Patent Publication Number: US-7591656-B1

Title: Grounding terminal block assembly for multiple services

Description:
This application is a Continuation-In-Part of U.S. patent application Ser. No. 12/287,244 filed Oct. 7, 2008 now U.S. Pat. No. 7,527,467 and still pending the entire contents of which are incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates to terminal blocks for electrical service boxes and specifically to a grounding terminal block assembly that will connect several devices to a service box. 
   BACKGROUND OF THE INVENTION 
   The National Electrical Code (NEC) now requires the grounding of data, cable TV, and phone lines. Grounding is the establishment of an electrical connection to earth through a path of sufficiently low impedance. As it relates to data, cable TV, and phone lines, the purpose of grounding is to assist in preventing the destruction of electrical components and property damage from superimposed voltage from lightning and voltage transients. Grounding the various connections to the earth also helps in reducing static charges on equipment surfaces to ensure the proper performance of sensitive electronic equipment. Grounding communications equipment to the earth reduces high voltage from lightning and keeps it from entering into the building or structure via metal cables or raceways. If the metal portions of communication equipment are not grounded in accordance with the NEC, a significant amount of the high energy from the lightning strike will be dissipated within the structure, which can result in equipment and property damage as well as the potential for electric shock. Grounding also helps establish a zero voltage reference point to ensure proper performance of sensitive communications equipment. 
   In a parent application for patent, which has been incorporated herein by reference thereto, there was provided a grounding block assembly for multiple services that included a die-cast tubular body with a plurality of threaded bores and a plurality of threaded fasteners for cooperating with the threaded bores for securing multiple electrical services to the tubular body for the purpose of grounding each of the separate electrical services. The grounding block assembly included integral legs that enabled direct attachment of the tubular body to a wall or similar structure. For those situations in which the grounding block assembly was used in conjunction with an electrical service panel or meter can, a threaded nose portion and lock nut on the tubular body enabled direct connection to the service panel or meter can. Side ports were provided in the tubular body for inspection purposes to enable rapid viewing of the integrity of grounding connections therein. The grounding block assembly provided a device for meeting the NEC&#39;s requirements for grounding all the electrical systems leading into the home including line voltage, data, cable TV, and phone lines. 
   Although the grounding block assembly of the parent patent application provided a grounding block assembly for grounding a meter can and connecting multiple services thereto, there still is a need for a device for adding grounding capability to existing grounding wires leading to meter cans and the like. In the present invention, a grounding block assembly is provided for securing onto existing grounded systems in order to provide additional grounding terminals for additional electrical systems such as data, cable TV, and phone lines. The grounding block assembly of the current invention adds an additional advantageous feature by providing a detachable cover constructed of electrically nonconductive material. The detachable insulating cover shields the grounding block and attached wiring thereby protecting the terminals and providing an attractive cover to occlude the view of the wiring and terminals. 
   SUMMARY OF THE INVENTION 
   The invention is a grounding terminal block assembly for securing to an existing ground wire to provide additional connection points for electrical systems such data, cable TV, and phone lines. The grounding terminal block assembly includes an elongated grounding bar with a plurality of threaded bores extending laterally therein. Fasteners are threaded into one or more of the threaded bores to provide connection points for ground wires from one or more electrical systems. A channel on one end of the grounding bar includes a slotted headless set screw for establishing a secure connection to an existing ground wire. Legs are provided integral with the grounding bar for providing direct connection to a wall or other structure. A detachable insulating cover is secured to the grounding bar to shield the grounding body and all wiring connections. 
