Patent Publication Number: US-6986673-B2

Title: Grounding clamp for raised floor

Description:
This application claims priority from provisional application Ser. No. 60/561,107, filed on Apr. 9, 2004. 

   FIELD OF THE INVENTION 
   The present invention relates to a grounding clamp for electrically and mechanically connecting an electrical conductor to a grounding post. More particularly, the present invention relates to a grounding clamp for attaching wires to a grounding post in raised floor applications. 
   BACKGROUND OF INVENTION 
   Grounding of electrical systems is a practice which accomplishes multiple functions. Foremost among these functions is protection from shock hazard due to lightning, power surges, ground faults and inadvertent contact with high voltage lines. To prevent personal injury due to such electrical hazards, it has long been known in the electrical field to use low resistance ground connections to earth. 
   However, with the advent and widespread use of highly sensitive computer components, grounding has also been found to be necessary for the reliable operation of such components. Typically, computers and other advanced data processing equipment are located and operated in a dedicated room or area in a commercial building. These rooms are usually well air-conditioned to prevent over-heating of the equipment and, consequently, these rooms have a low-humidity level. Computer operators and other personnel working in these areas can create a build-up of static electricity in their body as a result of movement in this dry environment. Subsequent contact with static sensitive computer equipment can dissipate this static charge through the equipment, impeding its operating reliability and performance. Therefore, static shielding of computer equipment is highly desirable. Further, the signal frequencies of high speed computers reach and exceed 10 megahertz. The radiation of these high frequencies can also be troublesome to computer operation. Accordingly, shielding of computer circuits from such signal “noise” is also advantageous. 
   One method currently practiced for providing signal and static grounding uses a signal reference grid beneath the floor supporting the computer equipment. The signal reference grid, which is typically run beneath a raised floor, is electrically connected along its length to the various computer components and at one end to earth, either directly or indirectly. This provides adequate signal grounding to reduce signal “noise” radiated at high frequencies. The signal reference grid is also useful in providing static protection for the computer hardware. The raised flooring in a computer area is typically formed of a semi-conductive material, and is supported on modular floor supports made of steel or aluminum. It is desirous to electrically connect the floor supports to the signal reference grid so that the floor and the computer terminals are at the same electrical potential. A computer operator standing on the semi-conductive floor will then be at the same electrical potential as the computer terminal, eliminating any chances of static dissipation between the operator and the terminal. 
   The art has seen various types of grounding connectors and other devices which connect one cable to another. Examples of these are shown in U.S. Pat. No. 1,276,228 to Keenan et al. and U.S. Pat. No. 2,786,192 to Woolley, Jr. The grounding clamps that are currently in use attach single grounds and multiple grounds to the grounding clamp in a variety of different ways. Typically, these grounding clamps consist of a holding device for receiving the wire and a tightening bolt to secure it in place. Some styles of grounding clamps require special tools for assembly and installation, which can only be purchased from the manufacturer. Grounding clamps with multiple branches for connecting a plurality of grounding wires are always preferable over a single unit. However, many of the grounding clamps currently available can only be used with a limited range of wire sizes, for example 4 to 8 AWG. Also, many of the grounding clamps currently available can only be used with grounding posts within a limited range of sizes. For example, these grounding clamps can be used with a ⅞-inch or 1-inch grounding post, but cannot be used with a ½-inch or 1½-inch grounding post. Accordingly, there is a need for a grounding clamp that can be used to connect multiple wires of different sizes and that can be used with grounding posts that have a wide range of sizes. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, an electrical grounding clamp which connects one or more grounding lines (either wires or cables) to a grounding post is provided. The grounding clamp includes: a top section having an aperture; a pair of opposing side walls extending downwardly from the top section; at least one member, preferably a pair of members, extending downwardly from each of the side walls; and a clamping bolt extending through the aperture in the top section. Each member has a bottom seating surface adapted to accommodate a grounding line. 
