Patent Publication Number: US-7905735-B2

Title: Push-then-pull operation of a separable connector system

Description:
RELATED PATENT APPLICATIONS 
     This patent application is related to co-pending U.S. patent application Ser. No. 12/072,333, entitled “Separable Connector with Interface Undercut,” filed Feb. 25, 2008; U.S. patent application Ser. No. 12/072,498, entitled “Separable Connector With Reduced Surface Contact,” filed Feb. 25, 2008; U.S. patent application Ser. No. 12/072,164, entitled “Dual Interface Separable Insulated Connector With Overmolded Faraday Cage,” filed Feb. 25, 2008; and U.S. patent application Ser. No. 12/072,193, entitled “Method Of Manufacturing A Dual Interface Separable Insulated Connector With Overmolded Faraday Cage,” filed Feb. 25, 2008. The complete disclosure of each of the foregoing related applications is hereby fully incorporated herein by reference. 
     TECHNICAL FIELD 
     The invention relates generally to separable connector systems for electric power systems and more particularly to easier decoupling of separable connector systems. 
     BACKGROUND 
     In a typical power distribution network, substations deliver electrical power to consumers via interconnected cables and electrical apparatuses. The cables terminate on bushings passing through walls of metal encased equipment, such as capacitors, transformers, and switchgear. Increasingly, this equipment is “dead front,” meaning that the equipment is configured such that an operator cannot make contact with any live electrical parts. Dead front systems have proven to be safer than “live front” systems, with comparable reliability and low failure rates. 
     Various safety codes and operating procedures for underground power systems require a visible disconnect between each cable and electrical apparatus to safely perform routine maintenance work, such as line energization checks, grounding, fault location, and hi-potting. A conventional approach to meeting this requirement for a dead front electrical apparatus is to provide a “separable connector system” including a first connector assembly connected to the apparatus and a second connector assembly connected to an electric cable. The second connector assembly is selectively positionable with respect to the first connector assembly. An operator can engage and disengage the connector assemblies to achieve electrical connection or disconnection between the apparatus and the cable. 
     Generally, one of the connector assemblies includes a female connector, and the other of the connector assemblies includes a corresponding male connector. In some cases, each of the connector assemblies can include two connectors. For example, one of the connector assemblies can include ganged, substantially parallel female connectors, and the other of the connector assemblies can include substantially parallel male connectors that correspond to and are aligned with the female connectors. 
     During a typical electrical connection operation, an operator slides the female connector(s) over the corresponding male connector(s). To assist with this operation, the operator generally coats the connectors with a lubricant, such as silicone. Over an extended period of time, the lubricant hardens, bonding the connectors together. This bonding makes it difficult to separate the connectors in an electrical disconnection operation. The greater the surface area of the connectors, the more difficult the connection is to break. This problem is greatly exacerbated when the separable connector system includes multiple connector pairs that must be separated simultaneously. 
     Conventionally, operators have attempted to overcome this problem by twisting one of the connector assemblies with a liveline tool prior to separating the connectors. The twisting operation can shear interface adhesion between the connectors, allowing the operator to more easily separate the connectors. There are many drawbacks to this approach. For example, the twisting operation may deform the connector assemblies by loosening and unthreading current carrying joints and/or twisting and bending an operating eye of the connector assemblies. This deformation of the connector assemblies can render the connector assemblies ineffective and/or unsafe. In addition, the ergonomics of the twisting operation may result in immediate and long term (i.e., repetitive motion) injury to the operator. Moreover, connector assemblies with multiple, substantially parallel connectors cannot be twisted to break interface adhesion. 
     Therefore, a need exists in the art for a system and method for safely and easily separating connector assemblies of a separable connector system. In particular, a need exists in the art for a system and method for safely and easily reducing or shearing interface adhesion between connectors of a separable connector system. In addition, a need exists in the art for a system and method for reducing or shearing interface adhesion between connectors of multiple substantially parallel connector pairs of a separable connector system. 
     SUMMARY 
     The invention provides systems and methods for separating connector assemblies of a separable connector system. The separable connector assemblies include one or more pairs of connectors configured to engage and disengage one another in electrical connection and disconnection operations, respectively. For example, an operator can selectively engage and disengage the connectors to make or break an energized connection in a power distribution network. 
     In one exemplary aspect of the invention, a first connector assembly is connected to a dead front or live front electrical apparatus, such as a capacitor, transformer, switchgear, or other electrical apparatus. A second connector assembly is connected to a power distribution network via a cable. Joining the connectors of the first and second connector assemblies together closes a circuit in the power distribution network. Similarly, separating the connectors opens the circuit. 
     For each pair of connectors, a first of the connectors can include a housing disposed substantially about a recess from which a probe extends. For example, the probe can include a conductive material configured to engage a corresponding conductive contact element of a second of the pair of connectors. The second connector can include a tubular housing disposed substantially about the conductive contact element and at least a portion of a tubular member, such as a piston holder, coupled to the conductive contact element. A nose piece can be secured to an end of the tubular housing, proximate a “nose end” of the second connector. The nose piece can be configured to be disposed within the recess of the first connector when the connectors are connected. An outer shoulder of the second connector can be coupled to the tubular housing. 
     In one exemplary aspect of the invention, an operator can separate the connectors by pushing the connectors together and then pulling the connectors apart. Pushing the connectors together can shear interface adhesion between the connectors, making it easier for the operator to pull the connectors apart. It also can provide a “running start” for overcoming a latching force between the connectors when pulling the connectors apart. For example, relative movement between the connectors during the push portion of this “push-then-pull” operation can be about 0.1 inches to more than 1.0 inches or between about 0.2 inches and 1.0 inches. 
