Patent Publication Number: US-9837730-B1

Title: Insulation piercing measurement connectors

Description:
FIELD OF THE INVENTION 
     The present invention relates to electrical cables and, more particularly, to connectors for electrical cables. 
     BACKGROUND 
     Conventional insulation piercing connectors are used to form mechanical and electrical connections between insulated cables. Typically, a conventional insulation piercing connector includes metal piercing blades with sets of teeth on either end thereof. The piercing blades are mounted in housing members (e.g., along with environmental sealing components). The housing members are clamped about insulated main and tap cables so that one set of teeth of a piercing blade engages the main cable and the other set of teeth of the piercing blade engages the tap cable. The teeth penetrate the insulation layers of the cables and make contact with the underlying conductors, thereby providing electrical continuity between the conductors through the piercing blade. Conventional insulation piercing connectors can be somewhat complex and cumbersome to install in the field. As such, a need exists for insulation piercing connectors that can be easily and quickly installed in the field without requiring special tools. 
     SUMMARY 
     According to embodiments of the invention, an insulation piercing connector for attachment to an insulated electrical cable includes a connector body, a bolt, a piercing pin, and an insulator member that electrically insulates the piercing pin from the bolt. The connector body includes a cable receiving slot that is configured to receive the insulated electrical cable therein, such as an electrical power cable. The connector body also includes a threaded bore that is in communication with the cable receiving slot. Typically, the connector body is formed from electrically insulative material and may have a generally cylindrical configuration or a generally rectangular configuration, although other configurations are possible. However, the connector body may be formed from various materials, such as metal, in some embodiments. 
     The bolt defines a longitudinal axis and includes a threaded shank, a central bore coincident with the longitudinal axis, and a head that is joined to the threaded shank by a shear-off section. The threaded shank is threadingly engaged with the threaded bore and the head is configured to be sheared off by a torque exceeding a predetermined value as the bolt is rotated in a first (e.g., clockwise) direction. The piercing pin is supported within the central bore of the bolt by the insulator member and includes opposite first and second ends. The first end is configured to pierce the insulation of an electrical cable extending through the cable receiving slot and contact the conductor under the insulation as the bolt is rotated in the first direction. In some embodiments, the threaded bore of the connector body includes a stop that limits travel of the bolt into the connector body, and thereby controls how far the piercing pin can penetrate into an electrical cable. 
     The central bore of the bolt is threaded and a sensor can be threadingly secured to the threaded bore. The sensor includes a probe that contacts the second end of the piercing pin to obtain information from the conductor, such as voltage, current, and/or thermal information, etc. In some embodiments, the sensor includes an electronic display that is configured to display information obtained from the conductor. The sensor may be removably secured to the connector. In some embodiments, when the sensor is not secured to the connector, a cap is removably secured to the central bore of the bolt and is configured to seal the central bore from exposure to the environment. 
     According to other embodiments of the present invention, an insulation piercing connector for attachment to an electrical cable includes a connector body, a bolt, and a piercing pin operably associated with the bolt. The connector body includes a cable receiving slot that is configured to receive the insulated electrical cable therein, such as an electrical power cable. The connector body also includes a threaded bore that is in communication with the cable receiving slot. Typically, the connector body is formed from electrically insulative material and may have a generally cylindrical configuration or a generally rectangular configuration, although other configurations are possible. However, the connector body may be formed from various materials, such as metal, in some embodiments. 
     The bolt defines a longitudinal axis and includes a threaded shank that is threadingly engaged with the central bore of the connector body. The bolt also includes a central bore that is coincident with the longitudinal axis. An electrically insulative bushing is disposed within the central bore of the bolt and includes a threaded bore. The piercing pin includes opposite first and second ends and a threaded intermediate portion between the first and second ends. The threaded intermediate portion is threadingly engaged with the threaded bore of the bushing. The bushing electrically insulates the piercing pin from the bolt. The first end of the piercing pin is configured to pierce the insulation of an electrical cable extending through the cable receiving slot and contact a conductor therein as the piercing pin is rotated in a first (e.g., clockwise) direction. 
