Seamless slide plate for outdoor enclosure

Abstract

An outdoor enclosure defines an internal cavity for receiving an electrical cable and for protecting wiring connections from adverse environmental conditions, such as water from rain, sleet, melting snow, or melting ice. The enclosure includes a housing having a back wall, a pair of side walls, a floor, and a top wall that together define an opening for providing access to the internal cavity. A slide plate is removably attached to the housing and extends continuously at least the entire width of the opening. The enclosure further includes a door attached to the housing that is movable between a closed position covering the opening and an opened position to expose the internal cavity. The slide plate is positioned between the top wall of the housing and the door and defines at least one passageway with the top wall for permitting passage of the electrical cable from an initial enclosure to a subsequent enclosure vertically stacked on the initial enclosure. In a preferred embodiment, the slide plate comprises a first flange depending downwardly from the top wall and a second flange extending outwardly from the first flange that directs the water away from the opening of the housing.

Description

CROSS REFERENCE TO RELATED APPLICATIONS (none)

FIELD OF THE INVENTION

[0001] The present invention relates generally to outdoor enclosures for electrical distribution network cables and wiring connections. More particularly, the invention is a seamless slide plate that extends across the entire width of the opening of an outdoor enclosure to provide for vertical expansion and for improved weatherability and access to the electrical cables and wiring connections in the event that the enclosure must be replaced.

BACKGROUND OF THE INVENTION

[0002] Outdoor enclosures for electrical distribution networks are exposed to various environmental conditions, and in particular, to water from rain, sleet, melting snow, or melting ice. Due to the need to expand subscriber service over time, service providers prefer to use outdoor enclosures that provide for future expansion. As a result of wiring density concerns, vertical expansion, or “stackability,” is the most desirable feature for providing future expansion. Stackability, as used herein, refers to the capability to position a subsequent enclosure on top of a previously installed enclosure and to route the existing service cable and wiring between the initial and subsequent enclosures. For example, a service provider may desire to route a 100 pair telephone cable into the initial enclosure and to drop-off only 50 pair for connection to existing subscriber drop lines. Later, the service provider may desire to route the remaining 50 pair of the 100 pair telephone cable into a subsequent enclosure for connection to additional subscriber drop lines.

[0003] Satisfying the stackability requirement, however, requires that at least one, and preferably two, holes are formed in the top of the enclosure to route the service cable and any additional wiring from the initial enclosure into the subsequent enclosure. Obviously, the presence of a hole in the top of the enclosure creates the possibility that water from rain, sleet, melting snow, or melting ice may enter the enclosure and cause a short of the wiring or electrical components housed inside the enclosure. Consequently, the majority of outdoor enclosures do not provide for vertical expansion. In instances where stackability is required, the top of the enclosure is typically provided with one or more conduit knockouts. Once removed, the knockouts permit the service cable and wiring to be routed between the two enclosures. Knockouts, however, present at least two problems. First, it is difficult to permit easy removal of the knockout while at the same time properly sealing the knockout against environmental conditions. Second, once the service cable is passed through the knockout and the wiring is connected, the housing of the initial enclosure cannot be replaced without cutting the service cable or without first disconnecting and then reconnecting the wiring adjacent the knockout. In either case, service to the additional subscribers must be disrupted temporarily.

[0004] To avoid the difficulties presented by conduit knockouts, it is known to provide one or more slide plates at the top of the enclosure. As illustrated in FIG. 1, the top of the housing 11 of a prior art outdoor enclosure 10 is typically provided with a first slide plate 12 for the cable from the service provider to pass through and a second slide plate 14 for the wiring connections to pass through. When not in use, the slide plates 12, 14 are typically covered by a conventional rain cap 13 removably attached to the top of the housing 11 of the enclosure 10. The slide plates 12, 14, however, create discontinuities in the horizontal rain channel 16 adjacent the opening 15 of the housing 11. The discontinuities, which are in the form of a vertical seam 17 on each side of the slide plates 12, 14, permit water to accumulate in the rain channel 16 and to seep through the vertical seam 17 into the enclosure 10. The discontinuities are typically sealed with a non-porous, non-conductive, sealant of the type commonly used in electrical applications, one example of which is sold under the trade name “B-Sealant” and is commercially available from Communications Technology Corporation. The sealant is initially placed along each vertical seam 17 between the slide plate 12, 14 and the rain channel 16. However, the sealant must be reapplied each time the slide plates 12, 14 are removed to access the service cable or wiring connections inside the enclosure 10. For various reasons, the craftsperson working in the field oftentimes fails to reapply the sealant to seams 17 before reinstalling the slide plates 12, 14. As a result, the enclosure 10 is susceptible to damage from exposure to adverse environmental conditions, and in particular, to water from rain, sleet, melting snow, or melting ice.

