Primary metering cabinet

Abstract

A primary metering cabinet includes a frame including a plurality of vertical frame members and a plurality of horizontal frame members, the frame defining an interior volume; a line connection located within the interior volume and coupled to the frame; a load connection located within the interior volume and coupled to the frame; a current transformer electrically coupled to the line connection and the load connection between the line connection and the load connection; and a carriage assembly coupled to the current transformer and mounted to the frame such that the current transformer is mounted to the frame via the carriage assembly. The current transformer and the carriage assembly are collectively movable relative to the frame between an installation position and a service position.

Description

Attorney Docket No. 201376-0119-WOOlPRIMARY METERING CABINETBACKGROUND

[0001] The present invention relates to primary metering cabinets. Primary metering cabinets are enclosures that house equipment used for measuring electrical energy on the primary (i.e. high-voltage) side of a power distribution system. In some embodiments, primary metering cabinets are used by utilities to measure and monitor electrical power consumption of commercial, industrial, and institutional customers that receive electricity from a high voltage distribution line.SUMMARY

[0002] In some aspects, the techniques described herein relate to a primary metering cabinet, including: a frame including a plurality of vertical frame members and a plurality of horizontal frame members, the frame defining an interior volume; a line connection located within the interior volume and insulated from the frame; a load connection located within the interior volume and insulated from the frame; a current transformer electrically coupled to the line connection and the load connection between the line connection and the load connection; and a carriage assembly coupled to the current transformer and mounted to the frame such that the current transformer is mounted to the frame via the carriage assembly, wherein the current transformer and the carriage assembly are collectively movable relative to the frame between an installation position and a service position.

[0003] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the carriage assembly is linearly slidable along the frame.

[0004] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the carriage assembly includes a first carriage mounted to a first horizontal member of the plurality of horizontal members and a second carriage mounted to a second horizontal member of the plurality of horizontal members, and wherein the first and second carriages are collectively slidable horizontally between the installation position and the service position.Attorney Docket No. 201376-0119-WOOl

[0005] In some aspects, the techniques described herein relate to a primary metering cabinet, further including a sliding rail, wherein the carriage assembly includes a T guide carriage movable along the sliding rail between the installation position and the service position.

[0006] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the carriage assembly includes a first bumper configured to engage the frame in the installation position and disengage the frame in the service position and a second bumper configured to engage the frame in the service position and disengage the frame in the installation position.

[0007] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the carriage assembly includes a lock movable between a locked position and an unlocked position, wherein, in the locked position, the lock prohibits movement of the carriage assembly relative to the frame.

[0008] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the carriage assembly includes a handle graspable by a user to move the current transformer between the installation position and the service position.

[0009] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the carriage assembly includes four carriages mounted to four horizontal members of the plurality of horizontal members.

[0010] In some aspects, the techniques described herein relate to a primary metering cabinet, further including a panel coupled to the frame via a plurality of thumb screws, the panel configured to cover a front side of the current transformer, wherein the panel is removable from the frame.

[0011] In some aspects, the techniques described herein relate to a primary metering cabinet, further including an enclosure at least partially surrounding the frame, the enclosure including a front access door providing access to the interior volume and a rear access door providing access to the interior volume, the rear access door located opposite the front access door such that the interior volume is located between the front and rear access doors, wherein the currentAttorney Docket No. 201376-0119-WOOl transformer is movable towards the rear access door from the installation position to the service position.

[0012] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein a front side of the current transformer is accessible via the front access door, and wherein a rear side of the current transformer is accessible via the rear access door.

[0013] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the frame includes a base mountable to a concrete pad.

[0014] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the current transformer is electrically and removably coupled to the line connection via a first metal plate and first bushing and wherein the current transformer is electrically and removably coupled to the load connection via a second metal plate and second bushing.