     The threaded bore of the connector body includes a stop that limits travel of the bolt into the connector body. The piercing pin includes a head that is joined to the second end of the piercing pin by a shear-off section. Rotation of the piercing pin head causes the threaded shank of the bolt to threadingly engage with the threaded bore of the connector body until the bolt contacts the stop. Continued rotation of the head causes the first end of the piercing pin to pierce insulation of the electrical cable extending through the cable receiving slot. The head of the piercing pin is configured to be sheared off by a torque exceeding a predetermined value after the first end of the piercing pin contacts the conductor under the insulation. 
     The central bore of the bolt is threaded and a sensor can be threadingly secured to the threaded bore. The sensor includes a probe that contacts the second end of the piercing pin to obtain information from the conductor, such as voltage, current, and/or thermal, information, etc. In some embodiments, the sensor includes an electronic display that is configured to display information obtained from the conductor. The sensor may be removably secured to the connector. In some embodiments, when the sensor is not secured to the connector, a cap is removably secured to the central bore of the bolt and is configured to seal the central bore from exposure to the environment. 
     It is noted that aspects of the invention described with respect to one embodiment may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which form a part of the specification, illustrate some exemplary embodiments. The drawings and description together serve to fully explain the exemplary embodiments. 
         FIG. 1  is a top plan view of an insulation piercing connector for attachment to an electrical cable, according to some embodiments of the present invention. 
         FIG. 2  is a cross-sectional view of the insulation piercing connector of  FIG. 1  taken along the line  2 - 2  of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the bolt of the insulation piercing connector of  FIG. 2  illustrating the piercing pin supported within a central bore of the bolt via an insulator member, and also illustrating a sensor threadingly secured to the threaded bore of the bolt. 
         FIG. 4  is a side view of the sensor of  FIG. 3 . 
         FIG. 5  is a top plan view of the sensor of  FIG. 4  taken along line  5 - 5  of  FIG. 4  that illustrates the display. 
         FIG. 6  is a top perspective view of a connector body for an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 6A  is a top plan view of the connector body of  FIG. 6 . 
         FIG. 6B  is a cross-sectional view of the connector body of  FIG. 6A  taken along line  6 B- 6 B of  FIG. 6A . 
         FIG. 6C  is a cross-sectional view of the connector body of  FIG. 6A  taken along line  6 C- 6 C of  FIG. 6A . 
         FIG. 7  is a top perspective view of a connector body for an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 7A  is a top plan view of the connector body of  FIG. 7 . 
         FIG. 7B  is a cross-sectional view of the connector body of  FIG. 7A  taken along line  7 B- 7 B of  FIG. 7A . 
         FIG. 7C  is a cross-sectional view of the connector body of  FIG. 7A  taken along line  7 C- 7 C of  FIG. 7A . 
         FIG. 8  is a top plan view of the bolt of the insulation piercing connector of  FIG. 2  prior to being threadingly engaged with the connector body of the insulation piercing connector. 
         FIG. 8A  is a cross-sectional view of the bolt of  FIG. 8  taken along line  8 A- 8 A of  FIG. 8  and illustrating a head joined to the threaded shank of the bolt by a shear-off section. 
         FIG. 9  is a top plan view of a piercing pin that can be utilized with an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 9A  is a cross-sectional view of the piercing pin of  FIG. 9  taken along line  9 A- 9 A of  FIG. 9 . 
         FIG. 10  is a top plan view of a piercing pin that can be utilized with an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 10A  is a cross-sectional view of the piercing pin of  FIG. 10  taken along line  10 A- 10 A of  FIG. 10 . 
         FIG. 11  is a top plan view of a piercing pin that can be utilized with an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 11A  is a cross-sectional view of the piercing pin of  FIG. 11  taken along line  11 A- 11 A of  FIG. 11 . 
         FIG. 12A  is a top perspective view of an insulator member that is configured to support a piercing pin within an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 12B  is a cross-sectional view of the insulator member of  FIG. 12A  taken along line  12 B- 12 B of  FIG. 12A . 
         FIG. 13A  is a top perspective view of an insulator member that is configured to support a piercing pin within an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 13B  is a cross-sectional view of the insulator member of  FIG. 13A  taken along line  13 B- 13 B of  FIG. 13A . 
