Abstract:
A removable telecommunication sensor module is configured to be removably coupled between a power protection device and a backplane. The removable telecommunication sensor module monitors energy usage at a telecommunication equipment circuit level for a piece of telecommunication equipment arranged in a telecommunication network infrastructure.

Description:
BACKGROUND 
     Existing telecommunications energy monitoring methods are very coarse. For instance, energy management systems and methods have traditionally been utilized at a site level (e.g., a central office site or a wireless site). For example, historically a telecommunication organization simply monitored energy consumption of a single site by way of regularly comparing the site&#39;s utility bills from month to month. While this approach helps ensure that the telecommunication site&#39;s energy consumption is at least consistent, it does not provide visibility to power consumption by each piece of telecommunication equipment arranged in the telecommunication site. Further, while this approach provides visibility to the telecommunication site&#39;s energy consumption infrequently (i.e., month to month) it does not provide visibility to power consumption by each piece of telecommunication equipment arranged in the telecommunication site on demand, in real-time, or without perceivable delay. 
     As such, telecommunications companies are beginning to monitor power consumption at a power distribution system level. Specifically, telecommunications companies are beginning to monitor power consumption at a primary power distribution level (e.g., a battery distribution feeder bay (BDFB)). For example, a telecommunications company may monitor energy consumption of a primary power distribution system by monitoring a current shunt monitor of the primary power distribution system. While this approach provides visibility to power consumption at the primary power distribution level, it also does not provide visibility to power consumption by each piece of telecommunication equipment arranged in the telecommunication site. The removable telecommunication sensor modules described herein address these problems by providing integrated current monitoring functionality into a separate fuse holder. By integrating current monitoring functionality into the fuse holder this provides a removable telecommunication sensor module having a slim profile that produce a high density of power distribution devices (e.g., number of breaker slots and/or fuse slots per one rack unit (1RU)). Further, by integrating current monitoring functionality into the fuse holder this simplifies the current monitoring architecture, lowers assembly cost, frees up printed circuit board assembly (PCA) space, and reduces maintenance in the event of a failure. 
     SUMMARY 
     This summary is provided to introduce simplified concepts for removable telecommunication sensor modules and a method of using the same, which is further described below in the Detailed Description. This summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter. 
     A removable telecommunication sensor module is provided to monitor energy usage at a telecommunication equipment circuit level for a piece of telecommunication equipment arranged in a telecommunication network infrastructure. 
     In one example, a removable sensor module may be removeably coupled between a power protection device and a backplane (e.g., printed circuit board assembly (PCA)) as a self-contained stand-alone single unit. The self-contained stand-alone removable sensor module may be easily inserted into a slot of a power distribution system (e.g., a secondary power distribution panel) and removably coupled to the backplane. A power protection device may also subsequently be inserted into the same slot and removably coupled to the self-contained removable sensor module. One removable sensor module may monitor a load output of a piece of telecommunication equipment. 
     In one example, the removable sensor module may comprise one or more electrical contact pads arranged on top of a current monitoring assembly (e.g., a printed circuit assembly (PCA)) to directly contact with an electrical contact portion of a power protection device. The removable sensor module may comprise one or more electrical contact clips arranged above the electrical contact pads. The electrical contact clips may be arranged to apply a force on the electrical contact portion of the power protection device to force the electrical contact portion of the power protection device onto the one or more electrical contact pads arranged on the PCA. 
     In one example, the current monitoring assembly may include one or more power input and power output contacts arranged to removeably couple with a backplane. The current monitoring assembly may also include one or more unprotected traces arranged between the one or more clips and the one or more power output contacts to dissipate heat from the one or more unprotected traces directly to ambient air. 
     In another example, the removable sensor module may comprise a cover arranged to cover only a first side of the current monitoring assembly and not a second side opposite the first side. By covering only the first side, the cover protects components (e.g., sensors, monitors, resistors, capacitors, transistors, field-effect transistors (FETs), traces, etc.) fixed to the first side of the current monitoring board, while providing for the one or more unprotected traces, arranged on the second side, to dissipate heat directly to ambient air. 
     In another example, the removable sensor module may comprise a current monitor arranged on the current monitoring assembly. The current monitor may be arranged on the first side of the current monitoring assembly and protected by the cover. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description is described with reference to the accompanying figures. The use of the same reference numbers in different figures indicates similar or identical items. 
         FIG. 1  illustrates an example implementation of a removable sensor module for use in a power distribution system. 
         FIG. 2  is a top section view of a removable sensor module installed in a slot of the power distribution system taken along section line A-A of  FIG. 1 . 
         FIG. 3A  is a top view of the printed circuit assembly (PCA) and power protection device of the removable sensor module illustrated in  FIG. 1 . 
         FIG. 3B  is a bottom view of the printed circuit assembly (PCA) and power protection device of the removable sensor module illustrated in  FIG. 1 . 
         FIG. 3C  is a side view of the printed circuit assembly (PCA) and power protection device of the removable sensor module illustrated in  FIG. 1 . 
         FIG. 4A  is a bottom view of the cover and power protection device of the removable sensor module illustrated in  FIG. 1 . 