   The top section and the side walls are adapted to receive a grounding post. When the grounding lines are installed and the clamping bolt tightened, the grounding lines electrically and mechanically contact the bottom seating surfaces. In preferred embodiments, either the aperture in the top section is threaded and engages the clamping bolt or a wire nut tensioner having a threaded opening accommodates the clamping bolt. The top section and wire nut tensioner act cooperatively to form a pair of clamps which are adapted to accommodate grounding lines. 
   The grounding clamp can also include at least one grounding post adapter clip, preferably a pair of grounding post adapter clips (also referred to herein as post adapters), which are positioned between at least one of the side walls and the grounding post. One or both of the side walls can have one or more apertures, which are adapted to receive the adapter clips. In addition, at least one bottom seating surface, member and side wall forms at least one slot in each side wall and preferably more than one slot is formed. In addition, one or more of the bottom seating surfaces can have a lip. In another embodiment, each of the side walls has at least one notch which extends upwardly from at least one of the slots. A fitting plate or a half-fitting plate is accommodated by the slots and notches in the opposing side walls. 
   In another embodiment, the grounding clamp includes: a top section having opposing sides and an aperture, preferably located in the center; a pair of side walls extending downwardly from the opposing sides of the top section, a pair of bottom seating surfaces connected to each of the side walls; a wire nut tensioner having an opening, preferably in the center; and a clamping bolt. The clamping bolt extends through the aperture in the top section and engages the threaded opening in the wire nut tensioner. 
   The top section and the wire nut tensioner form at least one clamp, preferably a pair of clamps, which are adapted to accommodate grounding lines. The bottom seating surfaces are also adapted to accommodate grounding lines. Tightening the clamping bolt electrically and mechanically contacts the bottom seating surfaces and the clamps with the grounding lines. Preferably, the pair of side walls, the wire nut tensioner and the clamping bolt are formed from electrically conductive material. 
   The top section of the grounding clamp has first and second ends and the wire nut tensioner has opposing ends which, acting in cooperation, form one or more clamps for securing grounding lines. In preferred embodiments, the opening in the wire nut tensioner is threaded so that the clamps close when the clamping bolt is tightened and engages the wire nut tensioner. Preferably, the opening in the wire nut tensioner corresponds to the aperture in the top section when the wire nut tensioner is positioned between the side walls. 
   The grounding clamp can also include a fitting plate which extends between at least one of the bottom seating surfaces on each of the side walls. In addition, one or more of the bottom seating surfaces can have a plurality of teeth extending upwardly from the seating surfaces for penetrating the protective cover of the grounding line and electrically contacting the conductor. The grounding clamp can also include a first adapter clip and a second adapter clip, wherein the first and second adapter clips are positioned on the interior surfaces of the first and second side walls and wherein each of the side walls has an opening for engaging the adapter clips. 
   A further embodiment of the grounding clamp includes: a top section having a first end, a second end, a first side, a second side and an aperture, preferably in the center; a pair of side walls extending downwardly from the first and second sides of the top section; a wire nut tensioner having two opposing ends and a threaded opening, preferably in the center; a clamping bolt; and one or more slots in each side wall formed by the side wall, one of the members and one of the bottom seating surfaces. 
   A pair of clamps are formed by the first and second ends of the top section and the opposing ends of the wire nut tensioner acting in cooperation. The clamping bolt extends through the aperture in the top section and engages and passes through the threaded opening in the wire nut tensioner. Preferably, the top section, the pair of side walls, the wire nut tensioner, the bottom seating surfaces, the members and the clamping bolt are formed from electrically conductive material. In other preferred embodiments, the bottom seating surfaces extend outwardly from the side wall and form feet. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     Other objects and many attendant features of this invention will be readily appreciated as the invention becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
       FIG. 1  is a perspective view of a grounding clamp showing the connection of three grounding lines to a grounding post. 
       FIG. 2  is a perspective view of a grounding clamp showing the connection of four grounding lines to a grounding post. 
       FIG. 3  is an exploded perspective view of a grounding clamp showing unconnected grounding lines and a grounding post. 
       FIG. 4  is a perspective view of a grounding clamp showing the connection of the clamp to a grounding post. 
       FIG. 5  is an end view of a grounding clamp showing two post adapters between a grounding clamp and a grounding post. 