[0015] In some aspects, the techniques described herein relate to a primary metering cabinet, further including a signal line electrically coupled to the current transformer and extending from the current transformer to a junction box mounted relative to the frame when the current transformer is in the installed position and the service position.

[0016] In some aspects, the techniques described herein relate to a primary metering cabinet, wherein the line connection is a first line connection, the load connection is a first load connection, and the current transformer is a first current transformer, the primary metering cabinet further including: a second line connection and a third line connection; a second load connection and a third load connection; a second current transformer electrically coupled to the second line connection and the second load connection between the second line connection and the second load connection; and a third current transformer electrically coupled to the third line connection and the third load connection between the third line connection and the third load connection; wherein the first current transformer, the second current transformer, the third current transformer, and the carriage assembly are collectively movable relative to the frame between the installation position and the service position.Attorney Docket No. 201376-0119-WOOl

[0017] In some aspects, the techniques described herein relate to a method, the method including: accessing the interior volume of the frame; disconnecting the current transformer from the line connection; disconnecting the current transformer from the load connection; and translating the carriage assembly from the installation position to the service position.

[0018] In some aspects, the techniques described herein relate to a primary metering cabinet, including: a frame including a plurality of vertical frame members and a plurality of horizontal frame members, the frame defining an interior volume; a first sliding rail and a second sliding rail coupled to a first horizontal member and a second horizontal member, respectively, of the plurality of horizontal members, and a first carriage and a second carriage linearly slidable along the first sliding rail and the second sliding rail, respectively, wherein the first and second carriages are configured to support a current transformer and are collectively movable relative to the frame between an installation position and a service position.

[0019] In some aspects, the techniques described herein relate to a primary metering cabinet, further including a first bumper configured to engage the frame in the installation position and disengage the frame in the service position and a second bumper configured to engage the frame in the service position and disengage the frame in the installation position.

[0020] In some aspects, the techniques described herein relate to a primary metering cabinet, further including a lock movable between a locked position and an unlocked position, wherein, in the locked position, the lock prohibits movement of the first carriage relative to the frame.

[0021] In some aspects, the techniques described herein relate to a primary metering cabinet, further including a panel coupled to the frame via a plurality of thumb screws, wherein the panel is removable from the frame to provide access to the interior volume.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Fig. l is a rear perspective view of a primary metering cabinet showing an enclosure with a rear access door.

[0023] Fig. 2 is a front perspective view of the primary metering cabinet of Fig. 1, showing a front access door of the enclosure in an open position.Attorney Docket No. 201376-0119-WOOl

[0024] Fig. 3 is a front perspective view of the frame, removable panels, and line and load connectors that are located within the enclosure of the primary metering cabinet of Fig. 1 .

[0025] Fig. 4 is a front perspective view of the frame of Fig. 3 with the removable panels shown spaced apart from the frame.

[0026] Fig. 5 is a rear perspective view of the primary metering cabinet of Fig. 1 with the enclosure removed to show the internals of the cabinet.

[0027] Fig. 6 is a cross-sectional view of the primary metering cabinet of Fig. 1 with the enclosure removed.

[0028] Fig. 7 is a rear perspective view of a carriage assembly and current transformers of the primary metering cabinet of Fig. 1 in an installation position.

[0029] Fig. 8 is a rear perspective view of the carriage assembly and current transformers of the primary metering cabinet of Fig. 1 in a service position.

[0030] Fig. 9 is a rear perspective view of the primary metering cabinet of Fig. 1 with the rear access door removed for clarity.

[0031] Fig. 10 is an enlarged perspective view the carriage assembly of the primary metering cabinet of Fig. 1.

[0032] Fig. 11 is a perspective view of signal lines between a junction box and current and voltage transformers of the primary metering cabinet of Fig. 1.