         FIG. 4B  is a top view of the cover and power protection device of the removable sensor module illustrated in  FIG. 1 . 
         FIG. 4C  is a side view of the cover and power protection device of the removable sensor module illustrated in  FIG. 1 . 
         FIG. 4D  is a front view of the cover and power protection device of the removable sensor module illustrated in  FIG. 1 . 
         FIG. 5  illustrates another example implementation of a removable sensor module for use in power distribution system. 
         FIG. 6  illustrates another example implementation of a removable sensor module for use in power distribution system. 
     
    
    
     DETAILED DESCRIPTION 
     Overview 
     This disclosure is directed to removable telecommunication sensor modules and a method of using the same. The removable sensor modules are easily installed and/or replaced. The removable sensor modules may comprise a current monitoring assembly (e.g., a printed circuit assembly (PCA)) and a cover fixed to the current monitoring assembly and covering a single side of the current monitoring assembly. The cover provides protection for the components and provides for removably installing the removable sensor module into a slot of a power distribution system (e.g., a secondary power distribution panel). 
     The current monitoring assembly may include one or more single sided clips fixed to a first end of the current monitoring assembly. Each of the one or more single sided clips may be arranged above an electrical contact pad (e.g., an exposed trace) arranged on top of a first planar surface of the current monitoring assembly. The one or more single sided clips and contact pads may cooperatively couple with an electrical contact portion of a power protection device. 
     Because the power protection device is directly in contact with the electrical contact pad (i.e., there is no power protection device housing between the power protection device and the current monitoring assembly), the removable sensor modules have a thinner profile exhibited by a thin thickness as compared to removable sensor modules having a housing fixed on the current monitoring assembly. This is because without the housing or receptacle between the power protection device and the current monitoring assembly, the power protection device is positioned closer to the current monitoring assembly than a power protection device housed in a housing fixed on the current monitoring assembly. 
     Also, because the removable sensor modules have a thin profile exhibited by a thin thickness, this reduces bowing (e.g., a displacement, a deformation, a deflection, etc.) of the current monitoring assembly when mating the removable sensor module to a backplane. This is because the power protection device is positioned directly in contact with the current monitoring assembly, which reduces a distance (i.e., a lever-arm distance) from the current monitoring assembly to the power protection device receptacle. The reduced lever-arm distance reduces the bowing of the current monitoring assembly during installation and/or removal of the current monitoring assembly. 
     Further, because the power protection device is directly in contact with the electrical contact pad, the removable sensor modules provide a lower electrical and thermal resistance than removable sensor modules having a housing fixed to a current monitoring assembly. This is because the removable sensor modules not having a housing fixed to the current monitoring assembly do not have the added electrical and/or thermal resistances produced by a housing arranged between the power protection device and the current monitoring assembly. Thus, the electrical and thermal resistance circuits of the removable sensor modules not having a housing arranged between the power protection device and the current monitoring assembly have fewer electrical and thermal resistance junctions than removable sensor modules having a housing arranged between the power protection device and the current monitoring assembly. 
     Further, because the removable sensor modules do not have a housing fixed to the current monitoring assembly, this reduces a quantity of components needed for manufacturing the current monitoring assembly. This produces a lower cost of manufacturing the removable sensor modules not having a housing fixed to the current monitoring assembly, than a cost of manufacturing removable sensor modules having a housing fixed to the current monitoring assembly. 
     The current monitoring assembly may include one or more power input and power output contacts and/or one or more signal contacts arranged in a second end, opposite the first end, of the current monitoring assembly. The one or more power input and power output contacts and/or one or more signal contacts may provide for connecting the removable sensor modules to a backplane and/or a harness. The one or more signal contacts may pass signals to a central control board. The one or more power input and power output contacts may provide for passing current to a load (e.g., a piece of telecommunications equipment). 
     The current monitoring assembly may include a current monitor or current sensor. In some implementations, the current monitor may be a Hall Effect current monitor fixed on the first planar surface of the current monitoring assembly. The current monitor may monitor and report a current flowing through one or more unprotected power input and power output traces for the load. The current monitor may pass signals to the central control board. 
     Because, in this example, the removable sensor modules are self-contained single units, the removable sensor modules may be installed in the same single slot as a commercial off-the-shelf (COTS) power protection device (e.g., a breaker and/or a fuse). This provides for cost effective replacement and upgrade. For example, because the removable sensor modules are self-contained single units a user may simply replace a removable sensor module without having to replace a breaker and/or a fuse as well. Further, because the removable sensor modules are self-contained single units a user may simply replace a breaker and/or a fuse without having to replace a sensor. 
     In addition, because the removable sensor modules may be installed in the same single slot as a commercial off-the-shelf (COTS) breaker and/or fuse, a breaker and/or fuse panel density (i.e., number of breaker slots and/or fuse slots per one rack unit (1RU)) may be maintained. For example, because the removable sensor modules are self-contained as single units, the power protection devices remain intact. This eliminates any modification of the power protection devices. As such, the size of the power protection devices remains intact (i.e., remains stock COTS size) and likewise the breaker and/or fuse panel density remains intact. Further, the function of the power protection devices remains intact and as such the reliability of the power protection devices remains intact. 