   OBJECTS AND ADVANTAGES 
   Several advantages are achieved with the grounding terminal block assembly of the present invention, including:
         (1) A plurality of grounding terminals are provided for adding a number of additional connection points to an existing ground wire thereby establishing grounding for a plurality of electrical systems, including phone, data, and cable TV systems.   (2) An open channel is provided at one end of the grounding block assembly to enable rapid connection to an existing installed ground wire.   (3) A main body portion is die cast in one piece of metal alloy with superior electrical conduction properties for establishing proper ground to an existing ground wire.   (4) The grounding terminal block assembly includes integral legs for direct connection to a wall or similar structure.   (5) The grounding terminal block assembly includes a detachable cover constructed of electrically nonconductive material for shielding and protecting the grounding block and its terminals.   (6) After initial installation, the detachable cover can easily be detached in order to connect additional wiring systems to the grounding terminals.       

   These and other objects and advantages of the present invention will be better understood by reading the following description along with reference to the drawings. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of a grounding terminal block assembly including a grounding bar portion and a detachable cover according to the present invention. 
       FIG. 2  is a front perspective view of the grounding bar portion of the grounding terminal block assembly of  FIG. 1 . 
       FIG. 3  is a rear perspective view of the grounding bar of  FIG. 2 . 
       FIG. 4  is a side view of the grounding bar. 
       FIG. 5  is a front view of the grounding bar. 
       FIG. 6  is a rear view of the grounding bar. 
       FIG. 7  is a sectional view of the grounding bar taken along line  7 - 7  of  FIG. 5 . 
       FIG. 8  is a sectional view of the grounding bar taken along line  8 - 8  of  FIG. 4 . 
       FIG. 9  is a front perspective view of the detachable cover portion of the grounding terminal block assembly of  FIG. 1 . 
       FIG. 10  is a rear perspective view of the detachable cover. 
       FIG. 11  is a rear view of the detachable cover. 
       FIG. 12  is a sectional view of the cover taken along line  12 - 12  of  FIG. 11 . 
       FIG. 13  is a perspective view of a grounding terminal block assembly according to the present invention secured to a wall and with the cover secured to the grounding bar. 
       FIG. 14  is a side view of the grounding terminal block assembly secured to a wall and with the cover in sectional view secured to the grounding bar. 
   

   TABLE OF NOMENCLATURE 
   The following is a listing of part numbers used in the drawings along with a brief description: 
   Part Number Description
           20  grounding terminal block assembly     22  grounding bar     24  open channel     26  first end of grounding bar     28  detachable cover     30  ground wire     32  wall     34  threaded fastener     36  slotted headless set screw     38  cover attachment screw     40  second end of grounding bar     42  front surface of grounding bar     44  rear surface of grounding bar     46  side surface of grounding bar     48  threaded bore     50  boss     52  side bore     53  longitudinal axis through grounding bar     54  wide gap     56  inner seat     58  leg     60  front surface of leg     62  aperture in leg     64  threaded bore in boss     66  central bore in front surface of grounding bar     68  longitudinal rib     70  axis of threaded bore     72  top panel of cover     74  end panel     76  side panel     78  rear edge     80  aperture in cover     82  first side opening     84  second side opening     86  back surface     88  cover boss     90  rear surface of cover boss     92  first end leg     94  second end leg     96  intermediate leg     98  Y-shaped inner support     100  rib     102  longitudinal brace     104  lateral rib     106  mounting arrangement     107  ground wire fastening arrangement     108  threaded fastener or terminal screws     110  filet     112  ground wire   D 1  distance across wide gap   θ 1  radius of inner seat portion of open channel       

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to  FIG. 1 , the present invention comprises a grounding terminal block assembly  20  for attachment to a previously installed ground wire in order to provide several additional grounding terminals for grounding several additional electrical systems to the earth. The grounding terminal block assembly  20  includes an elongated grounding bar portion  22  with an open channel  24  at a first end  26  and a detachable cover  28 . In  FIG. 1  the grounding bar  22  has been slipped over an existing ground wire  30  by orienting the open channel  24  of the grounding bar  22  with the ground wire  30  and slipping it over the installed ground wire  30 . The grounding bar  22  is then secured to the wall  32  with threaded fasteners  34 . A slotted headless set screw  36 , which is provided as part of the grounding terminal block assembly  20 , is then tightened onto ground wire  30  thereby securing the ground wire  30  to the grounding bar  22 . Detachable cover  28  is then secured to grounding bar  22  with cover attachment screw  38 . 