[0033] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.DETAILED DESCRIPTIONAttorney Docket No. 201376-0119-WOOl

[0034] With reference to Figs. 1-3, a primary metering cabinet 100 includes a frame 104 (Fig. 3) formed of a plurality of horizontal frame members 108 and vertical frame members 1 12 connected to one another to form a three-dimensional structure (as shown, a rectangular structure) defining an interior volume 116 therein. An enclosure 120 surrounds at least a portion of the frame 104. As shown in Figs. 1-2, the enclosure 120 includes front, rear, left, right, and top panels that correspond to and extend around a front side 104A of the frame 104 (Fig. 2), a rear side 104B of the frame (Fig. 1), left and right sides of the frame 104, and a top side of the frame 104. The enclosure includes a front access door 124 (Fig. 2) that is openable to provide access to the front side 104A of the frame 104 and a rear access door 128 (Fig 1) that is openable to provide access to the rear side 104B of the frame 104. Each door 124, 128 is generally similar in size, shape and operation and may be lockable to prevent unwanted access to high voltage equipment mounted within the interior volume 116 of the frame 104.

[0035] The frame 104 and enclosure 120 are mountable to and supported by a concrete pad 132. As shown in Fig. 6, the concrete pad 132 includes openings 136 extending vertically through the pad 132 as an access point for high-voltage lines to enter the interior volume 116 of the frame 104. The frame 104 is therefore fully enclosed within the enclosure 120 and the concrete pad 132 when the access doors 124, 128 are closed. The access doors 124, 128 are openable to provide access to the frame 112 for service and monitoring purposes.

[0036] With reference to Fig. 3, the frame 104 includes four vertical frame members 112 extending vertically upward from the concrete pad 132. Horizontal frame members 108 extend perpendicular to the vertical frame members 112 and extend between adjacent vertical frame members 112 to form a generally rectangular structure. In some embodiments, the frame 104 is approximately 76.5 inches (1.94 meters) in height, 44.5 inches (1.13 meters) in width, and 31 inches (0.78 meters) in depth, with the enclosure 120 being larger in each dimension to extend around the front, rear, top, and two sides of the frame 104.

[0037] Four horizontal frame members 108 collectively form a base 140 (i.e., a rectangular base) at a lower end of the frame 104. The base 140 contacts the concrete pad 132 and is fastened to the concrete pad (e.g., via threaded fasteners). A similar arrangement of horizontal frame members 108 adjacent the top of the vertical members defines a top end 144 of the frameAttorney Docket No. 201376-0119-WOOl104. Additional horizontal frame members 108 extend along the front, rear, left, and right sides of the frame 104 at various heights between the base 140 and top end 144 of the frame 104 to provide additional stability and mounting locations for various elements, such as sliding rails 208 and removable panels 148.

[0038] As shown in Figs. 3-4, removable panels 148 are coupled to the frame 104 at various heights to cover and preclude access to the interior volume 116 of the frame 104. At least some of the removable panels 148 (as shown, the panels 148 that are not directly coupled to the line connections 156 and load connections 160) are coupled to the frame 104 via thumb screws 152. The thumb screws 152 are toolless, allowing a user to attach and remove panels 148 from the frame 104 without a tool. By removing panels 148, a service technician is able to access the interior volume 116 of the frame 104 via the front access door 124.

[0039] The primary metering cabinet 100 houses equipment used for measuring electrical energy on the primary (i.e. high-voltage) side of a power distribution system within the interior volume 116 of the frame 104. In a non-exhaustive list, the equipment includes line connections 156, load connections 160, current transformers 164, and first and second metal plates 168, 172.