         FIG. 14A  is a top perspective view of an insulator member that is configured to support a piercing pin within an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 14B  is a cross-sectional view of the insulator member of  FIG. 14A  taken along line  14 B- 14 B of  FIG. 14A . 
         FIG. 15  is a cross-sectional view of a bolt for an insulation piercing connector, according to some embodiments of the present invention, and illustrating a piercing pin supported within the central bore of the bolt by an insulator member, and also illustrating a head joined to the threaded shank of the bolt by a shear-off section. 
         FIGS. 16 and 17  are cross-sectional views of a bolt for an insulation piercing connector, according to some embodiments of the present invention, and illustrating a piercing pin supported within the central bore of the bolt by an insulator member, and also illustrating a cap removably secured to the central bore of the bolt that seals the central bore from exposure to the environment. 
         FIG. 18  is a cross-sectional view of a bolt for an insulation piercing connector, according to some embodiments of the present invention, and illustrating a piercing pin that is utilized to threadingly engage the bolt within a connector body of the insulation piercing connector. 
         FIG. 19  is a perspective view of an insulation piercing connector, according to some embodiments of the present invention. 
         FIG. 20  is a cross-sectional view of the insulation piercing connector of  FIG. 19  taken along line  20 - 20  of  FIG. 19 . 
         FIG. 21  is a cross-sectional view of an insulation piercing connector, according to some embodiments of the present invention, and illustrating a piercing pin supported within the central bore of the bolt by a dome-type insulator member. 
         FIG. 22  is a cross-sectional view of an insulation piercing connector, according to some embodiments of the present invention, and illustrating a piercing pin supported within the central bore of the bolt by an accordion-type insulator member. 
         FIG. 23  is a cross-sectional view of an insulation piercing connector, according to some embodiments of the present invention, and illustrating a piercing pin that is utilized to threadingly engage the bolt within a connector body of the insulation piercing connector. 
         FIG. 24  is a cross-sectional view of an insulation piercing connector, according to some embodiments of the present invention, with an electrical cable positioned within the cable receiving slot of the connector body, and illustrating a piercing pin that is utilized to threadingly engage the bolt within the connector body and pierce the insulation of the electrical cable. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     It will be understood that when an element is referred to as being “coupled” or “connected” to another element, it can be directly coupled or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly coupled” or “directly connected” to another element, there are no intervening elements present. Like numbers refer to like elements throughout. As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     In addition, spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. 
     The term “about”, as used herein with respect to a value or number, means that the value or number can vary by +/− twenty percent (20%). 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Referring initially to  FIGS. 1-3 , an insulation piercing connector  10  for attachment to an electrical cable according to some embodiments of the present invention is shown therein. Exemplary electrical cables with which the connector  10  can be utilized include, but are not limited to, low voltage electrical power cables (e.g., up to about 1000V) and medium voltage electrical power cables (e.g., up to about 65 kV). However, connectors according to embodiments of the present invention may be utilized with various other types of electrical power cables, also. The illustrated connector  10  includes a connector body  20  having an electrical cable receiving slot  22  extending therethrough and a threaded bore  24  communicating with the cable receiving slot  22 . A bolt  40  is threadingly engaged with the threaded bore  24  and includes a central bore  42 . In the illustrated embodiment of  FIGS. 1-3 , the central bore  42  has a first portion  42   a  with a first diameter and a second, lower portion  42   b  that has a larger diameter than the first portion  42   a . The illustrated central bore  42  also has an upper threaded portion  42   c . A piercing pin  60  is disposed within the central bore  42  of the bolt  40 , and an insulator member  80  is disposed within the central bore  42  of the bolt that electrically insulates the piercing pin  60  from the bolt  40 . The central bore  42  in the embodiment of  FIGS. 1-3  is configured to matingly receive the various insulator member embodiments illustrated in  FIGS. 12A-12B, 13A-13B and 14A-14B . 