     The connectors can include clearance regions sized and configured to accommodate this relative movement. For example, the connectors can include a “nose clearance” region sized and configured to accommodate relative movement of the nose end of the second connector and the recess of the first connector during a push-then-pull operation of the first and second connectors. The connectors also may include a “shoulder clearance” region sized and configured to accommodate relative movement of the shoulder of the second connector and the housing of the first connector during the push-then-pull operation. In addition, the connectors may include a “probe clearance” region sized and configured to accommodate relative movement of the probe of the first connector and the tubular member of the second connector during the push-then-pull operation. 
     In another exemplary aspect of the invention, the connectors can include a latching mechanism for securing the connectors together when they are in a connected operating position. For example, one of the connectors can include a groove, and the other of the connectors can include a latching element configured to engage the groove when the connectors are in the connected operating position. The latching element can include a locking ring, a projection of a finger contact element, such as a finger of the conductive contact element of the second connector, or another securing element apparent to a person of ordinary skill in the art having the benefit of the present disclosure. Similar to the clearance regions described above, the connectors can include a clearance region sized and configured to accommodate relative movement of the groove and the latching element during a push-then-pull operation to disconnect the connectors. 
     In yet another exemplary aspect of the invention, the nose end of the second connector can include an undercut segment configured not to engage an interior surface of the housing of the first connector when the connectors are engaged. For example, the housing can include a semi-conductive material extending along an interior portion of an inner surface of the housing. Other (non-undercut) segments of the second connector may engage the inner surface of the housing when the connectors are engaged. For example, the undercut segment can be disposed between two “interface segments” configured to engage the interior surface of the first connector when the connectors are engaged. Limiting the surface area of the nose end that interfaces with the interior surface of the other connector reduces surface adhesion and a pressure drop when separating the connectors, making separation easier to perform. For example, the undercut segment can be disposed within the nose piece of the second connector. 
     These and other aspects, objects, features, and advantages of the invention will become apparent to a person having ordinary skill in the art upon consideration of the following detailed description of illustrated exemplary embodiments, which include the best mode of carrying out the invention as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a longitudinal cross-sectional view of a separable connector system, according to certain exemplary embodiments. 
         FIG. 2  is a longitudinal cross-sectional view of a separable connector system, according to certain alternative exemplary embodiments. 
         FIG. 3  is a longitudinal cross-sectional view of the separable connector system of  FIG. 2  in an electrically connected operating position, according to certain exemplary embodiments. 
         FIG. 4  is a longitudinal cross-sectional view of the separable connector system of  FIG. 2  in a pushed-in position, according to certain exemplary embodiments. 
         FIG. 5  is a longitudinal cross-sectional view of a separable connector system, according to certain additional alternative exemplary embodiments. 
         FIG. 6  is a longitudinal cross-sectional view of a separable male connector, according to certain additional alternative exemplary embodiments. 
         FIG. 7  is a partially exploded isometric view of ganged separable female connectors and separable male connectors of  FIG. 6  connected to an electrical apparatus. 
         FIG. 8  is a longitudinal cross-sectional view of a separable male connector, according to certain additional alternative exemplary embodiments. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The invention is directed to systems and methods for safely and easily separating connector assemblies of a separable connector system. In particular, the invention is directed to systems and methods for safely and easily reducing or shearing interface adhesion between connectors of a separable connector system using a push-then-pull operation or a reducing surface contact between the connectors. The separable connector assembly includes one or more pairs of separable connectors configured to engage one another in an electrical connection operation and to disengage one another in an electrical disconnection operation. An operator can disengage the connectors during the electrical disconnection operation by pushing the connectors together and then pulling the connectors apart. Pushing the connectors together shears interface adhesion between the connectors, making it easier for the operator to pull the connectors apart. 
     Turning now to the drawings, in which like numerals indicate like elements throughout the figures, exemplary embodiments of the invention are described in detail. 
       FIG. 1  is a longitudinal cross-sectional view of a separable connector system  100 , according to certain exemplary embodiments. The system  100  includes a female connector  102  and a male connector  104  configured to be selectively engaged and disengaged to make or break an energized connection in a power distribution network. For example, the male connector  104  can be a bushing insert or connector connected to a live front or dead front electrical apparatus (not shown), such as a capacitor, transformer, switchgear, or other electrical apparatus. The female connector  102  can be an elbow connector or other shaped device electrically connected to the power distribution network via a cable (not shown). In certain alternative exemplary embodiments, the female connector  102  can be connected to the electrical apparatus, and the male connector  104  can be connected to the cable. 
     The female connector  102  includes an elastomeric housing  110  comprising an insulative material, such as ethylene-propylene-dienemonomoer (“EPDM”) rubber. A conductive shield layer  112  connected to electrical ground extends along an outer surface of the housing  110 . A semi-conductive material  190  extends along an interior portion of an inner surface of the housing  110 , substantially about a portion of a cup shaped recess  118  and conductor contact  116  of the female connector  102 . For example, the semi-conductive material  190  can included molded peroxide-cured EPDM configured to control electrical stress. In certain exemplary embodiments, the semi-conductive material  190  can act as a “faraday cage” of the female connector  102 . 
     One end  114   a  of a male contact element or probe  114  extends from the conductor contact  116  into the cup shaped recess  118 . The probe  114  comprises a conductive material, such as copper. The probe  114  also comprises an arc follower  120  extending from an opposite end  114   b  thereof. The arc follower  120  includes a rod-shaped member of ablative material. For example, the ablative material can include acetal co-polymer resin loaded with finely divided melamine. In certain exemplary embodiments, the ablative material may be injection molded on an epoxy bonded glass fiber reinforcing pin (not shown) within the probe  114 . A recess  124  is provided at the junction between the probe  114  and the arc follower  120 . An aperture  126  is provided through the end  114   b  of the probe  114  for assembly purposes. 