[0040] Line connections 156 connect the incoming high-voltage power distribution lines (i.e., the lines that enter the cabinet 100 via the openings 136 within the concrete pad 132) to the current transformers 164. The line connections 156 are designed to handle high voltages and currents and, in some embodiments, are made of conductive materials such as copper or aluminum. The line connections 156 are located (at least partially) within the interior volume 116, are insulated from the frame 104 (e.g., via an insulating bushing and / or coating) and are mechanically (e.g., indirectly) coupled to the frame 104. In some embodiments, the line connections 156 are each defined at least partially via a bushing (e.g., an apparatus to air bushing) that electrically insulates the connection 156 from the frame 104. As shown, the primary metering cabinet 100 supports three-phase power and therefore includes three line connections 156. The three line connections 156 are connected to respective current transformers 164 via respective first metal plates 168 and fasteners 176. The current transformers 164 step down and measure the current flowing through the respective line connection 156 (from the high-voltage power distribution line). By measuring the current, theAttorney Docket No. 201376-0119-WOOl current transformers 164 provide monitoring and control of the electrical power distribution system.

[0041] Each current transformer 164 is coupled to a respective load connection 160 via a respective second metal plate 172 and fastener 180. The load connections 160 are the points where the electrical power is delivered from the monitoring equipment (i.e., current transformers 164) to downstream electrical equipment (e.g., a customer’s equipment, a distribution network) outside of the cabinet 100. The load connections 160 are located (at least partially) within the interior volume 116, are insulated from the frame 104 (e.g., via an insulating bushing and / or coating) and are mechanically (e.g., indirectly) coupled to the frame 104. In some embodiments, the load connections 160 are each defined at least partially via a bushing (e.g., an apparatus to air bushing) that electrically insulates the connection 160 from the frame 104. The power lines from the load connections 160 may similarly pass through the openings 136 in the concrete pad 132. Dead end connectors (not shown) may be coupled to the terminals 156, 160 to facilitate a physical connection to the power lines into and out of the cabinet 100.

[0042] Additional elements are located within the interior volume 116 of the cabinet 100. Divider panels 184 extend between and separate the first line and load connections 156, 160 and current transformers 164 from the second line and load connections 156, 160 and current transformers 164 and separate the second line and load connections 156, 160 and current transformers 164 from the third line and load connections 156, 160 and current transformers 164. In some embodiments, the panels 148, 184 are made of a thermoset fiberglass-reinforced polyester insulating product. Voltage transformers 188 are located within the interior volume 116 and are connected to respective line connections 156 via third metal plates 192. The third metal plates 192 are connected to the first metal plates 168 via the fasteners 176.

[0043] In the embodiment shown in Figs. 5-6, the voltage transformers 188 are mounted to the base 140. The line connections 156 are located vertically above the voltage transformers 188. The current transformers 164 are located vertically above the line connections 156. The load connections 160 are located vertically above the current transformers 164.

[0044] Accessing the current transformers 164 for servicing provides a challenge as many components are housed within a relatively compact frame 112 (defining a relatively compactAttorney Docket No. 201376-0119-WOOl interior volume 116) and it is desirable to decrease the size of the cabinet 100 for space savings and cost savings. The front access door 124 of the enclosure 120 and removable panels 148 provide access to a forward side of the current transformers 164, though the remaining sides of the transformers and access to remove a current transformer 164 are generally precluded via the front access door 124. The rear access door 128 provides access to the interior volume 116 of the frame 104 and the rear of the current transformers 164, though the current transformers 164 are provided nearer to the front of the frame 112. As such, the cabinet 100 is equipped with a carriage assembly 200 configured to move the current transformers 164 from their installation position (Fig. 7) adjacent the front of the cabinet 100 to a service position (Fig. 8) adjacent the rear of the cabinet 100.

[0045] The carriage assembly 200 includes a plurality of carriages 204 that move along sliding rails 208. As shown, the carriage assembly 200 includes four carriages 204, two upper carriages and two lower carriages, with an upper and lower carriage mounted on each of the left and right sides of the frame 112. More particularly, four sliding rails 208 are located on four horizontal frame members 108, each of the sliding rails 208 supporting one of the carriages 204. In the embodiment shown, the sliding rails 208 are T guide rails formed as a T-shaped extrusion and the carriages including a mating T-shaped recess 212 that receives the rail 208. In other embodiments, the interface between the sliding rail 208 and carriage 204 may be dissimilar (e.g., an alternative cross-sectional profile, a recess formed in the rail 208 that receives a protrusion of the carriage 204, etc.) to the illustrated embodiment.