     While the illustrated embodiments show secondary power distribution panels comprising breakers and/or fuses, the breakers and fuses may be of any type of power protection devices suitable for use in power systems. For example the breakers and/or fuses may be TPS, TLS, breakers, KTK, KLM, TPC, GMT “grasshopper” type power protection devices. Further, while the illustrated embodiments show secondary power distribution panels suitable for powering telecommunications equipment configured to utilize −48 VDC, +24 VDC, or other voltages, suitable for powering telecommunications equipment, the secondary power distribution panels may be of any type of power distribution panels. For example, the power distribution panels may be a distribution board, panel board, electrical panel, service panel, load center, or the like. 
     Further, while the illustrated embodiments show power distribution systems configured as fuse panels, the power distribution systems may be configured in a variety of ways to provide power distribution in a single compact unit. For example, the power distribution systems may be configured as breaker panels, dual-feed panels, combination breaker/fuse panels, combination dual-feed breaker/fuse panels, or the like. 
     The power distribution systems may be configured to be installed in a cabinet, a rack, an enclosure, a chassis, a housing, or the like. For example, the power distribution systems may be installed in a rack and consume four rack units (4RUs) of the rack. In another example, the power distribution systems may be installed in a rack and consume 1RU of the rack. 
     Further, a cabinet may be configured in a variety of ways to maintain or hold a plurality of components in a telecommunications infrastructure. For example, a cabinet may be configured as a cabinet for a primary power distribution panel (e.g., a battery distribution feeder bay (BDFB)), a secondary power distribution panel (e.g., a breaker panel and/or a fuse panel) a housing, a terminal block, a panel, a chassis, a digital cross-connect, a switch, a hub, a rack, a frame, a bay, a module, an enclosure, an aisle, or other structure for receiving and holding a plurality of components. 
     Example Monitoring Systems 
       FIG. 1  illustrates an example implementation of a removable sensor module  102  for use in a power distribution system  104 . The removable sensor module  102  may be inserted as a single unit into a slot  106  of the power distribution system  104 . For example, a user can easily install and/or replace a removable sensor module  102  which requires only front access because of the removable sensor module&#39;s  102  blind-mate installation. This provides for replacing failed removable sensor modules  102  or upgrading from “non-monitoring” to monitoring removable sensor modules  102 . Further, this provides for switching to a different current range (e.g., switching from a 15 A max version to a 20 A max version). 
     The removable sensor module  102  may include a printed circuit assembly (PCA)  108 . The PCA  108  may have a first end  110 (A) opposite a second end  110 (B), and a first planar surface  112 (A) opposite a second planar surface  112 (B). The removable sensor module  102  may include a cover  114 . In one example, the cover  114  may be arranged to only cover the first planar surface  112 (A) of the PCA  108 , and not cover the second planar surface  112 (B). The cover  114  may include a receptacle  116  for removably coupling with a power protection device  118 . For example, the receptacle  116  may be configured as a fuse holder (e.g., a GMT type fuse holder), and formed integral with the cover  114 . For example, the cover  114  and the receptacle  116  may be formed as a single unit of material. The cover  114  and the receptacle  116  may be formed as a single unit of plastic (e.g., high density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinylchloride (PVC), polychlorotrifluoroethylene (PCTFE or PTFCE), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), etc.). While the receptacle  116  is illustrated as comprising a GMT type fuse holder, the receptacle  116  may be a KTK, KLM, TPA, TPC, TPS, TLS or the like, type fuse holder. 
     The removable sensor module  102  may comprise power input and power output contacts  120 (A) and  120 (B) arranged in the second end  110 (B) of the PCA  108 . For example, the power input and power output contacts  120 (A) and  120 (B) may be unprotected or exposed traces arranged in the first planar surface  112 (A) and/or the second planar surface  112 (B). The power input and power output contacts  120 (A) and  120 (B) may provide for removably coupling with an internal electrical component  122  (e.g., a backplane, a harness, a bus bar, etc.). For example, the power input and power output contacts  120 (A) and  120 (B) may provide for removably coupling with cooperating power input and power output connectors  124 (A) and  124 (B) to make an electrical connection with the internal electrical component  122 . While the power input and power output contacts  120 (A) and  120 (B) are illustrated as comprising unprotected traces and the cooperating power input and power output connectors  124 (A) and  124 (B) are illustrated as comprising cooperating card edge style connectors, the power input and power output contacts  120 (A) and  120 (B) and cooperating power input and power output connectors  124 (A) and  124 (B) may additionally or alternatively utilize pins, headers, clips, or the like to make an electrical connection with the internal electrical component  122 . 
     The removable sensor module  102  may comprise a current monitor  126 , shown in  FIG. 1  in dashed lines to illustrate that the current monitor  126  is arranged behind the cover  114 , and arranged on the PCA  108 . The current monitor  126  may be arranged on the PCA  108  between the first end  110 (A) and the second end  110 (B) of the PCA  108 . The current monitor  126  may provide for monitoring a current flowing through the removable sensor module  102  and reporting of a signal based on the monitored current. The current monitor  126  may be a Hall Effect current monitor. While  FIG. 1  illustrates a removable sensor module  102  having a current monitor  126  arranged on the PCA  108 , in other embodiments the removable sensor module  102  may not have a current monitor  126  arranged on the PCA  108 . In such an implementation, the removable sensor module  102  may be devoid of current monitoring hardware and may be a “non-monitoring” removable sensor module  102 . For example, the “non-monitoring” removable sensor module  102  may pass a current from the power protection device  118  to the internal electrical component  122  (e.g., a backplane, a harness, a bus bar, etc.) without monitoring a current passing through the removable sensor module  102 . 