     The male connector  104  includes a semi-conductive shield  130  disposed at least partially about an elongated insulated body  136 . The insulated body  136  includes elastomeric insulating material, such as molded peroxide-cured EPDM. A conductive shield housing  191  extends within the insulated body  136 , substantially about a contact assembly  195 . A non-conductive nose piece  134  is secured to an end of the shield housing  191 , proximate a “nose end”  194  of the male connector  104 . The elastomeric insulating material of the insulated body  136  surrounds and bonds to an outer surface of the shield housing  191  and to a portion of the nose piece  134 . 
     The contact assembly  195  includes a female contact  138  with deflectable fingers  140 . The deflectable fingers  140  are configured to at least partially receive the arc follower  120  of the female connector  102 . The contact assembly  195  also includes an arc interrupter  142  disposed proximate the deflectable fingers  140 . The contact assembly  195  is disposed within a contact tube  196 . 
     The female and male connectors  102 ,  104  are operable or matable during “loadmake,” “loadbreak,” and “fault closure” conditions. Loadmake conditions occur when one of the contacts  114 ,  138  is energized and the other of the contacts  114 ,  138  is engaged with a normal load. An arc of moderate intensity is struck between the contacts  114 ,  138  as they approach one another and until joinder of the contacts  114 ,  138 . 
     Loadbreak conditions occur when mated male and female contacts  114 ,  138  are separated when energized and supplying power to a normal load. Moderate intensity arcing occurs between the contacts  114 ,  138  from the point of separation thereof until they are somewhat removed from one another. Fault closure conditions occur when the male and female contacts  114 ,  138  are mated with one of the contacts being energized and the other of the contacts being engaged with a load having a fault, such as a short circuit condition. In fault closure conditions, substantial arcing occurs between the contacts  114 ,  138  as they approach one another and until they are joined in mechanical and electrical engagement. 
     In accordance with known connectors, the arc interrupter  142  of the male connector  104  may generate arc-quenching gas for accelerating the engagement of the contacts  114 ,  138 . For example, the arc-quenching gas may cause a piston  192  of the male connector  104  to accelerate the female contact  138  in the direction of the male contact  114  as the connectors  102 ,  104  are engaged. Accelerating the engagement of the contacts  114 ,  138  can minimize arcing time and hazardous conditions during loadmake and fault closure conditions. In certain exemplary embodiments, the piston  192  is disposed within the shield housing  191 , between the female contact  138  and a piston holder  193 . For example, the piston holder  193  can include a tubular, conductive material, such as copper, extending from an end  138   a  of the female contact  138  to a rear end  198  of the elongated body  136 . 
     The arc interrupter  142  is sized and dimensioned to receive the arc follower  120  of the female connector  102 . In certain exemplary embodiments, the arc interrupter  142  can generate arc-quenching gas to extinguish arcing when the contacts  114 ,  138  are separated. Similar to the acceleration of the contact engagement during loadmake and fault closure conditions, generation of the arc-quenching gas can minimize arcing time and hazardous conditions during loadbreak conditions. 
     In certain exemplary embodiments, the female connector  102  includes a locking ring  150  protruding from the cup shaped recess  118 , substantially about the end  114   a  of the probe  114 . A locking groove  151  in the nose piece  134  of the male connector  104  is configured to receive the locking ring  150  when the male and female connectors  102 ,  104  are engaged. An interference fit or “latching force” between the locking groove  151  and the locking ring  150  can securely mate the male and female connectors  102 ,  104  when the connectors  102 ,  104  are electrically connected. An operator must overcome this latching force when separating the male and female connectors  102 ,  104  during an electrical disconnection operation. A person of ordinary skill in the art having the benefit of the present disclosure will recognize that many other suitable means exist for securing the connectors  102 ,  104 . For example, a “barb and groove” latch, described below with reference to  FIG. 2 , may be used to secure the connectors  102 ,  104 . 
     To assist with an electrical connection operation, an operator can coat a portion of the female connector  102  and/or a portion of the male connector  104  with a lubricant, such as silicone. Over an extended period of time, the lubricant may harden, bonding the connectors  102 ,  104  together. This bonding can make it difficult to separate the connectors  102 ,  104  in an electrical disconnection operation. The operator must overcome both the latching force of the locking ring  150  and locking groove  151  and interface adhesion between the connectors  102 ,  104  caused by the hardened lubricant to separate the connectors  102 ,  104 . 
     The separable connector system  100  of  FIG. 1  allows the operator to safely and easily overcome the latching force and interface adhesion using a push-then-pull operation. Instead of pulling the connectors  102 ,  104  apart from their ordinary engaged operating position, as with traditional connector systems, the operator can push the connectors  102 ,  104  further together prior to pulling the connectors  102 ,  104  apart. Pushing the connectors  102 ,  104  together can shear the interface adhesion between the connectors  102 ,  104 , making it easier for the operator to pull the connectors  102 ,  104  apart. It also can provide a “running start” for overcoming the latching force when pulling the connectors  102 ,  104  apart. 
     Each of the connectors  102 ,  104  is sized and configured to accommodate the push-then-pull operation. First, the cup-shaped recess  118  of the female connector  102  includes a “nose clearance” region  152  sized and configured to accommodate relative movement of the nose end  194  of the male connector  104  and the cup-shaped recess  118  during the push-then-pull operation. For example, the nose end  194  and/or the cup-shaped recess  118  can move along an axis of the probe  114 , with the nose end  194  being at least partially disposed within the nose clearance region  152 . In certain exemplary embodiments, an edge  194   a  of the nose end  194  can abut an end  153  of the cup shaped recess  118 , within the nose clearance region  152 , when the push portion of the push-then-pull operation is completed, i.e., when the connectors  102 ,  104  are completely pushed together. For example, an edge of the contact tube  196  and/or an edge of the nose piece  134 , proximate the nose end  194  of male connector  104 , can abut the end  153  of the cup shaped recess  118  when the push portion of the push-then-pull operation is completed. 