[0046] Each of the carriages 204 is coupled to a mounting plate 216, with the two upper carriages 204 attached to opposing upper corners of the mounting plate 216 and the two lower carriages 204 attached to opposing lower corners of the mounting plate 216. The mounting plate 216 spans the width of the frame 112 (between adjacent vertical frame members 112) and supports the three current transformers 164 thereon. Written another way, the current transformers 164 are coupled to the frame 112 via the mounting plate 216 and carriage assembly 200. Each current transformer 164 is coupled to the mounting plate 216 via a plurality of fasteners 220.Attorney Docket No. 201376-0119-WOOl

[0047] The carriages 204 are collectively movable (e.g., linearly slidable) along the length of the rails 208 with the mounting plate 216 and current transformers 164. By sliding the carriages 204 along the sliding rails 208, the current transformers 164 are movable towards the rear of the frame 104 and nearer the rear access door 128, facilitating easier maintenance and monitoring of the current transformers 164. As shown in Fig. 10, A handle 224 is mounted to a rear side of the mounting plate 216 and is graspable by a user (e.g., service technician) to pull the mounting plate 216 (and carriage assembly 200 and current transformers 164) from the installation position towards the rear access door 128 to the service position. The user can also grasp the handle when sliding the current transformers 164 back to the installation position.

[0048] A lock 228 is coupled to one or more of the carriages 204 and can be switched between a locked position and an unlocked position to selectively prohibit movement of the carriages 204. As shown in Fig. 10, the lock 228 includes a handle that is rotatable (e.g. by a user’s hand) between the locked position and the unlocked position. In some embodiments, the lock includes a locking element (not shown) that extends into an opening in the rail 208 and or the frame 104 or otherwise into engagement with the rail 208 to increase the friction between the carriage 204 and the rail 208. In some embodiments, only one or two of the carriages 204 (e.g., the upper carriages) include a lock 228. In other embodiments, every carriage 204 includes a lock 228. As the sliding rails 208 extend parallel to one another and the carriages 204 are connected to one another via the mounting plate 216, locking a single lock 228 precludes movement of any of the carriages 204. In some embodiments, the lock 228 is lockable in the installation position and the service position. In some embodiments, the lock 228 is further lockable at a plurality (e.g., multiple distinct, at any location) of positions between the installation position and the service position.

[0049] As shown in Fig. 8, a first bumper 232 extends perpendicularly from the mounting plate 216 towards a forward vertical frame member 112. When the current transformers 164 are located in the installation position, the first bumper 232 engages an inside surface of the forward vertical frame member 112. The first bumper 232 functions as a stop to prevent movement of the carriage assembly 200 and current transformers 164 forward beyond the installation position. With reference to Figs. 8 and 10, a second bumper 236 extends parallel to the first bumper 232, though from a rear side of the mounting plate 216 towards a rear vertical frame member 112.Attorney Docket No. 201376-0119-WOOlWhen the current transformers 164 are located in the service position, the second bumper 236 engages an inside surface of the rear vertical frame member 112. The second bumper 236 functions as a stop to prevent movement of the carriage assembly 200 and current transformers 164 rearward beyond the service position.

[0050] Two of the first bumpers 232 are shown in Fig. 8 for engaging each of the forward vertical frame members 112. Similarly, two of the second bumpers 236 engage each of the rear vertical frame members 112. When the carriage assembly 200 and current transformers 164 are moved away from the installation position, the first bumpers 232 are moved out of engagement with the frame 104. Similarly, when the carriage assembly 200 and current transformers 164 are moved away from the service position, the second bumpers 236 are moved out of engagement with (i.e., disengage) the frame 104. In some embodiments, a distal end of the first and second bumpers 232, 236 includes a dampening material (e.g., rubber) for engaging the frame 104.