     Several embodiments of the connector body  20  are illustrated in  FIGS. 6, 6A-6C, 7 and 7A-7C . The connector body  20  illustrated in  FIGS. 6 and 6A-6C  has a generally cylindrical configuration, and the connector body  20  illustrated in  FIGS. 7 and 7A-7C  has a generally rectangular configuration. However, a connector body  20  can have various shapes and configurations and is not limited to a generally cylindrical or generally rectangular configuration. In each illustrated embodiment, the connector body  20  includes a cable receiving slot  22  that forms two opposing portions or wings  20   a ,  20   b . Each wing  20   a ,  20   b  has a respective arcuate threaded wall  24   a ,  24   b  formed therein as illustrated. Together, the arcuate threaded walls  24   a ,  24   b  form the threaded bore  24  of the connector body  20 . An electrical cable (e.g., EC,  FIG. 24 ) is inserted within the slot  22  between the two opposing wings  20   a ,  20   b  prior to the bolt  40  being threaded into the threaded bore  24 . One or both of the wings  20   a ,  20   b  also includes a wall portion or stop  25  at the bottom of the arcuate threaded wall  24   a ,  24   b , as illustrated. The stop  25  limits the distance that the bolt  40  can be threaded into the threaded bore  24  of the connector body  20 . The connector body  20  may be formed from various materials including electrically insulative materials, as well as various metals. 
     The illustrated connector body  20  in  FIGS. 6C and 7C  also includes a bolt over travel notch  27 . The bolt over travel notch  27  provides extra distance for the bolt  40  in FIG.  8 A to be inserted into the connector body  20 , and allows the bolt  40  to contact the conductor with the correct amount of force to be sheared at the specific torque value. Without the over travel notch  27 , the bolt  40  may bottom out in the connector body  20  before it is able to apply a required force on the conductor. The stop  25  is used for the two-stage piercing pin  160 -bolt  40  sub-assembly illustrated in  FIG. 18 . A portion of the bolt  40  will bottom out in the connector body  20  in order to break through the first shear plane P 1 , then drive the piercing pin  160  into the conductor and shear at the second shear plane P 2 , as described below. 
     Referring back to  FIGS. 1-3 , the bolt  40  includes a threaded shank  44  that is threadingly engaged within the threaded bore  24  of the connector body  20 . The bolt  40  defines a longitudinal axis A ( FIG. 2 ) and the central bore  42  of the bolt is coincident with the longitudinal axis A. In some embodiments, as illustrated in  FIGS. 15, 19 and 20 , the bolt  40  includes a head  46  that is joined to the threaded shank  44  by a shear-off section  48 . The bolt head  46  is configured to be sheared off by a torque exceeding a predetermined value as the threaded shank  44  of the bolt  40  is threadingly engaged within the threaded bore  24  of the connector body  20 . 
     The bolt head  46  of the illustrated embodiment has a hexagonal shape such that the bolt  40  can be turned with a wrench so as to threadingly secure the bolt  40  within the threaded bore  24  of the connector body  20 . In addition, the bolt head  46  of the illustrated embodiment includes a socket  50  that can be engaged by an Allen wrench or other device and such that the bolt  40  can be turned with the Allen wrench or other device so as to threadingly secure the bolt  40  within the threaded bore  24  of the connector body  20 . In the illustrated embodiment, the socket  50  has a hexagonal configuration, although other configurations are possible. 
     Referring back to  FIGS. 1-3 , the piercing pin  60  is disposed within the central bore  42  of the bolt  40 , and is held in place via the insulator member  80 . The piercing pin  60  includes opposite first and second ends  62 ,  64 , and the first end  62  has a pointed or conical shape configured to pierce the insulation (e.g., I,  FIG. 24 ) of an electrical cable (e.g., EC,  FIG. 24 ) extending through the cable receiving slot  22  and contact a conductor (e.g., C,  FIG. 24 ) beneath the insulation. Piercing pins  60  in accordance with embodiments of the present invention can have various lengths depending on the size of an electrical cable and/or conductor, the thickness of the insulation, etc. For example, in the embodiment illustrated in  FIGS. 1-3 , the piercing pin  60  can be interchangeable with other piercing pins of different lengths and/or configurations. 