     Second, the housing  110  of the female connector  102  includes a “shoulder clearance” region  154  sized and configured to accommodate relative movement of a shoulder  155  of the male connector  104  and the housing  110  of the female connector  102  during the push-then-pull operation. For example, the shoulder  155  and/or the housing  110  can move along an axis parallel to the axis of the probe  114 , with the shoulder  155  being at least partially disposed within the shoulder clearance region  154 . In certain exemplary embodiments, an end  155   a  of the shoulder  155  can abut an end  156  of the housing  110 , within the shoulder clearance region  154 , when the push portion of the push-then-pull operation is completed. 
     Third, the piston holder  193  of the male connector  104  includes a “probe clearance” region  157  sized and configured to accommodate relative movement of the piston holder  193  and the probe  114  of the female connector  102  during the push-then-pull operation. For example, the probe  114  and/or piston holder  193  can move along an axis of the probe  114 , with the probe  114  being at least partially disposed within the probe clearance region  157 . In certain exemplary embodiments, an end  158  of the arc follower  120  of the probe  114  can abut an end  193   a  of the piston holder  193 , within the probe clearance region  157 , when the push portion of the push-then-pull operation is completed. 
     Fourth, the locking groove  151  in the nose piece  134  of the male connector  104  includes a “latching clearance” region  159  sized and configured to accommodate relative movement of the locking ring  150  of the female connector  102  and the locking groove  151  during the push-then-pull operation. For example, the locking ring  150  and/or locking groove  151  can move along an axis parallel to the axis of the probe  114 , with the locking ring  150  being at least partially disposed within the latching clearance region  159 . In certain exemplary embodiments, an end  160  of the locking ring  150  can abut an end  161  of the latching groove  151 , within the latching clearance region  159 , when the push portion of the push-then-pull operation is completed. In certain alternative exemplary embodiments (not illustrated in  FIG. 1 ), the male connector  104  can include a locking ring  150 , and the female connector  102  can include a locking groove  151  and latching clearance region  159 . 
     A person of ordinary skill in the art having the benefit of the present disclosure will recognize that the clearances described herein are merely exemplary in nature and that other suitable clearances and other suitable means exist for accommodating relative movement between the connectors during a push-then-pull operation. 
     The relative movement of the connectors  102 ,  104  during the push-then-pull operation can vary depending on the sizes of the connectors  102 ,  104  and the strength of the interface adhesion to be sheared when separating the connectors  102 ,  104 . For example, in certain exemplary embodiments, the relative movement of the connectors  102 ,  104  during the push portion of the push-then-pull operation can be on the order of about 0.1 inches to about 1.0 or more inches. One or both of the connectors  102 ,  104  can move during the push-then-pull operation. For example, one of the connectors  102 ,  104  can remain stationary while the other of the connectors  102 ,  104  moves towards and away from the stationary connector  102 ,  104 . Alternatively, both connectors  102 ,  104  can move towards and away from one another. 
       FIG. 2  is a longitudinal cross-sectional view of a separable connector system  200 , according to certain alternative exemplary embodiments. The system  200  includes a female connector  221  and a male connector  231  configured to be selectively engaged and disengaged to make or break an energized connection in a power distribution network. The female and male connectors  221 ,  231  are substantially similar to the female and male connectors  102 ,  104 , respectively, of the system  100  of  FIG. 1 , except that the connectors  221 ,  231  of  FIG. 2  include a different probe  201  and latching mechanism than the probe and (ring and groove) latching mechanism of the connectors  102 ,  104  of  FIG. 1 . 
     The probe  201  includes a substantially cylindrical member with a recessed tip  203  near a first end of the probe  201 . For example, the cylindrical member can include a rod or a tube. In a circuit closing operation, the recessed tip  203  penetrates into and connects with finger contacts  211  of the male connector  231 . 
     The probe  201  includes a recessed area  205 , which provides a contact point for interlocking the probe  201  with the finger contacts  211  when the male and female connectors  221 ,  231  are connected. A first end of each finger contact  211  includes a projection  213  configured to provide a contact point for each finger contact  211  to interlock with the recessed area  205 . For example, as the probe  201  is inserted into the finger contacts  211  during an electrical connection operation, the probe  201  can slide into the finger contacts  211  by riding on the projection  213  of each finger contact  211 . 
     Each projection  213  includes a rounded front face and a backside including a ridge angled steeper than the rounded front face. The ridge of the projection  213  is sloped closer to perpendicular to an axis of motion of the probe  201  than the rounded front face of the projection  213 . The rounded front face of the projection  213  allows the probe  201  to slide into the finger contacts  211  with minimal resistance and reduced friction. The ridge on the backside of the projection  213  latches the probe  201  into the finger contacts  211 . Upon seating of the probe  201  within the finger contacts  211 , the ridge of the projection  213  locks into the recessed area  205 . The steeper angle of the ridge causes a greater force to be required to remove the probe  201  from the finger contacts  211  than to insert the probe  201  into the finger contacts  211 . 