[0051] With reference to Fig. 11, a junction box 240 is mounted relative to the frame 104 (i.e., not movable relative to the frame 104). In some embodiments, the junction box 240 is mounted to the frame 104. In other embodiments, the junction box 240 is mounted to the enclosure 120. Signal lines 244, 248 extend from the current transformers 164 and voltage transformers 188 and into the junction box 240. The voltage transformers 188 are fixed relative to the frame 104 and are therefore fixed relative to the junction box 240 and the signal line 248 is therefore sized to reach from the voltage transformers 188 to the junction box 240. The current transformers 164 are movable relative to the frame 104 between the installation position and the service position and are therefore movable relative to the junction box 240. The signal line 244 from the current transformers 164 to the signal box has an increased length to include slack so that the current transformers 164 are movable between the installation and service positions without disconnecting the signal line 244.

[0052] In operation, to service the current transformers 164 and move the current transformers 164 from the installation position to the service position, a user (e.g., service technician) completes safety checks as necessary and opens the rear access door 128, providing access to the interior volume 116 of the frame 104, as shown in Fig. 9 (the rear access door 128 removed for clarity). In some embodiments, components within the frame 104, such as theAttorney Docket No. 201376-0119-WOOl divider panels 184, and / or portions of the frame 104, such as horizontal frame members 108 extending between the rear vertical frame members 1 12 are removed to provide access to the current transformers 164. For each current transformer 164, the first and second metal plates 168, 172 are disconnected from the line and load connections 156, 160, respectively, by removing the fasteners 176, 180. If the carriage assembly 200 is locked in the installation position, the lock 228 is unlocked. The user engages the handle 224 and linearly slides (i.e., translates) the carriages 204 along their respective rails 208, sliding the current transformers 164 rearward from the installation position to the service position until the second bumpers 236 engage the frame 104. The carriage assembly 200 may be locked in the service position to prevent unwanted movement along the rails 208 when servicing the current transformers 164.

[0053] When service is complete, the user disengages / unlocks the lock 228 and the user pushes the carriage assembly 200 and current transformers 164 forward until the first bumpers 232 engage the frame 104 and the current transformers 164 are returned to the installation position. The lock 228 is reengaged to maintain the position of the current transformers 164 and the first and second metal plates 168, 172 are reconnected to the line and load connections 156, 160 via the fasteners 176, 180. Any components (e.g., divider panels 184) removed from the cabinet 100 are replaced and the rear access door 128 is closed and locked.

[0054] Various features and advantages of the invention are set forth in the following claims.

Claims

Attorney Docket No. 201376-0119-WOOlCLAIMSWhat is claimed is:

1. A primary metering cabinet, comprising: a frame including a plurality of vertical frame members and a plurality of horizontal frame members, the frame defining an interior volume; a line connection located within the interior volume and insulated from the frame; a load connection located within the interior volume and insulated from the frame; a current transformer electrically coupled to the line connection and the load connection between the line connection and the load connection; and a carriage assembly coupled to the current transformer and mounted to the frame such that the current transformer is mounted to the frame via the carriage assembly, wherein the current transformer and the carriage assembly are collectively movable relative to the frame between an installation position and a service position.

2. The primary metering cabinet of claim 1, wherein the carriage assembly is linearly slidable along the frame.

3. The primary metering cabinet of claim 2, wherein the carriage assembly includes a first carriage mounted to a first horizontal frame member of the plurality of horizontal frame members and a second carriage mounted to a second horizontal frame member of the plurality of horizontal frame members, and wherein the first and second carriages are collectively slidable horizontally between the installation position and the service position.

4. The primary metering cabinet of claim 1, further comprising a sliding rail, wherein the carriage assembly includes a T guide carriage movable along the sliding rail between the installation position and the service position.