     Several piercing pin configurations are illustrated in  FIGS. 10-10A and 11-11A . In the embodiment illustrated in  FIGS. 10-10A , the second end  64  of the piercing pin  60  has a tapered configuration. In the embodiment illustrated in  FIGS. 11-11A , the second end  64  of the piercing pin  60  has a generally cylindrical configuration. These tapered and cylindrical configurations are configured to match a corresponding receiving portion  84  of an insulator member  80 . For example, as illustrated in  FIG. 12B , the insulator member  80  includes a tapered receiving portion  84  that is configured to receive the tapered second end  64  of the piercing pin  60  of  FIGS. 10-10A  and hold the piercing pin  60  securely within the insulator member  80 . Similarly, as illustrated in  FIGS. 13B and 14B , each insulator member  80  includes a cylindrical receiving portion  84  that is configured to receive the cylindrical second end  64  of the piercing pin  60  of  FIGS. 11-11A  and hold the piercing pin  60  securely within the insulator member  80 . 
     The insulator member  80  is formed from insulating material, such as rubber, and can have various configurations as illustrated in  FIGS. 12A-12B, 13A-13B and 14A-14B . For example, in  FIGS. 12A-12B , the insulator member  80  includes a body  82  having opposite first and second cylindrical end portions  82   a ,  82   b  separated by a medial cylindrical portion  82   c . The first end portion  82   a  is configured to be inserted within the first portion  42   a  of the central bore  42  of the bolt  40  illustrated in  FIGS. 1-3 . The medial portion  82   c  is configured to inserted within the second portion  42   b  of the central bore  42  of the bolt  40  illustrated in  FIGS. 1-3 . The second end portion  82   b  extends outwardly from the lower end  40   b  of the bolt  40  and is configured to engage an electrical cable extending through the slot  22  of the connector body  20  when the second end  64  of the piercing pin  60  has penetrated the insulation of the electrical cable. As illustrated the second end portion  82   b  of the insulator member  80  has a larger diameter than the other portions  82   a ,  82   c  of the insulator member  80  and is configured to extend across substantially the entire width of the slot  22  and engage the respective opposing wings  20   a ,  20   b  of the connector body  20 . The medial portion  82   c  of the insulator member of  FIGS. 12A-12B  contains a tapered receiving portion  84  that is configured to receive the tapered second end  64  of the piercing pin  60  of  FIGS. 10-10A . 
     In  FIGS. 13A-13B , the insulator member  80  includes a body  82  having a first cylindrical end portion  82   a  and an opposite second end portion  82   b  separated by a cylindrical medial portion  82   c . The first end portion  82   a  is configured to inserted within the first portion  42   a  of the central bore  42  of the bolt  40  illustrated in  FIGS. 1-3 . The medial portion  82   c  is configured to inserted within the second portion  42   b  of the central bore  42  of the bolt  40  illustrated in  FIGS. 1-3 . The second end portion  82   b  extends outwardly from the lower end  40   b  of the bolt  40  and has a rounded or dome configuration, as illustrated. The second end portion  82   b  is configured to engage an electrical cable extending through the slot  22  of the connector body  20  when the second end  64  of the piercing pin  60  has penetrated the insulation of the electrical cable. As illustrated the second end portion  82   b  of the insulator member  80  has a larger diameter than the other portions  82   a ,  82   c  of the insulator member  80  and is configured to extend across substantially the entire width of the slot  22  and engage the respective opposing wings  20   a ,  20   b  of the connector body, as illustrated in  FIG. 2 . The medial portion  82   c  of the insulator member of  FIGS. 13A-13B  contains a cylindrical receiving portion  84  that is configured to receive the cylindrical second end  64  of the piercing pin  60  of  FIGS. 11-11A . 
     In  FIGS. 14A-14B , the insulator member  80  includes a body  82  having a first cylindrical end portion  82   a  and an opposite second end portion  82   b  separated by a cylindrical medial portion  82   c . The first end portion  82   a  is configured to inserted within the first portion  42   a  of the central bore  42  of the bolt  40  illustrated in  FIGS. 1-3 . The medial portion  82   c  is configured to inserted within the second portion  42   b  of the central bore  42  of the bolt  40  illustrated in  FIGS. 1-3 . The second end portion  82   b  extends outwardly from the lower end  40   b  of the bolt  40  and has an accordion configuration, as illustrated. The second end portion  82   b  is configured to engage an electrical cable extending through the slot  22  of the connector body  20  when the second end  64  of the piercing pin  60  has penetrated the insulation of the electrical cable. The medial portion  82   c  of the insulator member of  FIGS. 14A-14B  contains a cylindrical receiving portion  84  that is configured to receive the cylindrical second end  64  of the piercing pin  60  of  FIGS. 11-11A . 