       FIG. 6  is a perspective view of a grounding clamp showing the connection of two grounding lines to a grounding post. 
       FIG. 7  is an end view of a grounding clamp showing two post adapters between the grounding clamp and a grounding post and the connection of one grounding line to the grounding post. 
       FIG. 8  is a detail view of the teeth on the bottom seating surface of a grounding clamp and shows the teeth engaging a grounding line. 
       FIG. 9  is a perspective view of a grounding clamp showing the connection of four grounding lines to a grounding post. 
       FIG. 10  is an end view of a grounding clamp showing two post adapters between the grounding clamp and a grounding post and the connection of two grounding lines to the grounding post. 
       FIG. 11  is a perspective view of a grounding clamp showing the connection of three grounding lines to a grounding post. 
       FIG. 12  is an end view of a grounding clamp showing two post adapters between the grounding clamp and a grounding post and the connection of two grounding lines to the grounding post. 
       FIG. 13  is an end view of a grounding clamp showing the connection of two grounding lines. 
       FIG. 14  is an end view of a grounding clamp showing two post adapters between the grounding clamp and a square grounding post and the connection of one grounding line. 
       FIG. 15  is an end view of a grounding clamp showing two post adapters between the grounding clamp and a round grounding post and the connection of one grounding line. 
       FIG. 16  is an end view of a grounding clamp showing two post adapters between the grounding clamp and a square grounding post and the connection of one grounding line. 
       FIG. 17  is a perspective view of a fitting plate with a pair of members extending outwardly on each side. 
       FIG. 18  is a perspective view of a half-fitting plate with one member extending outwardly on each side. 
       FIG. 19  is a perspective view of a grounding clamp showing four members of a fitting plate inserted between a grounding post and the bottom seating surfaces. 
       FIG. 20  is a side view of a grounding clamp showing a fitting plate inserted between a grounding post and a grounding line on one side and the bottom seating surfaces on the other side. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention is a grounding clamp that provides ease and flexibility for electrically and mechanically connecting one or more electrical grounding lines to a grounding post. The grounding clamp is designed for use in new or existing raised floor applications and removable adapter clips positioned on the interior side walls enable the clamp to fit a wide range of grounding post shapes and sizes. The grounding clamp allows for multiple grounding lines to be configured parallel to or perpendicular to the grounding cable run, and holds up to two pairs of grounding lines, i.e. wires or cables ranging from 0 AWG to 3000 kcmil in size, preferably from 0 to 8 AWG in size. 
   When fastening the grounding clamp to the grounding post, wire nut tensioners with different size seating surfaces are used to ensure that cables of all sizes can be properly secured to the grounding clamp. In one embodiment, teeth are placed on one or more of the four main seating surfaces of the grounding clamp. These teeth penetrate the sheath or other protective covering on insulated wires when the grounding clamp is assembled and electrically connect the conductor in the wire or cable to the grounding clamp. This allows grounding lines to be connected to the grounding clamp without first stripping the outer sheathing to expose the conductor. The teeth pass through the insulation on the grounding line and the clamping bolt is tightened until proper electrical connectivity is achieved. 
   The grounding clamp allows multiple grounding lines to be attached to a single grounding post, whether the grounding post is parallel to or perpendicular to the grounding lines. The grounding clamp also provides a secure electrical and mechanical connection between the grounding lines and the grounding clamp in both the top section and the bottom seating surfaces in the bottom section. 
   Additional flexibility is provided by grounding post adapter clips which allow a single grounding clamp to be used with grounding posts of various sizes. The adapter clips are inserted between the side walls of the grounding clamp and a grounding post when the grounding post does not a sufficient cross-sectional width to contact both of the side walls. In preferred embodiments, the side walls have one or more apertures for receiving the adapter clips. Most preferably, the adapter clips have a “snap fit” so that the apertures frictionally engage the adapter clips and hold them in position. Grounding clamps currently in use are not adaptable to different size grounding posts and, as a result, the grounding clamps are limited to a relatively few applications or are not securely held in place. 