     When the probe  201  is inserted into the finger contacts  211 , the finger contacts  211  expand outwardly to accommodate the probe  201 . In certain exemplary embodiments, an external surface of each finger contact  211  includes at least one recessed groove  219  configured to house at least one expandable retention spring  215 . The expandable retention springs  215  are configured to restrict flexibility of the finger contacts  211 , thereby increasing contact pressure of each finger contact  211 . For example, each retention spring  215  can include a flexible, substantially circular member configured to expand or contract based on an applied force. 
     As with the separable connector system  100  of  FIG. 1 , the separable connector system  200  of  FIG. 2  allows the operator to safely and easily separate the connectors  221 ,  231  using a push-then-pull operation. Each of the connectors  221 ,  231  is sized and configured to accommodate the push-then-pull operation. First, as with the separable connector system  100  of  FIG. 1 , a cup-shaped recess  218  of the female connector  221  includes a “nose clearance” region  252  sized and configured to accommodate relative movement of a nose end  234  of the male connector  231  and the cup-shaped recess  218  during the push-then-pull operation. For example, the nose end  234  and/or the cup-shaped recess  218  can move along an axis of the probe  201 , with the nose end  234  being at least partially disposed within the nose clearance region  252 . In certain exemplary embodiments, an edge  234   a  of the nose end  234  can abut an end  253  of the cup shaped recess  218 , within the nose clearance region  252 , when the push portion of the push-then-pull operation is completed, i.e., when the connectors  221 ,  231  are completely pushed together. 
     Second, a housing  223  of the female connector  221  includes a “shoulder clearance” region  254  sized and configured to accommodate relative movement of a shoulder  255  of the male connector  231  and the housing  223  of the female connector  221  during the push-then-pull operation. For example, the shoulder  255  and/or the housing  223  can move along an axis parallel to the axis of the probe  201 , with the shoulder  255  being at least partially disposed within the shoulder clearance region  254 . In certain exemplary embodiments, an end  255   a  of the shoulder  255  can abut an end  256  of the housing  223 , within the shoulder clearance region  254 , when the push portion of the push-then-pull operation is completed. 
     Third, a piston holder  232  of the male connector  231  includes a “probe clearance” region  257  sized and configured to accommodate relative movement of the piston holder  232  and the probe  201  of the female connector  221  during the push-then-pull operation. For example, the probe  201  and/or piston holder  232  can move along an axis of the probe  201 , with the probe  201  being at least partially disposed within the probe clearance region  257 . In certain exemplary embodiments, an end  258  of the probe  201  can abut an end  232   a  of the piston holder  232 , within the probe clearance region  257 , when the push portion of the push-then-pull operation is completed. 
     Fourth, the recessed area  205  of the probe  201  includes a “latching clearance” region  259  sized and configured to accommodate relative movement of the recessed area  205  and the finger contacts  211  of the male connector  231  during the push-then-pull operation. For example, the recessed area  205  and/or finger contacts  211  can move along an axis of the probe  201 , with the finger contacts  211  being at least partially disposed within the latching clearance region  259 . In certain exemplary embodiments, an end  260  of each finger contact  211  can abut an end  261  of the recessed area  205 , within the latching clearance region  259 , when the push portion of the push-then-pull operation is completed. 
     A person of ordinary skill in the art having the benefit of the present disclosure will recognize that the clearances described herein are merely exemplary in nature and that other suitable clearances and other suitable means exist for accommodating relative movement between the connectors during a push operation. 
     The relative movement of the connectors  221 ,  231  during the push-then-pull operation can vary depending on the sizes of the connectors  221 ,  231  and the strength of the interface adhesion to be sheared when separating the connectors  221 ,  231 . For example, in certain exemplary embodiments, the relative movement of the connectors  221 ,  231  during the push portion of the push-then-pull operation can be on the order of about 0.1 inches to about 1.0 or more inches or between about 0.2 inches and 1.0 inches. One or both of the connectors  221 ,  231  can move during the push-then-pull operation. For example, one of the connectors  221 ,  231  can remain stationary while the other of the connectors  221 ,  231  moves towards and away from the stationary connector  221 ,  231 . Alternatively, both connectors  221 ,  231  can move towards and away from one another. 
       FIG. 3  is a longitudinal cross-sectional view of a separable connector system  300  similar to the separable connector system  200  of  FIG. 2  in an electrically connected operating position, according to certain exemplary embodiments.  FIG. 4  is a longitudinal cross-sectional view of the separable connector system  300  of  FIG. 3  in a pushed-in position, according to certain exemplary embodiments. 
     In the electrically connected operating position depicted in  FIG. 3 , the female and male connectors  221 ,  231  are electrically and mechanically engaged. Each projection  213  of the finger contacts  211  of the male connector  231  is interlocked with the recessed area  205  of the probe  201  of the female connector  221 . Clearance regions  252 ,  254 ,  257 ,  259  of the connectors  221 ,  231  are sized and configured to accommodate a push-then-pull operation of the connectors  221 ,  231 , substantially as described above with reference to  FIG. 2 . 
     An operator can move one or both of the connectors  221 ,  231  together to the pushed-in position depicted in  FIG. 4 . In the pushed-in position, the connectors  221 ,  231  are more closely interfaced than in the operating position depicted in  FIG. 3 , with portions of each clearance region  252 ,  254 ,  257 ,  259  being substantially filled. In particular, a portion of the nose end  234  of the male connector  231  is at least partially disposed within the nose clearance region  252 ; a portion of the shoulder  255  of the male connector  231  is at least partially disposed within the shoulder clearance region  254 ; a portion of the probe  201  of the female connector  221  is at least partially disposed within the probe clearance region  257 ; and a portion of each finger contact  211  of the male connector  231  is at least partially disposed within the latching clearance region  259 . For example, in the pushed-in position, the connectors  221 ,  231  can engage one another in an interference fit, with no air or only minimal air present in the clearance regions  252 ,  254 ,  257 ,  259 . In certain exemplary embodiments, the nose end  234  of the male connector  231  is at least partially disposed within a faraday cage  190  of the female connector  221 . The faraday cage includes a semi-conductive material, such as molded peroxide-cured EPDM, configured to control electrical stress. 