5. The primary metering cabinet of claim 1, wherein the carriage assembly includes a first bumper configured to engage the frame in the installation position and disengage the frame in theAttorney Docket No. 201376-0119-WOOl service position and a second bumper configured to engage the frame in the service position and disengage the frame in the installation position.

6. The primary metering cabinet of claim 1, wherein the carriage assembly includes a lock movable between a locked position and an unlocked position, wherein, in the locked position, the lock prohibits movement of the carriage assembly relative to the frame.

7. The primary metering cabinet of claim 1, wherein the carriage assembly includes a handle graspable by a user to move the current transformer between the installation position and the service position.

8. The primary metering cabinet of claim 1, wherein the carriage assembly includes four carriages mounted to four horizontal members of the plurality of horizontal frame members.

9. The primary metering cabinet of claim 1, further comprising a panel coupled to the frame via a plurality of thumb screws, the panel configured to cover a front side of the current transformer, wherein the panel is removable from the frame.

10. The primary metering cabinet of claim 1, further comprising an enclosure at least partially surrounding the frame, the enclosure including a front access door providing access to the interior volume and a rear access door providing access to the interior volume, the rear access door located opposite the front access door such that the interior volume is located between the front and rear access doors, wherein the current transformer is movable towards the rear access door from the installation position to the service position.

11. The primary metering cabinet of claim 10, wherein a front side of the current transformer is accessible via the front access door, and wherein a rear side of the current transformer is accessible via the rear access door.

12. The primary metering cabinet of claim 1, wherein the frame includes a base mountable to a concrete pad.Attorney Docket No. 201376-0119-WOOl13. The primary metering cabinet of claim 1, wherein the current transformer is electrically and removably coupled to the line connection via a first metal plate and first bushing and wherein the current transformer is electrically and removably coupled to the load connection via a second metal plate and second bushing.

14. The primary metering cabinet of claim 1, further comprising a signal line electrically coupled to the current transformer and extending from the current transformer to a junction box mounted relative to the frame when the current transformer is in the installation position and the service position.

15. The primary metering cabinet of claim 1, wherein the line connection is a first line connection, the load connection is a first load connection, and the current transformer is a first current transformer, the primary metering cabinet further comprising: a second line connection and a third line connection; a second load connection and a third load connection; a second current transformer electrically coupled to the second line connection and the second load connection between the second line connection and the second load connection; and a third current transformer electrically coupled to the third line connection and the third load connection between the third line connection and the third load connection; wherein the first current transformer, the second current transformer, the third current transformer, and the carriage assembly are collectively movable relative to the frame between the installation position and the service position.

16. A method of servicing the primary metering cabinet of claim 1, the method comprising: accessing the interior volume of the frame; disconnecting the current transformer from the line connection; disconnecting the current transformer from the load connection; and translating the carriage assembly from the installation position to the service position.Attorney Docket No. 201376-0119-WOOl17. A primary metering cabinet, comprising: a frame including a plurality of vertical frame members and a plurality of horizontal frame members, the frame defining an interior volume; a first sliding rail and a second sliding rail coupled to a first horizontal member and a second horizontal member, respectively, of the plurality of horizontal frame members, and a first carriage and a second carriage linearly slidable along the first sliding rail and the second sliding rail, respectively, wherein the first and second carriages are configured to support a current transformer and are collectively movable relative to the frame between an installation position and a service position.

18. The primary metering cabinet of claim 17, further comprising a first bumper configured to engage the frame in the installation position and disengage the frame in the service position and a second bumper configured to engage the frame in the service position and disengage the frame in the installation position.

19. The primary metering cabinet of claim 17, further comprising a lock movable between a locked position and an unlocked position, wherein, in the locked position, the lock prohibits movement of the first carriage relative to the frame.

20. The primary metering cabinet of claim 17, further comprising a panel coupled to the frame via a plurality of thumb screws, wherein the panel is removable from the frame to provide access to the interior volume.

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