   The wire nut tensioner has two primary functions. It forms a pair of opposing force clamps for the ground wires connected to the top section of the grounding clamp, while at the same time it forces the grounding post against the grounding wires connected to the bottom section of the grounding clamp. Grounding clamps currently in use lack this feature, making it cumbersome to attach the grounding lines to the top section without first securing the grounding clamp to the grounding post. 
   The grounding clamp is installed by positioning it over a grounding post so that the side walls of the grounding clamp extend below the grounding post. The grounding lines are then placed in the top and bottom seating surfaces of the grounding clamp. (For the purposes of this disclosure, the term “grounding line” refers to any cable or wire, either insulated or stripped of insulation, which can be used to conduct electricity, and is not intended to limit the type of electrical conductors that may be used in any way.) The clamping bolt is tightened to torque specification to secure the grounding lines in the grounding clamp and to electrically and mechanically contact the grounding lines to the grounding post. 
   The grounding clamp, including the top section, side walls, wire nut tensioner, adapter clips, clamping bolt and all of the other component parts which are described in more detail below, are constructed of an electrically conductive metal such as copper or aluminum and can be plated with a material known by those skilled in the art for plating electrical devices, such as tin. 
   Referring now to  FIG. 1 , there is shown a perspective view of a grounding clamp  10  connecting three grounding lines  91 ,  92 ,  93  to a grounding post  90 . The grounding clamp  10  includes a top section  12  having a first end  14  and a second end  15 , two sides  16 ,  17  that preferably curve downwardly and an opening  13  in the center for receiving, but not engaging, a threaded bolt  50 . The two ends  14 ,  15 , of the top section  12  preferably extend beyond the sides  16 ,  17  and have seating surfaces on the bottom for engaging grounding lines  91 ,  92 . Each of the two sides  16 ,  17  of the top section  12  is joined to a side wall  18 ,  19  which extends downwardly. Two members  20 ,  22  ( FIG. 3 ) extend from the bottom of the first side wall  18  to form two bottom seating surfaces  30 ,  32  for receiving grounding lines  91 ,  93 . Two members  21 ,  23  ( FIG. 3 ) also extend from the bottom of the second side wall  19  to form two bottom seating surfaces  31 ,  33  for receiving grounding lines  91 ,  93 . In a preferred embodiment, these seating surfaces  30 ,  31 ,  32 ,  33  are openings in the side walls  18 ,  19 , most preferably slots  24 ,  25 ,  26 ,  27  ( FIG. 3 ). The seating surfaces  30 ,  31 ,  32 ,  33  can also extend outwardly from the side wall members  20 ,  21 ,  22 ,  23  to form feet  34 ,  35 ,  36 ,  37  ( FIG. 3 ). The feet  34 ,  35 ,  36 ,  37  may include a plurality of metal teeth  38 ,  39 ,  40 ,  41  that penetrate the insulation on the grounding line  91 ,  93  and form an electrical connection between the grounding line  91 ,  93  and the grounding clamp  10 . 
   A wire nut tensioner  60  is positioned between the two side walls  18 ,  19  and it has a substantially flat center section which extends outwardly and upwardly to form two opposing ends  62 ,  63  ( FIG. 4 ), which correspond to the first and second ends  14 ,  15  of the top section  12 . The opposing ends  62 ,  63  of the wire nut tensioner  60  act in cooperation with the first and second ends  14 ,  15  of the top section  12  to form a first and a second clamp  66 ,  67  ( FIG. 4 ). These clamps  66 , 67  are adapted to accommodate grounding lines. The center of the wire nut tensioner  60  has an opening (not shown), preferably a threaded opening, which engages the clamping bolt  50 . When the bolt  50  is tightened, the wire nut tensioner  60  moves towards the top section  12  and the clamps  66 ,  67  close to secure the grounding lines to the grounding clamp. 