     A sealant, such as a sealant gel, may be utilized at the second end portions  82   b  of the insulator members  80  of  FIGS. 12A-12B, 13A-13B and 14A-14B  to further insulate the piercing pin and the pierced portion of the electrical cable from the environment. For example, the second end portions  82   b  of the insulator members  80  may contain a sealant gel that the piercing pin extends through as it pierces the insulation of an electrical cable within the slot  22  of the connector body  20 . Various types of sealant gels may be utilized including, but not limited to, silicone gels, polyurethane gels, gels based on styrene-ethylene butylenestyrene (SEBS) or styrene-ethylene propylene-styrene (SEPS), EPDM rubber-based gels, gels based on anhydride-containing polymers, and the like. The sealant gel may include a variety of additives, including stabilizers and antioxidants such as hindered phenols (e.g., Irganox™ 1076, commercially available from Ciba-Geigy Corp. of Tarrytown, N.Y.), phosphites (e.g., Irgafos™ 168, commercially available from Ciba-Geigy Corp. of Tarrytown, N.Y.), metal deactivators (e.g., Irganox™ D1024 from Ciba-Geigy Corp. of Tarrytown, N.Y.), and sulfides (e.g., Cyanox LTDP, commercially available from American Cyanamid Co. of Wayne, N.J.), light stabilizers (e.g., Cyasorb UV-531, commercially available from American Cyanamid Co. of Wayne, N.J.), and flame retardants such as halogenated paraffins (e.g., Bromoklor 50, commercially available from Ferro Corp. of Hammond, Ind.) and/or phosphorous containing organic compounds (e.g., Fyrol PCF and Phosflex 390, both commercially available from Akzo Nobel Chemicals Inc. of Dobbs Ferry, N.Y.) and acid scavengers (e.g., DHT-4A, commercially available from Kyowa Chemical Industry Co. Ltd through Mitsui &amp; Co. of Cleveland, Ohio, and hydrotalcite). Other suitable additives include colorants, biocides, tackifiers and the like described in “Additives for Plastics, Edition 1” published by D.A.T.A., Inc. and The International Plastics Selector, Inc., San Diego, Calif. 
     Referring back to  FIGS. 1-5 , the illustrated insulation piercing connector  10  includes a sensor  90  that is attached to the connector body  20  after the bolt  40  has been threadingly secured within the threaded bore  24  of the connector body  20 , and after piercing pin piercing end  62  has pierced the insulation of an electrical cable and contacted a conductor within the electrical cable, as described herein. The illustrated sensor  90  includes a threaded portion  92  having opposite first and second end portions  92   a ,  92   b . A probe  94  extends outwardly from the second end portion  92   b  and is configured to contact and make electrical contact with the free end surface  66  of the piercing pin second end  64  when the threaded portion  92  is threadingly secured within the threaded portion  42   c  of the central bore  42  of the bolt  40 . A head portion  96  is located at the first end portion  92   a  of the threaded portion  92  and is configured to engage the upper surface  40   a  of the bolt, as illustrated in  FIGS. 2-3 . A housing  98  is attached to the head portion  96  and includes a display  100  visible through an upper surface  98   a  thereof. The housing  98  also contains one or more sensors for detecting information from an electrical conductor such as, but not limited to, voltage information, current information, thermal information, etc. These sensors detect information from the conductor of an electrical cable via the piercing pin  60  which is in contact with the conductor. In addition, the housing  98  may contain a power supply such as a battery, as well as a wireless transmitter for transmitting sensor data to a remote device. The display  100  may be configured to display sensor information and may serve as a status indicator for the electrical cable. 