     The removable sensor module  102  may comprise a signal pin header  128 (A) fixed to the second end  110 (B) of the PCA  108 . The signal pin header  128 (A) may provide for removably coupling with cooperating signal pins  128 (B) of the internal electrical component  122 . The signal pin header  128 (A) and cooperating signal pins  128 (B) may provide signal contacts with the internal electrical component  122 . The signal pin header  128 (A) and cooperating signal pins  128 (B) may provide for receiving and/or reporting signals to and/or from a central control board. 
     The removable sensor module  102  may have external dimensions that are driven, or otherwise constrained by the dimensions of the power protection device  118 , and likewise the dimensions of the slot  106 . For example, the power protection device  118  may be a GMT type fuse having a standard height  130  of about 0.7 inches (18 millimeters), a standard width  132  of about 0.1 inches (2 millimeters), and a standard depth  134  of about 0.8 inches (20 millimeters). However, in other examples the power protection device  118  may be a TPS, TLS, KTK, KLM, etc. type power protection device. 
     Detail view  136  illustrates that the slot  106  may have an opening also having dimensions driven by the dimensions of the power protection device  118 . For example, the slot  106  may have an opening having dimensions capable of receiving a portion of the GMT type fuse. In this embodiment, where the slot  106  has an opening to receive a GMT type fuse, the slot  106  may have an opening having a height  138  of about 1.3 inches (33 millimeters) and a width  140  of about 0.5 inches (13 millimeters). The removable sensor module  102  may have a height  142  of about 1.3 inches (33 millimeters) and a width  144  of about 0.5 inches (13 millimeters) for cooperating with the slot  106  and the power protection device  118 . However, the removable sensor modules  102  may have a height and width for cooperating with a slot and a TPS, TLS, KTK, KLM, or the like type power protection device. 
     The cover  114  may provide for securing the removable sensor module  102  in the slot  106 . For example, a user can easily removably install each removable sensor module  102  as a single unit into a slot  106  of the power distribution system  104  via a blind-mate installation. For example, a user may insert a removable sensor module  102  into a slot  106  and removably connect the power input  120 (A), the power output  120 (B), and/or the signal pin header  128 (A), to the internal electrical component  122  (e.g., backplane). A user may removably fasten the cover  114  to a front surface  146  of the power distribution system  104  via a latch  148  and a rail  150  arranged in the cover  114 , securing the removable sensor module  102  to the power distribution system  104 . For example, detail view  136  illustrates the slot  106  may include a groove  152  arranged in a bottom surface  154  of the power distribution system  104  to slidably receive the rail  150  of the cover  114 . 
     Detail view  156  illustrates the groove  152  may include a gap  158  arranged in the bottom surface  154  of the power distribution system  104 . The gap  158  may have a width  160  of about the same as a thickness of the rail  150  of the cover  114 . For example, an edge of the rail  150  may have a thickness of about 0.02 inches (0.5 millimeters), and likewise the gap  158  may have a width  160  of about 0.02 inches (0.5 millimeters). The gap  158  may slidably receive the edge of the rail  150 . For example, a user may removably install the removable sensor module  102  into a slot  106 , and slidably displace the edge of the rail  150  along the gap  158  to blind-mate the removable sensor module  102  with the internal electrical component  122 . 
     Detail view  156  further illustrates that the groove  152 , may comprise another gap  162  arranged in the bottom surface  154  of the power distribution system and interconnected with the gap  158 . The other gap  162  may have a width  164  wider than the width  160  of the gap  158  to slidably receive a flange of the rail  150 . For example, a user may removably install the removable sensor module  102  into a slot  106 , and slidably displace the flange of the rail  150  along the other gap  162  to blind-mate the removable sensor module  102  with the internal electrical component  122 . The flange of the rail  150  and the other gap  162  may cooperate to prevent the removable sensor module  102  from being displaced vertically relative to the power distribution system  104 . For example, the flange of the rail  150  may interfere with a surface of the other gap  162  to prevent or keep the removable sensor module  102  from being displaced vertically up towards the power distribution system  104  as the removable sensor module  102  is removably installed in the power distribution system  104 . Further, when the removable sensor module  102  is removably installed in a slot  106 , a bottom surface of the flange of the rail  150  and the bottom surface  154  of the power distribution system  104  may be substantially coplanar or flush with each other. For example, a plurality of power protection devices  118  may be removably installed in a 17.5 inch (444 millimeters), one rack unit (1RU) power distribution system (i.e., power distribution system  104 ), and the bottom (i.e., bottom surface of the rail  150 ) of each of the power protection devices  118  may be substantially coplanar with the bottom surface  154  of the power distribution system  104 . 