   The clamping bolt  50  has a first end  52  ( FIG. 10 ) which passes through the aperture  13  in the top section  12  and then through an opening (not shown) in the wire nut tensioner  60 . As stated above, the opening in the wire nut tensioner  60  is, preferably, threaded and engages the threads on the bolt  50 . After the clamping bolt  50  passes through the wire nut tensioner  60 , a nut or a terminating pad  58  ( FIG. 5  and  FIG. 14 ) can be attached to the first end  52 , or first end  52  can be employed without a terminating pad  58  ( FIG. 15 ). The nut or terminating pad  58  frictionally engages the grounding post  90  to secure the grounding clamp  10  in position. In some embodiments, the nut or terminating pad  58  can be used without a wire nut tensioner  60  as shown in  FIG. 15 . The second end of the clamping bolt  50  has a standard hexagonal bolt head  56  which can be used with a variety of standard wrenches to turn, i.e. rotate, the clamping bolt  50 . In preferred embodiments of the invention, a device for manually tightening the clamping bolt  50 , such as a handle or a wheel, can be attached to the second end of the clamping bolt  50  in place of the hexagonal bolt head  56 . When the grounding clamp  10  is installed, the clamping bolt  50  is rotated so that the nut or terminating pad  58 , or the first end  52  itself, engages the surface of the grounding post  90 . The rotation of the clamping bolt  50  also causes the wire nut tensioner  60  to move upwardly, towards the top section  12 . 
   An installed grounding clamp  10  is shown in  FIG. 2  with four grounding lines  91 ,  92 ,  93 ,  94  connected to a grounding post  90 . This illustrates how the grounding lines  93 ,  94  are connected to the bottom seating surfaces  30 ,  31  and  32 ,  33  ( FIG. 3 ) and the grounding clamp  10  is secured to the grounding post  90  when the clamping bolt  50  is tightened. The clamping bolt  50  serves two functions. First, tightening the clamping bolt  50  causes the wire nut tensioner  60 , in cooperation with the top section  12 , to secure the two grounding lines  91 ,  92 . Second, the clamping bolt  50  contacts the grounding post  90  and forces it against the grounding lines  93 ,  94 , which in turn secures and electrically contacts the grounding lines  93 ,  94  to the bottom seating surfaces  30 ,  31 ,  32 ,  33  of the grounding clamp  10 . 
     FIG. 3  shows an exploded view of the grounding clamp  10  as well as the grounding post  90  and grounding lines  91 ,  92 ,  93 ,  94 .  FIG. 3  illustrates how the grounding post  90  is positioned between the side walls  18 ,  19  of the grounding clamp  10  and the ground lines  93 ,  94  are positioned in slots  26 ,  27  and  24 ,  25 , respectively. Preferably, at least one grounding line  93  or  94  passes through a pair of the bottom seating surfaces  30 ,  31  or  32 ,  33  to maintain the grounding clamp  10  in position. 
   Side wall  19  has members  21 ,  23  which extend downwardly and then laterally to form slots  25 ,  27  with bottom seating surfaces  31 ,  33  located on the bottom side of the slots  25 ,  27 . Similarly, side wall  18  has members  20 ,  22  which form slots  24 ,  26  with bottom seating surfaces  30 ,  32 . In a preferred embodiment, the slots  24 ,  25 ,  26 ,  27  have lips  42 ,  43 ,  44 ,  45 , which engage the grounding lines when they are positioned on the seating surfaces  30 ,  31 ,  32 ,  33 . 
   When the clamping bolt  50  is tightened, the grounding post  90  is forced against the grounding lines  93 ,  94  and secures them in the grounding clamp  10 . Grounding lines  91 ,  92  are inserted in the clamps  66 ,  67  formed by the top section  12  and the wire nut tensioner  60 . When the clamping bolt  50  is rotated, the first end  52  or terminating pad  58  of the bolt  50  contacts the grounding post  90  and the wire nut tensioner  60  moves upwardly to secure the grounding lines  91 ,  92  in the first and second clamps  66 ,  67 . At the same time, the upward movement of the wire nut tensioner  60  causes the grounding lines wires  93 ,  94  to contact the bottom seating surfaces  30 ,  31 ,  32 ,  33  and the grounding post  90 .  FIG. 4  shows a grounding clamp  10  positioned on a grounding post  90  prior to the connection of the grounding lines and before the clamping bolt  50  is tightened. 
