in a variety of sizes standard to the electrical industry. The size of conduit used to run a particular electrical line depends both upon the length of the run as well as the particular power application. 
   Running conduit from a panelboard to distant areas of a building frequently requires an electrician to make numerous entry holes for passage of conduit both into and out of an electrical panelboard, as well as potentially through walls and ceilings. Often times multiple rows of columns of conduit must be installed, such as when wiring a panelboard. The configuration of the conduit is often maintained until the conduit branch off to reach different areas of a building. As such, an electrician may be required to make the same hole-cut pattern on, for example, the top surface of a panelboard and a ceiling suspended above. 
   Under the traditional method for laying out the positions of conduit entry holes on the top of a panelboard housing, an electrician uses a ruler or tape measure to measure the location of each particular entry hole. In doing so, the electrician must take into account the spacing of each conduit from a wall surface on which panelboard is located to allow for the thickness of the strut used to secure the conduit to the wall surface. In addition, the electrician must account for the spacing between each conduit, which typically conforms to industry standards such as those proscribed by the National Electrical Contractors Association (NECA). 
   The traditional method for laying out entry holes on a panelboard has several drawbacks. When multiple rows and/or columns of conduit are to be installed the task of marking the locations of the conduit entry holes can become a time consuming and tedious task. Although the electrician may need to replicate the same pattern of entry holes in multiple surfaces, each hole in each installation must be individually measured. In addition, under the traditional method, errors in measuring often occur, resulting in wasted labor and materials. 
   Measuring aids for speeding up the measurement process are known. U.S. Pat. No. 5,577,328 discloses a stencil with pre-measured markings to aid in the measuring process. The stencil is capable of measuring a variety of conduit entry hole sizes. However, an electrician using the stencil can lay out only one entry hole at a time, and must reposition the stencil before measuring an adjacent entry hole. In addition, the stencil does not account for the thickness of strut used to secure the conduit to a wall surface. Thus, the measuring process still requires a multitude of measurements and an opportunity for error exists when repositioning the template for each individual entry hole. 
   U.S. Pat. No. 4,584,780 also discloses a template for laying out conduit entry holes on an electrical panelboard. The template, however, must also be repositioned to measure each entry hole and does not account for the thickness of strut used to attach the conduit to a wall surface. 
   Given the limitations of the prior art, a more systematic measuring template and measuring method is needed to speed the accuracy and timing of conduit installations, especially for multiple-conduit installations. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention is a template for laying out electrical conduit entry hole positions on an electrical panel housing. The template is made from a sheet having a longitudinal straight edge for engaging a wall surface on which the electrical panel is fixed. The template has a spacer zone bordered on one side by the longitudinal straight edge and extending the length of the template. The width of the spacer zone in the transverse direction corresponds to the thickness of a support means used to secure the electrical conduit to the wall surface. The template also includes a marking zone which extends parallel to the longitudinal straight edge and is spaced from the longitudinal straight edge by the spacer zone. The marking zone has a width in the transverse direction corresponding to an outside diameter of a given size of electrical conduit. A plurality of apertures formed in the sheet are centered on the marking zone. The plurality of apertures form a line parallel to the straight edge and are designed to receive a tool for marking the center locations of entry holes. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top view of an electrical conduit layout template incorporating my new design. 
       FIG. 2  is a side view of the electrical conduit layout template of  FIG. 1 , the other side view being the same as that shown. 
       FIG. 3  is a bottom view of the electrical conduit layout template of FIG.  1 . 
       FIG. 4  is an end view of the electrical conduit layout template of  FIG. 1 , the other end view being the same as that shown. 
       FIG. 5  is a perspective view of the electrical conduit layout template of  FIG. 1  oriented longitudinally on the top of an electric panelboard installation. 
       FIG. 6  is a perspective view of the electrical conduit layout template of  FIG. 1  oriented transversely on the top of the electric panelboard installation of FIG.  5 . 
   

   DETAILED DESCRIPTION 
   A rectangular electric conduit layout template  10  is shown in  FIGS. 1-4 , with  FIG. 1  showing a top view of template  10 ,  FIG. 2  showing a side view of template  10 ,  FIG. 3  showing a bottom view of template  10 , and  FIG. 4  showing an end view of template  10 . 
   Template  10  is typically formed from a single piece of rectangular sheet metal, although it can also be formed from other materials such as, for example, plastic. Template  10  has a top face  11  and a bottom face  12  and a rectangular perimeter  14  consisting of longitudinal straight edges  16  and  18  and transverse straight edges  20  and  22 . Top face  11  is divided into various zones, some of which overlap. These zones include longitudinal spacer zones  24  and  26 , transverse spacer zones  28  and  30 , longitudinal marking zone  32 , and graduated marking zones  34  and  36 . Each of the marking zones  32 ,  34 , and  36  have a plurality of marking apertures  38 ,  40 , and  42 , respectively, formed therein. Template  10  also has a ruler  44  and a conduit sizing scale  46 . 
   Longitudinal straight edges  16  and  18  are parallel to one another and on opposing edges of template  10 . Transverse straight edges  20  and  22  are parallel to on another and disposed on opposite ends of template  10 . Moreover, longitudinal straight edges  16  and  18  are oriented perpendicular to transverse straight edges  20  and  22 . Spacer zones extend along each of the straight edges  16 ,  18 ,  20 , and  22 . Longitudinal spacer zones  24  and  26  extend along each longitudinal straight edge and separate a longitudinal marking zone  32  from each of longitudinal straight edges  16  and  18 . Longitudinal marking zone  32  has a width in the transverse direction corresponding to the outside diameter of a particular size of conduit. In addition, longitudinal marking zone  32  has a plurality of marking apertures  38  formed therein. Each of the plurality of marking apertures  38  is spaced from the adjacent marking aperture according to industry standards for conduit spacing. 