BRIEF SUMMARY OF THE INVENTION

[0005] Accordingly, it is apparent that a need exists for an outdoor enclosure that provides for vertical expansion. A further need exists for an outdoor enclosure that provides improved weatherability and access to the electrical cables and wiring connections inside the enclosure in the event that the enclosure must be replaced. Additional features and advantages of the invention will be set forth in the following description, and, in part, will become apparent from the description, or may be discerned by practice of the invention. These objectives and other advantages of the invention will be realized and attained by an outdoor enclosure having the seamless slide plate particularly pointed out in the written description and accompanying drawings provided herein, along with the claims appended hereto.

[0006] To achieve these and other advantages, and in accordance with the purpose of the invention as embodied and broadly described herein, the present invention is directed to an outdoor enclosure defining an internal cavity for receiving an electrical cable and for protecting wiring connections within the internal cavity from exposure to adverse environmental conditions, such as water from rain, sleet, melting snow, or melting ice. The enclosure includes a housing having an opening for providing sufficient access to the internal cavity. A seamless slide plate is removably attached to the housing. The slide plate extends at least the entire width of the opening of the housing and directs the water around the opening of the housing and away from the internal cavity defined by the enclosure.

[0007] In a preferred embodiment, the housing has a back wall, a pair of side walls depending outwardly from the back wall, a floor depending outwardly from the back wall and extending between the side walls, and a top wall opposite the floor depending outwardly from the back wall and extending between the side walls. Together, the back wall, side walls, floor, and top wall define the opening of the housing. Preferably, the enclosure further includes a door attached to the housing. The door is movable between a closed position covering the opening of the housing and an opened position exposing and providing access to the internal cavity defined by the enclosure. In a preferred embodiment of the invention, the door is hingedly attached to the housing adjacent one of the side walls.

[0008] In another aspect of the invention, the slide plate is positioned between the top wall of the housing and the door. The top wall of the housing depends outwardly from the back wall of the housing along a portion of the side walls and a top portion of the slide plate extends inwardly in the direction of the back wall of the housing along the remaining portion of the side walls. The slide plate defines at least one passageway with the top wall for permitting the electrical cable to pass therethrough. The slide plate includes channeling means extending continuously at least the entire width of the opening of the housing for preventing water from entering the internal cavity defined by the enclosure. In a preferred embodiment, the channeling means of the slide plate includes a first flange depending downwardly from the top wall, and a second flange extending outwardly from the first flange adjacent the opening of the housing.

[0009] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary and are intended to provide further explanation of the invention as claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate one or several embodiments of the invention, and, together with the written description, serve to better explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] One or more preferred embodiments of the invention will be described more fully below and illustrated in the accompanying drawings in which:

[0011] FIG. 1 is an exploded perspective view of a prior art outdoor enclosure including a pair of removable slide plates for providing vertical expansion and limited weatherability and access to the electrical cable and wiring connections inside the enclosure;

[0012] FIG. 2 is an exploded perspective view of an outdoor enclosure including a seamless slide plate according to the present invention for providing vertical expansion and improved weatherability and access to the electrical cable and wiring connections inside the enclosure;

[0013] FIG. 3 is a top plan view of the slide plate of FIG. 2;