     Pushing the connectors together, to the pushed-in position depicted in  FIG. 4 , can shear interface adhesion present between the connectors  221 ,  231  in the operating position depicted in  FIG. 3  (hereinafter the “resting position”). Shearing the interface adhesion can make it easier for the operator to separate the connectors  221 ,  231  during an electrical disconnection operation. In particular, the force required to separate the connectors  221 ,  231  after pushing the connectors together can be less than the force required to separate the connectors  221 ,  231  from the resting position. In addition, the distance between the pushed-in position and the resting position can provide a “running start” for overcoming latching force between the finger contacts  211  and the recessed area  205  of the probe  201 . 
       FIG. 5  is a longitudinal cross-sectional view of a separable connector system  500 , according to certain additional alternative exemplary embodiments. The separable connector system  500  includes a male connector assembly  562  and a female connector assembly  564  selectively positionable with respect to the male connector assembly  562 . An operator can engage and disengage the connector assemblies  562 ,  564  to make or break an energized connection in a power distribution network. 
     The female connector assembly  564  includes ganged female connectors  570 ,  571  that each may be, for example, similar to the female connector  102  illustrated in  FIG. 1  and/or the female connector  221  illustrated in  FIGS. 2-4 . The female connectors  570 ,  571  are joined to one another by a connecting housing  572  and are electrically interconnected in series via a bus  590 . The female connectors  570 ,  571  are substantially aligned in parallel with one another on opposite sides of a central longitudinal axis of the system  560 . As such, probes  514  and arc followers  520  of the female connectors  570  and  571  are aligned in parallel fashion about the axis  560 . 
     In certain exemplary embodiments, the male connector assembly  562  includes stationary male connectors  582 ,  583  that correspond to and are aligned with the female connectors  570 ,  571 . For example, each of the male connectors  582 ,  583  may be similar to the male connector  104  shown in  FIG. 1  and/or the male connector  231  shown in  FIG. 2 . In certain exemplary embodiments, one of the male connectors  582 ,  583  may be connected to a dead front electrical apparatus (not shown), and the other of the male connectors  582 ,  583  may be connected to a power cable (not shown) in a known manner. For example, one of the male connectors  582 ,  583  may be connected to a vacuum switch or interrupter assembly (not shown) that is part of the dead front electrical apparatus. 
     In certain exemplary embodiments, the male connectors  582 ,  583  can be mounted in a stationary manner to the dead front electrical apparatus. For example, the male connectors  582 ,  583  may be mounted directly to the dead front electrical apparatus or via a separate mounting structure (not shown). The male connectors  582 ,  583  are maintained in a spaced apart manner, aligned with the female connectors  570 ,  571  such that, when the female connectors  570 ,  571  are moved along the longitudinal axis  560  in the direction of arrow A, the male connectors  582 ,  583  may be securely engaged to the respective female connectors  570 ,  571 . Likewise, when the female connectors  570 ,  571  are moved in the direction of arrow B, opposite to the direction of arrow A, the female connectors  570 ,  571  may be disengaged from the respective male connectors  582 ,  583  to a separated position. 
     In certain alternative exemplary embodiments, the female connector assembly  564  may be mounted in a stationary manner to the dead front electrical apparatus, with the male connector assembly  562  being selectively movable relative to the female connector assembly  564 . Similarly, in certain additional alternative exemplary embodiments, both the female connector assembly  564  and the male connector assembly  562  may be movable with respect to one another. 
     The separable connector system  500  of  FIG. 5  allows the operator to safely and easily separate the connector assemblies  562 ,  564  using a push-then-pull operation. Each of the connector assemblies  562 ,  564  and their corresponding connectors  570 ,  571 ,  582 ,  583  is sized and configured to accommodate the push-then-pull operation. First, as with the separable connector systems  100 ,  200  of  FIGS. 1 and 2 , respectively, a cup-shaped recess  518  of each female connector  570 ,  571  includes a “nose clearance” region  552  sized and configured to accommodate relative movement of a nose end  534  of its corresponding male connector  582 ,  583  and the cup-shaped recess  518  during the push-then-pull operation. For example, each nose end  534  and/or cup-shaped recess  518  can move along an axis of its corresponding probe  514 , with the nose end  534  being at least partially disposed within its corresponding nose clearance region  552 . In certain exemplary embodiments, an edge  534   a  of each nose end  534  can abut an end  553  of its corresponding cup shaped recess  518 , within the nose clearance region  552 , when the push portion of the push-then-pull operation is completed, i.e., when the connector assemblies  562 ,  564  are completely pushed together. In certain exemplary embodiments, each nose end  534  is at least partially disposed within a faraday cage  590  of the corresponding female connector  570 ,  571 . The faraday cage includes a semi-conductive material, such as molded peroxide-cured EPDM, configured to control electrical stress. 
     Second, a housing  523  of each female connector  570 ,  571  includes a “shoulder clearance” region  554  sized and configured to accommodate relative movement of the housing  523  of the female connector  570 ,  571  and a shoulder  555  of its corresponding male connector  582 ,  583  during the push-then-pull operation. For example, the shoulder  555  and/or the housing  523  can move along an axis parallel to the axis of its corresponding probe  514 , with each shoulder  555  being at least partially disposed within its corresponding shoulder clearance region  554 . In certain exemplary embodiments, an end  555   a  of each shoulder  555  can abut an end  556  of its corresponding housing  523 , within the shoulder clearance region  554 , when the push portion of the push-then-pull operation is completed. 