   Transverse spacer zones  28  and  30  extend along at least a portion of each transverse straight edges  20  and  22 . Graduated marking zones  34  and  36  abut each transverse spacer zone  28  and  30 . Each graduated marking zone  34  and  36  has a plurality of marking apertures  40  and  42  formed therein. Ruler  44  is preferably positioned along longitudinal straight edge  16  in longitudinal spacer zone  24 . In addition, a conduit sizing scale  46  is included inside longitudinal spacer zone  26  along longitudinal straight edge  18 . Ruler  44  and conduit sizing scale  46 , and any other markings on faces  11  and  12  may be either stamped or inked onto the faces. 
   In the present embodiment, width  48  of longitudinal marking zone  32  corresponds to the outside diameter of ¾ inch conduit. It is contemplated that width  48  could be of a longer or shorter length depending upon the size of conduit longitudinal marking zone  32  is designed to be used for installing. The plurality of marking apertures  38  preferably extend in a line parallel to longitudinal straight edges  16  and  18  such and centered on longitudinal marking zone  32 . Each aperture is preferably spaced a uniform distance  50  from the immediately adjacent apertures to conform to industry standards. The distance between each aperture will vary depending upon the size of conduit longitudinal marking zone  32  is designed to be used for installing. In the present embodiment the spacing between the centers of adjacent apertures is approximately an inch and three-quarters. It should be noted that although each aperture has a round profile in the present embodiment, the apertures may be of any shape capable of receiving a marking tool such as, for example, a writing utensil or scoring tool. 
   Longitudinal spacer zones  24  and  26  preferably have uniform widths in the transverse direction of approximately ¾ of an inch and 1½ inches, respectively. These widths correspond to the thickness of the struts or channels routinely used in the industry to secure electrical conduit to wall surfaces. Likewise, transverse spacer zones  28  and  30  also preferably have uniform widths in the longitudinal direction of approximately ¾ of an inch and 1½ inches, respectively, to correspond to the common strut or channel thicknesses. 
   Graduated marking zones  34  and  36  are preferably located on each transverse edge of the template immediately adjacent to the transverse spacer zones. The graduated marking zones contain a plurality of marking apertures formed in the template. Each aperture of the plurality of marking apertures  40  and  42  is spaced inward from the transverse spacer zones by a distance corresponding to the outside radius of a particular size of conduit. 
     FIGS. 5 and 6  illustrate how the template is used to mark the positions of conduit entry holes onto the housing of an electric panelboard. A perspective view of a partial panelboard installation  59  is shown in  FIG. 5. A  panelboard  60  having a top surface  62  is mounted on wall surface  64 . Strut  66  is mounted onto wall surface  64  directly above top surface  62  of panelboard  60 . In the present embodiment, strut  66  has side edges  68 ,  70 ,  72 , and  74  that are ¾ of an inch long, although side edges  68 ,  70 ,  72 , and  74  could also each be 1½ inches long. As such, front edges  76  and  78  of strut  66  are spaced outward from wall surface  64  by a distance of approximately ¾ of an inch. Thus, any conduit secured against front edges  76  and  78  of strut  66  will be spaced approximately ¾ of an inch from wall surface  64 , meaning entry holes to be cut for passage of the conduit through top surface  62  will likewise need to be spaced ¾ of an inch from wall surface  64 . 
     FIGS. 5 and 6  are examples of how template  10  can be used to lay out seven conduit entry holes: six for ¾ inch conduit and one for 2 inch conduit. First, template  10  is placed on top surface  62  so that longitudinal straight edge  16  is positioned against wall surface  64 . In this orientation, longitudinal marking zone  32  is spaced from wall surface  64  by longitudinal spacer zone  24 , which in this embodiment has a width in the transverse direction of approximately ¾ of an inch. Next, a marking tool is positioned inside of each of marking apertures  38  resulting in marks M and Mc on top surface  62  of panelboard  60 . Marks M correspond to the center point locations for the ¾ inch conduit entry holes. Once the entry holes associated with theses marks are either drilled or punched out, the entry holes will be spaced ¾ of an inch from wall surface  64 , thereby preserving the spacing needed to connect the ¾ inch conduits to strut  66 . 
   Because mark Mc is used in finding the location of an entry hole for 2-inch conduit, the center position for the entry hole must be distanced further from wall surface  64  then marks M. If the entry hole were formed centered on mark Mc, then the entry hole would be closer than ¾ of an inch to wall surface  64 . In order to make an entry hole for 2-inch conduit spaced ¾ of an inch from wall surface  64 , template  10  is repositioned so that transverse straight edge  20  is flush against wall surface  64  and longitudinal straight edge  18  dissects mark Mc. A line L 1  is then marked on surface  62  along straight edge  18 . Next a marking tool is placed within one of apertures  40  (corresponding to “2 inches”) and the template and marking tool are dragged towards the right along wall surface  64 , thereby forming a line L 2 . The lines L 1  and L 2  intersect at a point P, which is the point at which the center of a 2-inch conduit entry hole should be made. By centering the entry hole on point P, the 2 inch conduit will be space ¾ of an inch from wall surface  64 . 
   The above example illustrates some of the ways in which the present invention is superior to the templates disclosed in the prior art. Unlike the templates disclosed in the prior art, the present template does not need to be repositioned between marking the location of each entry hole. In fact, the only time the present template needs to be repositioned is when making an entry hole sized differently then the longitudinal marking zone  32 . Moreover, the spacer zones of the present invention eliminate the step of having to make an additional set of measurements to space the entry holes from the wall surface on which the panelboard is mounted. 
   Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.