     The latch  148  may provide a snap, spring lever, or other mechanism that provides tool-less insertion and removal of the removable sensor module  102 . For example, the latch  148  may provide for being vertically displaced (e.g., snap or spring up and/or down) relative to the removable sensor module  102  to be removably latched to the front surface  146  of the power distribution system  104 . For example, the latch  148  may be vertically displaced down towards the removable sensor module  102  when the latch interferes with the edge of the opening of the slot  106 . In addition to being displaced vertically down towards the removable sensor module  102 , the latch  148  may be vertically displaced up away from the removable sensor module  102  when the latch does not interfere with the edge of the opening of the slot  106 . For example, after the removable sensor module  102  is inserted into the slot  106 , the latch  148  displaces vertically up, away from the removable sensor module  102 , to latch in behind the front surface  146 . 
     Further, while  FIG. 1  illustrates a portion the front surface  146  of the power distribution system  104  having about 10 removable sensor modules  102 , the power distribution system  104  may include additional removable sensor modules  102  arranged in the front surface  146 . For example, the front surface  146  of the power distribution system  104  may include about another 10 removable sensor modules  102  removably received in slots  106  arranged in another half portion of the front surface  146  of the power distribution system  104 . 
       FIG. 1  also illustrates a section line A-A. The section line A-A is proximate to a removable sensor module  102  removably received in a slot  106  of the power distribution system  104 . 
       FIG. 2  illustrates a top section view of the removable sensor module  102  removably received in the slot  106  of the power distribution system  104  taken along the section line A-A illustrated in  FIG. 1 , without the power protection device  118  removably coupled with the receptacle  116  of the cover  114 . 
       FIG. 2  illustrates the removable sensor module  102  removably coupled to the internal electrical component  122 . For example,  FIG. 2  illustrates the power input and power output contacts  120 (A) and  120 (B) removably coupled with the cooperating power input and power output connectors  124 (A) and  124 (B). The removably coupled power input and power output contacts  120 (A) and  120 (B) and cooperating power input and power output connectors  124 (A) and  124 (B) may pass a current to a load of a piece of telecommunication equipment. The current monitor  126  may provide for monitoring the current and reporting of a signal based on the monitored current to a central control board. 
       FIG. 2  further illustrates the signal pin header  128 (A) removably coupled with cooperating signal pins  128 (B) of the internal electrical component  122 . The removably coupled signal pin header  128 (A) and cooperating signal pins  128 (B) may pass signals to a central control board. Further, the PCA  108  may comprise one or more digital inputs and/or outputs, one or more analog inputs and/or outputs, and be communicatively coupled with power sensors. 
     The PCA  108  may include one or more clips  202 (A) and  202 (B). The one or more clips  202 (A) and  202 (B) may be fixed to the first end  110 (A) and arranged above one or more electrical contact pads  204 (A) and  204 (B) arranged on top of the first planar surface  112 (A). The one or more clips  202 (A) and  202 (B) and the one or more electrical contact pads  204 (A) and  204 (B) may be arranged to cooperatively couple with an electrical contact portion of the power protection device  118 . For example, the electrical contact portion of the power protection device  118  may make a direct contact with the one or more electrical contact pads  204 (A) and  204 (B) and provide a path for a current of a load of a piece of telecommunication equipment. The one or more clips  202 (A) and  202 (B) may maintain a force (e.g., a spring force), in the direction towards the PCA  108 , against the electrical contact portion of the power protection device  118 . The force applied by the one or more clips  202 (A) and  202 (B) may force the electrical contact portion of the power protection device  118  against the one or more electrical contact pads  204 (A) and  204 (B) on the PCA  108 . The one or more clips  202 (A) and  202 (B) may be made of and/or coated with a conductive material (e.g., brass, copper, steel, aluminum, silver, gold, etc.), and also provide a path for the current of the load of a piece of telecommunication equipment. The one or more clips  202 (A) and  202 (B) may also dissipate heat. 
     While  FIG. 2  illustrates the one or more clips  202 (A) and  202 (B) as a thru-hole mount design, other clip mountings are contemplated. For example, the one or more clips  202 (A) and  202 (B) may be a surface mount design. 
     Because the power protection device  118  makes a direct contact with the one or more electrical contact pads  204 (A) and  204 (B) (i.e., no power protection device housing between the power protection device  118  and the PCA  108 ), the power protection device  118  is positioned directly on the PCA  108 . With the power protection device  118  positioned directly on the PCA  108 , the power protection device  118  is positioned closer to the PCA  108  of the removable sensor module  102 , than if the power protection device  118  was housed in a housing fixed to the PCA  108 . Thus, the removable sensor module  102  has a thinner profile exhibited by the thin width  144  as compared to a removable sensor module having a power protection device housing fixed to the PCA  108 . This is because the thin width  144  does not include at least the additional thickness of a wall of the power protection device housing fixed to the PCA  108 . With the removable sensor module  102  having a thinner profile exhibited by the thin width  144  as compared to a removable sensor module having a power protection device housing fixed to the PCA  108 , when a force is exerted on the receptacle  116  to removably install the removable sensor module  102 , the thin width  144  reduces an amount of deforming or bowing of the PCA  108 . This is because the receptacle  116 , the PCA  108 , and the one or more power input and power output contacts  120 (A) and  120 (B) are arranged in a near perfect line exhibited by the thin width  144  of the removable sensor module  102 . The thin profile exhibited by the thin width  144  of the removable sensor module  102  provides for better structural integrity during insertion and/or removal of the removable sensor module  102 . This is because thin width  144  reduces a distance (i.e., a lever-arm distance) from the PCA  108  to the receptacle  116 . The reduced lever-arm distance from the PCA  108  to the receptacle  116  reduces the bowing of the PCA  108  during installation and/or removal of the removable sensor module  102 . 