[0014] FIG. 4 is an end elevation view of the slide plate of FIG. 2; and

[0015] FIG. 5 is a detail sectional view of a portion of the outdoor enclosure of FIG. 2 shown with the door of the housing in the closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Referring now to the accompanying drawings, in which one or more preferred embodiments of the invention are illustrated, FIGS. 2-5 show a preferred embodiment of an outdoor enclosure, indicated generally at 20, according to the invention. The outdoor enclosure 20 defines an internal cavity 22 that is suitable for receiving an electrical distribution cable 21 and for protecting wiring connections 23 and any electrical components (not shown) within the internal cavity 22 from adverse environmental conditions, such as water from rain, sleet, melting snow, or melting ice. As best shown in FIG. 2, outdoor enclosure 20 comprises a housing 30 defining an opening 40 and a slide plate 50 that extends continuously at least the entire width of the opening 40. As a result, the outdoor enclosure 20 provides for vertical expansion and improved weatherability and access to the electrical cable 21 and wiring connections 23 within the internal cavity 22, as will be described.

[0017] As shown in FIG. 2, the housing 30 is a generally rectangular box having height and width dimensions and a depth dimension that is typically less than the height and width dimensions. The housing 30, however, may have any shape and may be any size suitable to accommodate the electrical cable 21 and wiring connections 23, as well as any additional electrical components required for a particular application, within the internal cavity 22 of the enclosure 20. The housing 30 may be made of any suitable structural material, but preferably is made of thin sheet metal or a strong, durable plastic. The housing 30 comprises a generally planar back wall 32 opposite the opening 40. The back wall 32 is typically provided with a plurality of through holes 31 (two shown) that receive conventional fasteners, such as nails or screws, to affix the housing 30 to a structural component of the distribution network, such as an exterior wall of a building. A pair of generally planar side walls 34 depend outwardly from the back wall 32. The side walls 34 are preferably parallel and extend perpendicular from the back wall 32. The side walls 34 each comprise an inwardly extending flange 33 having at least one hole 35 for receiving a conventional fastener, such as a sheet metal screw, to removably attach the slide plate 50 to the housing 30. The side walls 34 may further comprise inwardly extending flanges 62 having holes 61 for receiving fasteners or drop posts therein to removably attach a rain cap 60 to the housing 30, as will be described.

[0018] The housing 30 further comprises a generally planar floor 36 that depends outwardly from the back wall 32 and extends laterally between the side walls 34. The floor 36 has at least one through hole 37 for routing the incoming distribution service cable 21 into the internal cavity 22 defined by the enclosure 20. A seal (not shown) is typically provided between the hole 37 and service cable 21 to prevent adverse elements, such as dust, dirt, and insect or rodent infestations, from entering the enclosure 20, and thereby degrading the performance of the distribution network. The floor 36 typically has a second through hole (not shown) for routing the outgoing distribution drop cable 25 out of the enclosure 20. The second through hole and the drop cable 25 are sealed by a separate seal in the same or a different manner as the hole 37 and the service cable 21. The housing 30 further comprises a generally planar top wall 38 that depends outwardly from the back wall 32 and extends laterally between the side walls 34 opposite the floor 36. Like the flanges 62 of side walls 34, the top wall 38 may also have one or more holes 61 for receiving fasteners or drop posts therein to removably attach the rain cap 60 to the housing 30.

[0019] As shown in FIG. 2, the top wall 38 depends outwardly from the back wall 32 along only a portion of the flanges 62 of the side walls 34. When the slide plate 50 is attached to the flanges 33 of the side walls 34, a top portion 52 of the slide plate 50 extends inwardly along the remaining portion of the flanges 62 of the side walls 34. Thus, the top wall 38 and the inner edge 53 of the top portion 52 of the slide plate 50 adjoin one another in a tight butt-joint arrangement. The inner edge 53 of the slide plate 50 and the top wall 38 of the housing 30 are contoured to define at least one, and preferably two, through holes 39. The holes 39 are provided to permit the distribution cable 21 and the wiring connections 23 to pass from the interior cavity 22 of the enclosure 20 into the interior cavity of a subsequent enclosure vertically stacked on top of the enclosure 20, as will be described. The holes 39 need not be identical in size or shape, and typically as shown herein, the hole 39 that routes the distribution cable 21 into the subsequent enclosure is slightly larger in cross sectional area. Slide plate 50 may also be provided with cutouts or through holes 51 on top portion 52 that align with holes 61 provided on flanges 62 of side walls 34. Holes 51 are sized to permit fasteners or drop posts to pass therethrough to removably attach rain cap 60 to housing 30.