     Third, a piston holder  532  of each male connector  582 ,  583  includes a “probe clearance” region  557  sized and configured to accommodate relative movement of the piston holder  532  and the probe  514  of the male connector&#39;s corresponding female connector  570 ,  571  during the push-then-pull operation. For example, each probe  514  and/or piston holder  532  can move along an axis of the probe  514 , with the probe  514  being at least partially disposed within the probe clearance region  557 . In certain exemplary embodiments, an end  558  of each probe  514  can abut an end  532   a  of its corresponding piston holder  532 , within the probe clearance region  557 , when the push portion of the push-then-pull operation is completed. 
     Fourth, a recessed area  505  of each probe  514  includes a “latching clearance” region  559  sized and configured to accommodate relative movement of the recessed area  505  and finger contacts  511  of the probe&#39;s corresponding male connector  582 ,  583  during the push-then-pull operation. For example, the recessed area  505  and/or finger contacts  511  can move along an axis of the probe  514 , with the finger contacts  511  being at least partially disposed within the latching clearance region  559 . In certain exemplary embodiments, an end  560  of each finger contact  511  can abut an end  561  of its corresponding recessed area  505 , within the latching clearance region  559 , when the push portion of the push-then-pull operation is completed. 
     A person of ordinary skill in the art having the benefit of the present disclosure will recognize that the clearances described herein are merely exemplary in nature and that other suitable clearances and other suitable means exist for accommodating relative movement between the connector assemblies  562 ,  564  during a push operation. 
     The relative movement of the connector assemblies  562 ,  564  during the push-then-pull operation can vary depending on the sizes of the connector assemblies  562 ,  564  and their corresponding connectors  570 ,  571 ,  582 ,  583 , and the strength of the interface adhesion to be sheared when separating the connector assemblies  562 ,  564 . For example, in certain exemplary embodiments, the relative movement of the connector assemblies  562 ,  564  during the push portion of the push-then-pull operation can be on the order of about 0.1 inches to about 1.0 or more inches or between about 0.2 inches and 1.0 inches. 
       FIG. 6  is a longitudinal cross-sectional view of a separable male connector  600 , according to certain additional alternative exemplary embodiments.  FIG. 7  is a partially exploded isometric view of ganged, separable female connectors  700  and separable male connectors  600  of  FIG. 6  connected to an electrical apparatus  705 . For example, the electrical apparatus  705  can include a capacitor, transformer, switchgear, or other live front or dead front electrical apparatus. 
     The female connectors  700  and male connectors  600  are configured to be selectively engaged and disengaged to make or break an energized connection in a power distribution network including the electrical apparatus  705 . In certain exemplary embodiments, each male connector  600  can be similar to the male connector  104  shown in  FIG. 1  and/or the male connector  231  shown in  FIG. 2 , and each female connector  700  can be similar to the female connector  102  illustrated in  FIG. 1  and/or the female connector  221  illustrated in  FIGS. 2-4 . The connectors  600 ,  700  may or may not include clearance regions for accommodating a push-then-pull operation. 
     Each male connector  600  includes a semi-conductive shield  608  disposed at least partially about an elongated insulated body  636 . The insulated body  636  includes elastomeric insulating material, such as molded peroxide-cured EPDM. A conductive shield housing  632  extends within the insulated body  636 , substantially about a contact assembly  620 . A non-conductive nose piece  634  is secured to an end of the shield housing  632 , proximate a “nose end”  694  of the male connector  600 . The elastomeric insulating material of the insulated body  636  surrounds and bonds to an outer surface of the shield housing  632  and to a portion of the nose piece  634 . 
     The contact assembly  620  includes a conductive piston  622 , female contact  624 , and arc interrupter  628 . The piston  622  includes an axial bore and is internally threaded to engage external threads of a bottom portion  624   a  of the finger contact  624  and thereby fixedly mount or secure the finger contact  624  to the piston  622  in a stationary manner. In certain exemplary embodiments, the piston  622  can be knurled around its outer circumferential surface to provide a frictional, biting engagement with a piston holder  693  to ensure electrical contact therebetween. The piston  622  provides resistance to movement of the finger contact  624  until a sufficient pressure is achieved in a fault closure condition. The piston  622  is positionable or slidable within the shield housing  632  to axially displace the contact assembly  620  in the direction of arrow A during the fault closure condition. For example, arc quenching gas released from the arc interrupter  628  during a fault closure condition can cause the piston  622  to move in the direction of arrow A. 
     The finger contact  624  includes a generally cylindrical contact element with a plurality of axially projecting contact fingers  630  extending therefrom. The contact fingers  630  may be formed by providing a plurality of slots  633  azimuthally spaced around an end of the female contact  624 . The contact fingers  630  are deflectable outwardly when engaged to a probe  715  of a mating, female connector  700  to resiliently engage outer surfaces of the probe  715 . 
     The arc interrupter  628  includes a generally cylindrical member fabricated from a nonconductive or insulative material, such as plastic. In a fault closure condition, the arc interrupter  628  generates de-ionizing, arc quenching gas, the pressure buildup of which overcomes the resistance to movement of the piston  622  and causes the contact assembly  620  to accelerate, in the direction of arrow A, toward the nose end  694  of the male connector  600 , to more quickly engage the finger contact element  624  with the probe  710 . Thus, movement of the contact assembly  620  in fault closure conditions is assisted by arc quenching gas pressure. 