   Referring to  FIGS. 2 and 3 , the elongated grounding bar  22  further includes a second end  40 , a front surface  42 , a rear surface  44 , and two side surfaces  46 . The elongated grounding bar  22  is preferably constructed of electrically conductive metals. The tubular body is preferably produced in one-piece and is die-cast of metal. A threaded bore  48  extends into the grounding bar  22  at the first end  26 . 
   With reference to  FIG. 4 , the grounding bar  22  includes a plurality of bosses  50  extending from the front surface  42 . A plurality of side bores  52  aligned along longitudinal axis  53  extend through the grounding bar  22 . The front  42 , rear  44 , and side surfaces  46  of the grounding bar  22  are flat. The open channel  24  in grounding bar  22  includes a wide gap  54  leading therein and an inner seat  56 . The wide gap  54  enables the channel  24  portion of the grounding bar  22  to be slipped over a ground wire (not shown) and the ground wire advanced until seated in inner seat  56 . 
   As shown in  FIG. 5 , two legs  58  are integral with and extend outwards from the grounding bar  22  with the legs  58  extending from opposite sides  46  of the grounding bar  22 . Each of the legs  58  includes a front surface  60  and an aperture  62  therein. The apertures  62  are at right angles with respect to the front surface  60  of the legs  58  and also with respect to the front surface  42  of the grounding bar  22 . A plurality of threaded bores  64  are provided extending into the bosses  50  and a central bore  66  is provided between the two bosses  50  extending into the front surface  42  of the grounding bar  22 . 
   Referring to  FIGS. 6-8 , the rear surface  44  of the grounding bar  22  includes a longitudinal rib  68  extending there from. The longitudinal rib  68  extends between and joins the two legs  58  thereby providing rigidity and support and bracing the legs  58 . As shown in  FIG. 7 , the plurality of threaded bores  64  extend into the grounding bar  22  and include axes  70  that are perpendicular to the front surface  42  of the grounding bar  22 . 
   With reference to  FIGS. 9 and 10 , detachable cover  28  includes a top panel  72 , end panels  74 , side panels  76  and a rear edge  78 . Top panel  72  includes an aperture  80  therein and side panels  76  include a first side opening  82  and second side opening  84 . The back surface  86  of the top panel  72  includes an integral cover boss  88  projecting therefrom, with cover boss  88  including a rear surface  90 . Side openings  82  and  84  divide the cover  28  into a first end leg  92 , a second end leg  94 , and intermediate legs  96 . 
   Referring to  FIGS. 11 and 12 , second end leg  94  is braced to said end panel  74  and said side panel  76  by Y-shaped inner supports  98  and intermediate legs  96  are braced by ribs  100  extending from the cover boss  88 . A pair of longitudinal braces  102  extends between the Y-shaped inner supports  98  and the first end leg  92  and lateral ribs  104  extend between the side panels  76  and the longitudinal braces  102  to further brace the cover  28 . 
   The grounding bar  22  of the grounding terminal block assembly  20  is preferably constructed of an electrically conductive material. Preferably the grounding bar  22  is constructed of metal with preferred metals including zinc, aluminum, brass, copper, and zinc alloys including aluminum, magnesium, and copper. Most preferably the elongated grounding bar  22  is die cast in one piece from a die-casting alloy. An especially preferred die-casting alloy is Zamak-7. 