     FIG. 5  shows an end view of the grounding clamp  10  with a convex top section  12  and substantially parallel side walls  18 ,  19 . The feet  34 ,  35  extend outwardly from the side walls  18 ,  19 , respectively, to provide additional surface area for electrically and mechanically engaging the grounding lines that are connected to the grounding clamp  10 . A pair of grounding post adapter clips  82 ,  83  are positioned between the grounding post  90  and the side walls  18 ,  19  to provide a tight fit. The widths of the adapter clips  82 ,  83  can vary in order to accommodate different size grounding posts. This allows the grounding clamp  10  to be adapted for use with grounding posts  90  having various sizes and shapes. In preferred embodiments, the side walls  18 ,  19  have one or more apertures  84 ,  85  that are used for securing the adapter clips  82 ,  83  in position. 
     FIGS. 6 ,  9  and  11  show grounding clamps  10  connecting grounding posts  90  to different numbers of grounding lines  91 ,  92 ,  93 ,  94 . These figures show how tightening the clamping bolt  50  simultaneously secures the grounding clamp  10  to the grounding lines  91 ,  92 ,  93 ,  94  and the grounding post  90 . 
     FIGS. 7 ,  10  and  12  show end views of the grounding clamp  10  connecting grounding lines  91 ,  94  to grounding post  90 .  FIGS. 7 and 12  show the grounding clamp  10  before the clamping bolt  50  is tightened. The clamping bolt  50  is not in contact with the grounding post  90  and the grounding post  90  is not in contact with the grounding lines  91 ,  94 .  FIG. 10  shows the grounding clamp  10  after the clamping bolt  50  has been tightened and the grounding lines  91 ,  94  secured to the grounding clamp  10 .  FIG. 10  shows how the downward force of the clamping bolt  50  on the grounding post  90  secures and electrically contacts the grounding line  94  to the bottom seating surfaces  30 ,  31 . At the same time, the first clamp  66  of the top section  12  is connected to another grounding line  91 .  FIG. 10  also shows the adapter clips  82 ,  83  protruding through the apertures  84 ,  85  in the side walls  18 ,  19  to secure them in place. 
     FIG. 10  illustrates how the clamping bolt  50  locks the grounding clamp  10  into position. As the clamping bolt  50  is turned, it engages the wire nut tensioner  60  and contacts the grounding post  90 , pushing against the grounding post  90  and forcing it into electrical contact with the grounding line  94  positioned in the bottom seating surfaces  30 ,  31 . At the same time, the rotation of the clamping bolt  50  causes the wire nut tensioner  60  to move upwardly and, acting in cooperation with the top section  12 , secures the grounding line  91  in clamp  66 . 
     FIG. 8  shows a detail of one of the bottom seating surfaces  31  of the grounding clamp  10 . In this preferred embodiment, a foot  35  with a plurality of teeth  39  extends outwardly from the seating surface  31  to provide an increased seating surface. When the grounding clamp  10  is installed and the clamping bolt  50  tightened, the teeth  39  penetrate the grounding line  94  and provide an electrically conductive path between the grounding line  94  and the grounding clamp  10 .  FIG. 8  also shows the bottom member  21  of the side wall which, together with seating surface  31 , forms a slot  25  for receiving the grounding line  94 . The bottom of the slot  25  has a lip  43  which prevents the grounding line  94  from moving out of the slot  25  when the grounding clamp  10  is secured to the grounding post  90 . 
     FIGS. 13–16  show how the grounding clamp  10  can be used with grounding posts  90  having different shapes and sizes. Electrically conductive grounding post adapter clips  82 ,  83  are positioned between the side walls  18 ,  19  of the grounding clamp  10  and the grounding post  90 . Different size adapter clips  82 ,  83 , which can also have different configurations, are used with grounding posts  10  having different sizes and shapes to ensure a tight fit and an electrically conductive path between the grounding clamp  10  and the grounding post  90 .  FIGS. 13 and 15  show round grounding posts  10  having different diameters. The grounding post  90  in  FIG. 13  contacts the side walls  18 ,  19 , while the grounding post  90  in  FIG. 15  does not contact the side walls  18 ,  19  and requires adapter clips  82 ,  83 .  FIGS. 14 and 16  show square grounding posts  10  with different widths which require adapter clips  82 ,  83  in order for the grounding post  10  to electrically contact the side walls  18 ,  19 . 