     In certain exemplary embodiments, the nose piece  634  is fabricated from a nonconductive material and is generally tubular or cylindrical. The nose piece  634  is fitted onto the nose end  694  of the male connector  600 , and extends in contact with an inner surface of the shield housing  632 . An external rib or flange  616  is fitted within an annular groove  614  of the shield housing  632 , thereby securely retaining the nose piece  634  to the shield housing  632 . 
     A portion of the nose piece  634  extending from an end  636   a  of the insulated body  636  includes an undercut segment  650  disposed between an outer interface segment  651  and an inner interface segment  652  of the nose piece  634 . Each of the interface segments  651 ,  652  is configured to engage an interior surface of the corresponding female connector  700 . For example, each interface segment  651 ,  652  can be configured to engage semi-conductive material extending along an interior portion of an inner surface of a housing of the female connector  700  (similar to the material  190  illustrated in  FIG. 1 ). The undercut segment  650  is recessed between the interface segments  651 ,  652  so that the undercut segment  650  will not engage the interior surface of the female connector  700  when the male connector  600  and female connector  700  are engaged. In certain exemplary embodiments, the semi-conductive material engaged by the interface segments  651 ,  652  can include at least a portion of a faraday cage of the female connector  700 . Thus, the undercut segment  650  can be disposed beneath the faraday cage. 
     The undercut segment  650  can have any depth greater than zero that causes an outside diameter of the undercut segment  650  to be less than an inside diameter of a corresponding segment of an interior surface of the female connector  700 . For example, the undercut segment  650  can have a depth of at least about 0.05 inches. By way of example only, in certain exemplary embodiments, the undercut segment  650  can have a depth of about 0.27 inches. The length of the undercut segment  650  can vary, depending on the relative sizes of the connectors  600 ,  700 . For example, the undercut segment  650  can have a length of about 0.625 inches. 
     In conventional nose pieces, most or the entire outer surface of the portion of the nose piece extending from the end  636   a  of the insulated body  636  interfaces with the interior surface of the corresponding female connector  700 . The traditional motivation for this design was to prevent partial discharge (“PD”) and encourage voltage containment by having the nose piece and other components of the male connector engage the female connector  700  in a form-fit manner. However, as described above, this form-fit relationship made it difficult for an operator to separate the connectors during an electrical disconnection operation. 
     The exemplary male connector  600  depicted in  FIGS. 6 and 7  addresses this concern by including two interface segments  651 ,  652  for preventing PD and encouraging voltage containment, while limiting the surface area of the nose piece  634  that interfaces with the interior surface of the female connector  700 . In certain exemplary embodiments, the total surface area may be reduced by about 20% to about 40% or more, thereby reducing a surface tension between the male and female connectors  600 ,  700  that must be overcome when separating the connectors  600 ,  700 . 
     This reduction in surface area allows air to rest between the undercut segment  650  and the interior surface of the female connector  700 , reducing a pressure drop within the female connector  700  when separating the connectors  600 ,  700 . For example, the reduction in pressure drop can make separation of the connectors  600 ,  700  easier to perform because less suction works against the operator. The reduction in pressure also can improve switching performance because there is less likelihood of partial vacuum induced flashover. As described below with reference to  FIG. 8 , in certain alternative exemplary embodiments, the total surface area of the nose piece may be reduced up to 100%. For example, the nose piece  634  may include only one or no interface segments in certain alternative exemplary embodiments. 
     In certain exemplary embodiments, the undercut segment  650  also may function as a locking groove, substantially as described above with reference to  FIG. 1 . For example, the undercut segment  650  may include a latching clearance region sized and configured to accommodate relative movement of the locking groove and a locking ring of the female connector  700  during a push-then-pull operation. 
     In certain alternative exemplary embodiments, the connector  600  may include both an undercut segment  650  and another locking groove (not shown) configured to receive a locking ring (not shown) of the female connector  700 . For example, the insulated body  636  proximate the undercut segment  650  may include the locking groove. The locking groove may or may not include a latching clearance region for accommodating a push-then-pull operation. 
       FIG. 8  is a longitudinal cross-sectional view of a separable male connector  800 , according to certain additional alternative exemplary embodiments. The male connector  800  is substantially similar to the male connector  600  of  FIGS. 6-7 , except that the connector  800  includes a different shaped nose piece  834  than the nose piece of the connector  600  of  FIGS. 6-7 . 
     Specifically, the connector  800  includes a nose piece  834  including an undercut segment  850  without interfacing segments. Thus, no portion of the nose piece  834  will engage an interior surface of a corresponding female connector (not shown in  FIG. 8 ) when the connectors are connected. Other portions of a nose end  894  of the connector  800  may interface with the interior surface of the female connector to prevent PD and to encourage voltage containment. For example, an outer surface  636   b  of a portion of the insulated body  636  of the connector  800  may engage the interior surface of the Faraday cage when the connectors are connected. Thus, the connector  800  addresses PD prevention and voltage containment while limiting the surface area of the nose piece  834  that interfaces with the interior surface of the female connector. Similarly, an outer surface  896   a  of a contact tube  896  of the connector  800  may or may not engage the interior surface when the connectors are connected. As set forth above, this reduction in surface area allows air to rest between the undercut segment  850  and the interior surface of the female connector, making it easier to separate the connectors when the connectors are disconnected. 
     Although specific embodiments of the invention have been described above in detail, the description is merely for purposes of illustration. It should be appreciated, therefore, that many aspects of the invention were described above by way of example only and are not intended as required or essential elements of the invention unless explicitly stated otherwise. Various modifications of, and equivalent steps corresponding to, the disclosed aspects of the exemplary embodiments, in addition to those described above, can be made by a person of ordinary skill in the art without departing from the spirit and scope of the present invention defined in the following claims, the scope of which is to be accorded the broadest interpretation so as to encompass such modifications and equivalent structures.