     Further, because the cover  114  is arranged to only cover the first planar surface  112 (A) of the PCA  108 , and not to cover the second planar surface  112 (B), the thin width  144  of the removable sensor module  102  is maintained. This is because the second planar surface  112 (B) of the PCA  108  acts as one side of the removable sensor module  102 . For example, the PCA  108  itself is used to complete the removable sensor module  102  assembly via acting as one side of the removable sensor module  102  opposite the cover  114 . Thus, the removable sensor module  102  maintains the thin profile exhibited by the thin width  144 . 
     Because the removable sensor module  102  exhibits the thin width  144 , more power protection devices  118  per area can be utilized in the power distribution system  104  while providing for airflow over the PCAs  108 . For example, the power distribution system  104  may comprise a 17.5 inch (444 millimeters), one rack unit (1RU) chassis, and because the removable sensor module  102  comprises the thin width  144 , 20 power protection devices  118  may be utilized in the 17.5 inch (444 millimeters), 1RU chassis while allowing airflow over each PCA  108  of each removable sensor module  102 . Because the removable sensor modules  102  and the power protection devices  118  are separate units and are removable relative to each other, and removable relative to the power distribution system  104 , the removable sensor modules  102  lower assembly cost and reduce maintenance time in the event of a failure. 
     The PCA  108  may be fixed to the cover  114 . For example, the PCA may be fixed to the cover  114  via a snap-fit, press-fit, an adhesive, heat stakes, slots, tabs, or any other fastening mechanism suitable to fix the PCA  108  to the cover  114 . 
     The removable sensor module  102  may include a light-emitting diode (LED)  206  to indicate the status of the circuit (e.g., tripped or blown fuse or circuit is on). The LED  206  may be arranged on the PCA  108  and in-line with a light pipe  208  terminating in a front of the removable sensor module  102 . For example, the light pipe  208  may be arranged below the receptacle  116  and distal to the front surface  146  of the power distribution system  104  to be visible to a user. Alternatively, the LED  206  could be arranged in the cover  114  and electrically connected to the PCA  108 . 
       FIG. 3A  illustrates a top view of the PCA  108  and the power protection device  118  of the removable sensor module  102  illustrated in  FIG. 1 .  FIG. 3A  illustrates the one or more clips  202 (A) and  202 (B) and the cooperating one or more electrical contact pads  204 (A) and  204 (B) arranged on top of the first planar surface  112 (A) to removably receive the power protection device  118 . For example, the one or more clips  202 (A) and  202 (B) and the cooperating one or more electrical contact pads  204 (A) and  204 (B) may removably receive one or more electrical portions  302 (A) and  302 (B) (e.g., electrically conductive power input and/or power output metal contacts) of the power protection device  118 . 
     The PCA  108  may comprise a clip  304  arranged in the first planar surface  112 (A) to catch an indicating flag  306  when a fuse  308  of the power protection device  118  is tripped. For example, when a load output of a piece of telecommunication equipment exceeds a max current (e.g., 10 A, 15 A, 20 A, 25 A, etc., max current), the fuse  308  may be tripped, releasing the indicating flag  306 , allowing the indicating flag  306  to move or spring away from the power protection device  118 . Subsequent to the indicating flag  306  being released, the clip  304  interferes or catches the released indicating flag  306 . Prior to the clip  304  interfering with the indicating flag  306 , the LED may indicate the circuit is on. Subsequent to the clip  304  interfering with the indicating flag  306 , the LED may indicate the fuse  308  is tripped. 
     While  FIG. 3A  illustrates the PCA  108  comprising the current monitor  126 , the PCA  108  may not include the current monitor  126 . For example, the PCA  108  may comprise other circuit board configurations with functions other than current monitoring. For example, the PCA  108  may comprise components to monitor a temperature, monitor a voltage, log data, and/or transmit data. The configuration of the PCA may define the configuration of the removable sensor module  102 . 
       FIG. 3B  illustrates a bottom view of the PCA  108  and the power protection device  118  of the removable sensor module  102  illustrated in  FIG. 1 .  FIG. 3B  illustrates one or more unprotected power input and power output traces  310 (A) and  310 (B) arranged on top of the second planar surface  112 (B), and arranged between the one or more clips  202 (A) and  202 (B) and the one or more power input and power output contacts  120 (A) and  120 (B). The one or more unprotected power input and power output traces  310 (A) and  310 (B) may also be arranged between the one or more electrical contact pads  204 (A) and  204 (B). The one or more unprotected power input and power output traces  310 (A) and  310 (B) may electrically connect the one or more clips  202 (A) and  202 (B) and cooperating one or more electrical contact pads  204 (A) and  204 (B), and the one or more power input and power output contacts  120 (A) and  120 (B). 