   Reference is made to  FIG. 1  for a description of the operation of the present invention. Grounding terminal block assembly  20  includes a mounting arrangement  106  for securing the grounding block  22  to a wall  32  or similar structure. The grounding terminal block assembly  20  is an adjunct grounding block that is designed to be slipped over an existing ground wire  30  as shown in  FIG. 1 . Initially grounding terminal block assembly  20  includes slotted headless set screw  36  in a loosened state thereby providing a wide gap  54  at the entrance to open channel  24 . To operate the grounding terminal block assembly  20 , the installer removes the detachable cover  28 , aligns the open channel  28  with the ground wire  30 , and slips the grounding bar  22  under the ground wire  30  such that the ground wire  30  enters the open channel  24 . Slotted headless set screw  36  is then tightened upon ground wire  30  and the grounding bar  22  is mounted to the wall  32  using mounting arrangement  106  consisting of threaded fasteners  34  tightened through apertures  62  in legs  58  of grounding bar  22 . After the grounding bar  22  is secured to the ground wire  30  and mounted to the wall  32 , then individual ground wires (not shown) are secured to the grounding bar  22  by a ground wire fastening arrangement  107  including a plurality of electrically conductive terminal screws  108 . As the grounding bar  22  is die-cast in one piece of electrically conductive material, all ground wires connected to the grounding bar  22  by terminal screws  108  will conduct any voltage surges through the grounding bar  22  to the existing ground wire  30  and thus to earth ground thereby protecting the electrical systems connected by the terminal screws  108 . 
   After the grounding bar  22  is mounted to the wall  32  and ground wires are connected to the grounding bar  22  by the terminal screws  108 , detachable cover  28  is secured to the grounding bar  22  by cover attachment screw  38  secured into the central bore  66  in the front surface  42  of grounding bar  22 . If only a portion of grounding terminals  108  are in use and additional electrical systems are required to be grounded, detachable cover  28  may be later temporarily removed and additional ground wires connected to the grounding terminals  108 , after which the cover  28  is replaced. In case there are more electrical systems to be grounded than available terminal screws  108 , additional grounding terminal block assemblies  20  could be connected at other locations along the ground wire  30 , in the same manner as described above, to increase the number of available grounding connection points. 
   Detachable cover  28  is preferably molded in one piece of an electrically insulating material such as plastic. The plastic used to form the detachable cover  28  is preferably polypropylene, polyethylene, polyvinyl chloride (PVC), acrylonitrile-butadiene styrene (ABS), or polycarbonate. 
   With reference to  FIG. 13 , after the grounding terminal block assembly  20  is secured to a wall  32 , first and second side openings  82  and  84  provide entry ports for admitting the main ground wire  30  and ground wires for connection to the individual terminal screws (not shown). Thus, the side openings  82  and  84 , included on both sides  76  of the cover  28 , enable many different ground wire configurations and connections with the same detachable cover  28 . Filets  110  are provided around the peripheries of the side openings  82  and  84  to add rigidity and strength to the side panels  76  of the one piece molded detachable cover. 
   As shown in  FIG. 7 , it is critical that the open channel  24  of the grounding bar  22  is sized to accommodate most nominal sizes of ground wires in established grounding systems. Most preferably the radius R 1  of the inner seat  56  of open channel  24  is at least 0.165 inch and the distance D 1  across the wide gap  54  is at least 0.34 inch. 
   Referring to  FIG. 14 , when the detachable cover  28  is secured to the grounding bar  22 , the rear surface  90  of cover boss  88  contacts the front surface  42  of the grounding bar  22 . Cover boss  88  therefore positions the top panel  72  of the cover  28  above the grounding bar  22  and provides sufficient space inside the cover  28  for terminal screws  108  whether they have ground wires connected to them or not. The cover boss  88  also positions the first end leg  92 , second end leg  94 , and intermediate leg  96  flush with the wall  32 . First side opening  82  and second side opening  84  (in dashed lines) enable easy viewing of the ground wire  30  to earth and any ground wires  112  that are connected to electrical systems. 
   Having thus described the invention with reference to a preferred embodiment, it is to be understood that the invention is not so limited by the description herein but is defined as follows by the appended claims.