     In some embodiments, the sensor  90  is configured to be threadingly secured to a connector  10  by hand. In other embodiments, a wrench may be used to secure and remove the sensor  90  to the connector  10 . As illustrated in  FIGS. 21 and 22 , in some embodiments, a cap  110  may be removably secured to the central bore  42  of the bolt  40  after the head  46  is sheared off. In other embodiments, as illustrated in  FIGS. 16 and 17 , a removable cap  110  may be pre-assembled with the bolt subassembly. As such, when the head  46  is sheared off, the removable cap  110  is already in place and removably secured to the central bore  42  of the bolt  40 . The cap  110  is configured to seal the central bore  42 , and thus the piercing pin  60 , from exposure to the environment. To obtain information from an electrical cable positioned within the connector body slot  22  and to which the connector  10  is attached, the cap  110  is removed and a sensor  90  is threadingly secured within the threaded portion  42   c  of the central bore  42 , as described above. Upon removal of the sensor  90 , the cap  110  may again be secured to the central bore  42 . 
     Referring now to  FIGS. 9, 9A, 18, 23 and 24 , a connector  10  for an electrical cable having a piercing pin  160  according to other embodiments of the present invention will be described. The illustrated piercing pin  160 , when rotated via a wrench, is configured to threadingly rotate the bolt  40  into the connector body  20  until the bolt reaches the stop  25  and then continue on rotating so that the piercing end  162  pierces the insulation I ( FIG. 24 ) of an electrical cable EC ( FIG. 24 ) extending through the cable receiving slot  22  of the connector body  20  ( FIGS. 23, 24 ). As illustrated in  FIGS. 9-9A , the piercing pin  160  includes a piercing end  162 , a threaded intermediate portion  164 , a radially enlarged portion  166 , a shear-off portion  168 , and a head portion  170 . The piercing end  162  has a pointed or conical shape configured to pierce the insulation I of the electrical cable EC extending through the cable receiving slot  22  of the connector body  20  ( FIGS. 23, 24 ) and contact the conductor C ( FIG. 24 ) beneath the insulation I. The head portion  170  in the illustrated embodiment has a hexagonal shape that is configured to be engaged by a wrench or other tool so that the piercing pin can be rotated via the wrench or other tool. 
     As shown in  FIGS. 18, 23 and 24 , a bushing  180  having a threaded bore  182  is disposed within the central bore  42  of the bolt  40 . The threaded intermediate portion  164  of the piercing pin  160  is threadingly engaged with the threaded bore  182  of the bushing  180 . Frictional engagement of the threaded intermediate portion  164  with the threaded bore  182  of the bushing  180  is sufficient to cause the bushing  180  to rotate the bolt  40  as the piercing pin  160  is being rotated until the bolt reaches the stop(s)  25  in the connector body. Once the bolt  40  reaches the stop(s)  25 , continued rotation of the piercing pin  160  within the threaded bore  182  of the bushing  180  causes the piercing end  162  to continue its travel so that it can pierce the insulation I ( FIG. 24 ) of the electrical cable EC ( FIG. 24 ) extending through the cable receiving slot  22  of the connector body  20  ( FIGS. 23, 24 ). The shear-off portion  168  including the head portion  170  is configured to be sheared off by a torque exceeding a predetermined value after the piercing end  162  makes contact with the conductor C of the electrical cable EC. When the shear-off portion  168  is sheared off, a surface  166   a  of the radially enlarged portion  166  is exposed. This surface  166   a  is configured to be contacted by the probe  94  of a sensor  90 , as described above. 
     The illustrated piercing pin  160  includes first and second shear planes P 1 , P 2  ( FIG. 9A ). The piercing pin  160  will be pre-assembled into a sub-assembly, as shown in  FIG. 18 . The illustrated sub-assembly of  FIG. 18  will then be installed into a connector body  20  where it will bottom out on the stop  25  in the connector body  20 . Once this happens, the first shear plane P 1  will then be sheared, allowing the piercing pin  160  to begin driving into the electrical cable insulation I ( FIG. 24 ) using threaded bore  182 . Once the piercing pin  160  is driven into the conductor C ( FIG. 24 ) and hits a certain torque value, the second shear plane P 2  will then shear off the head portion  170  which can then be either capped or a sensor can then be mounted for measurement readings. 
     Insulation piercing connectors according to embodiments of the present invention are advantageous over conventional connectors because the robust wrap-around design facilitates easy installation on existing power lines and without requiring special installation tools. Moreover, no cable stripping or cutting is required. Furthermore, insulation piercing connectors according to embodiments of the present invention facilitate the use of sensors for monitoring electrical distribution systems. 
     The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the invention.