     FIG. 17  shows an I-shaped fitting plate  170  with members  172 ,  174  and  176 ,  178  extending outwardly from opposing ends to form notches  173 ,  175  on the opposing sides. The fitting plate  170  is formed from electrically conductive material, preferably the same material that is used to form the top section  112  and side walls  118 ,  119  of the grounding clamp  110 . The members  172 ,  174  and  176 ,  178  of the fitting plate  170  are placed in the slots  124 ,  125 ,  126 ,  127  of the side walls  118 ,  119  ( FIGS. 19 and 20 ), respectively, after the grounding clamp  110  is positioned on the grounding post  190 . For installations of the grounding clamp that do not call for grounding lines to be installed in the bottom seating surfaces, the fitting plate is used. When the clamping bolt is tightened, the fitting plate secures the bottom of the grounding clamp to the grounding post. 
     FIG. 18  shows a half-fitting plate  270  with members  272 ,  274  extending outwardly. The half-fitting plate  270  is used when a large grounding line is installed on one side of the bottom section of the grounding clamp and a small grounding line is installed on the other side. The half-fitting plate  270  allows the smaller grounding line to be tightly secured in place when the grounding line is positioned between the members  272 ,  274  and the bottom section seating surfaces. The half-fitting plate  270  can also be used when only one grounding line is connected to the bottom seating surfaces of the grounding clamp to prevent the grounding clamp from tilting to the side. 
     FIG. 19  shows a fitting plate  170  installed between a grounding post  190  and the bottom seating surfaces of a grounding clamp  110 . When the clamping bolt  150  is tightened, the fitting plate  170  is forced against the grounding line  191 . This electrically contacts the grounding line  191  to the grounding post  190  and the grounding clamp  110  and secures the grounding line  191  in place. To install the fitting plate  170 , the members  172 ,  174  and  176 ,  178  of the fitting plate  170  are positioned in the slots  124 ,  126  and  125 ,  127  in side walls  118  and  119 , respectively. In preferred embodiments, the side walls  118 ,  119  have notches  146 ,  148  and  147 ,  149  (notch  148  is hidden by the grounding post  190 ), respectively, which correspond to and receive the members  172 ,  174 ,  176 ,  178  of the fitting plate  170 . These notches  146 ,  148  and  147 ,  149  are designed to receive the fitting plate  170  so that the fitting plate  170  does not interfere with the installation of the grounding lines  191  in the slots  124 ,  125 ,  126 ,  127 .  FIG. 19  also shows feet  134 ,  135 ,  136 ,  137  which extend outwardly from the side walls  118 ,  119  to provide additional contact surfaces for the grounding lines  191 . 
     FIG. 20  shows a grounding clamp  110  mounted to a grounding post  190  with a member  174  of the fitting plate  170  positioned between a grounding line  191  and the grounding post  190 . The member  178  on the opposing end of the fitting plate  170  is positioned on a seating surface  133  that does not have a grounding line installed.  FIG. 20  shows how the members  174 ,  178  of the fitting plate  170  can be easily inserted into slots  125 ,  127  in the side wall  119 . The members  172 ,  174 ,  176 ,  178  of the fitting plate  170  extend beyond the side walls  118 ,  119  ( FIG. 19 ) and over the feet  134 ,  135 ,  136 ,  137 . When the clamping bolt  150  is tightened, the members  172 ,  174 ,  176 ,  178  push down on the grounding line  191  so that it contacts the surface of the feet  134 ,  135 ,  136 ,  137 . 
   Thus, while there have been described the preferred embodiments of the present invention, those skilled in the art will realize that other embodiments can be made without departing from the spirit of the invention, and it is intended to include all such further modifications and changes as come within the true scope of the claims set forth herein.