     The one or more unprotected power input and power output traces  310 (A) and  310 (B) arranged on top of the second planar surface  112 (B) may dissipate heat directly to ambient air. For example, because the second planar surface  112 (B) of the PCA  108  is arranged vertically in the slot  106 , and the cover  114  does not cover the second planar surface  112 (B), the unprotected power input and power output traces  310 (A) and  310 (B) are arranged to dissipate heat directly into ambient air. For example, the unprotected power input and power output traces  310 (A) and  310 (B) arranged on the uncovered second planar surface  112 (B) may dissipate heat from the power protection device  118  electrically connected between the one or more clips  204 (A) and  204 (B) and the one or more electrical contact pads  204 (A) and  204 (B). 
     While the one or more power input and power output contacts  120 (A) and  120 (B) are illustrated in  FIGS. 3A and 3B  as terminating in a rear edge of the PCA  108 , the one or more power input and power output contacts  120 (A) and  120 (B) may extend out of a top edge and/or a bottom edge of the PCA  108 . For example, the one or more power input and power output contacts  120 (A) and  120 (B) may extend out of a top edge and/or a bottom edge of the PCA  108  to create a 90° removable sensor module  102 . 
     The PCA  108  may include an alignment slot  312  arranged in the first end  110 (A) of the PCA  108  for accepting a tab  314  arranged in an exterior surface of the power protection device  118 . The alignment slot  312  provides for the receptacle  116  to slidably receive the power protection device  118 , and provides for securing the removably received power protection device  118  in the removable sensor module  102 . 
       FIG. 3C  illustrates a side view of the PCA  108  and the power protection device  118  of the removable sensor module  102  illustrated in  FIG. 1 .  FIG. 3C  illustrates a gap  316  between the one or more clips  202 (A) and  202 (B) and cooperating one or more electrical contact pads  204 (A) and  204 (B) to removably receive the power protection device  118 . The gap  316  may be about the same as the width  132  of the power protection device  118 . For example, the width  132  of the power protection device  118  may be about 0.1 inches (2 millimeters) and the gap  316  may be about 0.1 inches (2 millimeters) wide. Because the gap  316  is about the same as the width  132 , the one or more clips  202 (A) and  202 (B) maintain a force  318  (e.g., a spring force) on the power protection device  118  in the direction towards the one or more electrical contact pads  204 (A) and  204 (B) when the power protection device  118  is removably received by the one or more clips  202 (A) and  202 (B) and cooperating one or more electrical contact pads  204 (A) and  204 (B). 
       FIG. 4A  illustrates a bottom view of the cover  114  and the power protection device  118  of the removable sensor module  102  illustrated in  FIG. 1 .  FIG. 4A  illustrates the cover  114  having a perimeter  402  and a wall  404  arranged around the perimeter  402 . The wall  404  may comprise an outside edge  406  arranged around the wall  404 . The wall  404  defining a case  408 . The case  408  having an overall inside length  410  of about 1.8 inches (45 millimeters) and an overall inside width  412  of about 0.9 inches (23 millimeters). The case  408  being configured to be arranged above a portion of the first planar surface  112 (A) to protect the first planar surface  112 (A), and not to be arranged above any portion of the second planar surface  112 (B). For example, the case  408  may be arranged above the current monitor  126 , capacitors, resistors, FETs, traces, and/or at least a portion of the one or more clips  202 (A) and  202 (B). However, no portion of the case  408  is arranged above the one or more unprotected power input and power output traces  310 (A) and  310 (B) arranged on top of the second planar surface  112 (B). 
     The cover  114  may comprise the receptacle  116  arranged in the wall  404  distal to the case  408 . The receptacle  116  may be arranged to contain the first end  110 (A) of the PCA  108 , and configured to removably receive at least a portion the power protection device  118 . For example, a portion of the gap  316  between the one or more clips  202 (A) and  202 (B) and cooperating one or more electrical contact pads  204 (A) and  204 (B) may be arranged in the receptacle  116 . The portion of the gap  316  arranged in the receptacle  116  may removably receive the power protection device  118 . For example the gap  316  may removably receive the one or more electrical portions  302 (A) and  302 (B) of the power protection device  118 . Further, the receptacle  116  may removably receive a portion the power protection device  118  up to, but not including, a gripping portion  414  of the power protection device  118 . 
     The cover  114  may include one or more vents  416 (A) and  416 (B) arranged in the wall  404  of the cover  114 . For example, the one or more vents  416 (A) and  416 (B) may be arranged along the long sides of the case  408 . For example, the one or more vents  416 (A) and  416 (B) may be arranged along the long sides of the case  408  substantially along the entire overall inside length  410  of the case  408 . When the removable sensor module  102  is inserted into a slot  106 , vertically relative to the power distribution system  104 , the one or more vents  416 (A) may be arranged at the bottom of the removable sensor module  102 , and the one or more vents  416 (B) may be arranged at the top of the removable sensor module. Thus, the one or more vents  416 (A) may draw cool ambient air into the cover  114  from the bottom of the power distribution system  104 , and the one or more vents  416 (B) may exhaust heated air out of the cover  114  to the top of the power distribution system  104 . The one or more vents  416 (B) may exhaust air heated by components (e.g., the current monitor  126 , capacitors, resistors, FETs, etc.) protected by the case  408 . 
     The cover  114  may comprise the rail  150  arranged on the wall  404  distal to the case  408 . For example, the rail  150  may be arrange perpendicular to the wall  404  of the case  408  and span the entire overall inside length  410  of the case  408  on one side of the case  408 . Further, the rail  150  may be arranged perpendicular to the wall  404  of the case  408  opposite the latch  148 . The rail  150  may provide for guiding the device into and/or out of the power distribution system  104 . 
     The cover  114  may be formed of a single unit of material. For example, the case  408 , the receptacle  116 , the rail  150 , and the latch  148  may all be formed of a single unit of plastic. The cover  114  may be formed of a single unit of plastic via a molding process (e.g., injection molding process, compression molding process, transfer molding process, etc.). Further, the cover  114  may be formed of a single unit of material via a machining process. 
       FIG. 4B  illustrates the one or more vents  416 (A) and  416 (B) may be arranged in a ceiling  418 , as well as the wall  404 , of the cover  114 . For example, each of the one or more vents  416 (A) and  416 (B) may extend through the wall  404  and through the ceiling  418  of the case  408 . 
       FIG. 4B  illustrates the rail  150  may comprise a flange  420  fixed perpendicularly to an edge  422 . The perpendicularly arranged flange  420  and edge  422  defining a substantially T-shaped cross-section of the rail  150 . 
       FIG. 4C  is a side view of the cover  114  and power protection device  118  of the removable sensor module  102  illustrated in  FIG. 1 .  FIG. 4C  illustrates the flange  420  of the rail  150  may have a width  424  of about 0.06 inches (2 millimeters), and the edge  422  may have a width  426  of about 0.02 inches (0.5 millimeters). The edge  422  and the flange  420  of the rail  150  may be slidably received by the gaps  158  and  162 , respectively, illustrated in detail view  156  of  FIG. 1 . 
       FIG. 4D  is a front view of the cover  114  and power protection device  118  of the removable sensor module  102  illustrated in  FIG. 1 .  FIG. 4D  illustrates the receptacle  116  may include a key  428 (A) to guide the power protection device  118  into the receptacle  116  when the power protection device  118  is removably inserted into the receptacle  116 . Similarly, the power protection device  118  may include a cooperating key  428 (B) to mate with the key  428 (A) in the receptacle  116 . The key  428 (A) and cooperating key  428 (B) may provide for preventing an improper installation of the power protection device  118 , and/or prevent installation of an improper power protection device. For example, the power protection device  118  may be a GMT “grasshopper” type fuse, having the cooperating key  428 (B) arranged on an outside surface of the GMT fuse. Similarly, the receptacle  116  may have the key  428 (A) arranged in an inside surface of the receptacle  116  configured to only removably receive the GMT fuse having the key  428 (B). In this way, the receptacle  116  may provide for preventing an improper installation (e.g., misaligned installation or wrong orientation) of the GMT fuse and/or prevent installation of an improper GMT fuse (improper sized GMT fuse or damaged GMT fuse). 
       FIG. 4D  illustrates an aperture  430  arranged in the wall  404  and distal to the case  408  to receive the light pipe  208 . The aperture  430  may be arranged between the receptacle  116  and the rail  150  to position the light pipe  208  to be visible to a user. 
       FIG. 5  illustrates another example implementation of a removable sensor module  502  for use in a power distribution system  504 . The removable sensor module  502  may be inserted as a single unit into an opening  506  of the power distribution system  504 . The opening  506  may have a width large enough to receive a plurality of removable sensor modules  502 . For example, the opening  506  may have a width  508  of about 5 inches (127 millimeters) and a height  510  of about 1.3 inches (33 millimeters). A card guide  512  may be fixed to a bottom inside surface of the power distribution system  504 . The card guide  512  may have at least about ten grooves  514  arranged along the width  508  of the power distribution system  504 . The grooves  514  may slidably receive the removable sensor modules  502  and guide the removable sensor modules  502  into the power distribution system  504  to blind-mate with an internal electrical component (e.g., a backplane) fixed in the power distribution system  504 . Thus, the opening  506  may removably receive at least about ten removable sensor modules  502 . The card guide  512  may be a single unit, or individual units, formed of a material (e.g., a plastic, a metal, a composite, etc.). 
       FIG. 6  illustrates another example implementation of a removable sensor module  602  for use in a power distribution system  604 . In this illustrated example, the power distribution system  604  includes grooves  606 , similar to grooves  152  illustrated in  FIG. 1 , arranged in the bottom surface  154  of the power distribution system  604 . As discussed above with regard to  FIG. 1 , the grooves  606  may be arranged to slidably receive the removable sensor modules  602 . Here, the power distribution system  604  includes the opening  506  discussed above with regard to  FIG. 5 , instead of the individual slots  106  illustrated in  FIG. 1 . 
     CONCLUSION 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claims.