[0020] Together, the back wall 32, the side walls 34, the floor 36, and the top wall 38 define the opening 40 of the housing 30. The opening 40 is typically covered by a door 42 that is attached to at least one of the side walls 34 of the housing 30. The door 42 is movable between a closed position covering the opening 40 defined by the housing 30 and an opened position exposing the opening 40 and the internal cavity 22 defined by the enclosure 20. In the opened position, the door 42 provides access to the distribution cable 21, the wiring connections 23, and any electrical components within the internal cavity 22 of the enclosure 20. As shown in FIG. 2, the door 42 preferably is hinged to a side wall 34 of the housing 30 by a conventional pin hinge 44 that has one half affixed to the flange 33 of the side wall 34 and the other half affixed to an inner edge 41 of the door 42. Housing 30, however, need not comprise movable door 42 and instead may comprise a front wall (not shown) opposite the back wall 32 covering a portion of opening 40 with the removable slide plate 50 covering the remaining portion of the opening 40. In such a configuration, the slide plate 50 may extend downwardly in the direction of the floor 36 to, for example, about the middle of the side walls 34 to provide sufficient access to the distribution cable 21, the wiring connections 23 and any electrical components within the interior cavity 22 of the enclosure 20. The housing 30 may further comprise a latch 46 and a lock (not shown) for securing the door 42 to the housing, and thereby limiting access to the internal cavity 22 of the enclosure 20 to authorized personnel.

[0021] As best shown in FIGS. 3 and 4, the slide plate 50 further comprises channeling means 54 for preventing water, such as from rain, sleet, melting snow, or melting ice, from entering the internal cavity 22 defined by the enclosure 20, and thereby degrading the performance of the distribution network. In the preferred embodiment described and illustrated herein, the channeling means 54 comprises a downwardly extending first flange 56 and an outwardly extending second flange 57. At least one, and preferably two, through holes 55 (FIG. 2) are provided in first flange 56 for receiving the fasteners that removably attach the slide plate 50 to the housing 30, as previously described. Second flange 57 extends outwardly from the lower edge of flange 56 in a direction away from internal cavity 22 and opening 40. Preferably, channeling means 54 of slide plate 50 further comprises a lip 58 extending upwardly a short distance from the outer edge of second flange 57. Lip 58 prevents water collected on second flange 57 from flowing downwardly behind door 42 under the influence of gravity.

[0022] As shown, second flange 57 is generally perpendicular to first flange 56. Second flange 57, however, may extend outwardly from first flange 56 at any angle that is suitable to direct water away from the internal cavity 22 and the opening 40. For example, second flange 57 may be angled downwardly relative to first flange 56 so that the water flows away from first flange 56 towards lip 58 under the influence of gravity. Furthermore, second flange 57 may be crowned at a medial location between the opposed ends of the first flange 56 so that the water flows in the direction of side walls 34 under the influence of gravity. As best shown in FIG. 4, the cross sectional shape of channeling means 54 (e.g., first flange 56, second flange 57, and lip 58) is generally U-shaped. The cross sectional shape of channeling means 54, however, may have any other convenient shape, such as C-shaped. Furthermore, channeling means 54 may comprise only first flange 56 and second flange 57 and may have any suitable cross sectional shape, such as L-shaped or V-shaped.

[0023] Most importantly, slide plate 50 is seamless. As used herein, “seamless” means that channeling means 54 extends continuously at least the entire width of the opening 40. Thus, there are no discontinuities, and in particular no vertical seams 17 (FIG. 1), along channeling means 54 to permit water that collects on second flange 57 to seep into the interior cavity 22 of the enclosure 20. As shown in FIG. 5, door 42 of housing 30 overlies the lower portion of first flange 56, second flange 57, and lip 58. Accordingly, once rain cap 60 is removed and a subsequent enclosure is vertically stacked on top of enclosure 20, any water that collects on second flange 57 could seep into the internal cavity 22 of the enclosure 20 if channeling means 54 did not extend continuously at least the entire width of the opening 40. Preferably, housing 30 of outdoor enclosure 20 further comprises vertical rain channels 48 (FIG. 2) affixed to flanges 33 of side walls 34 and extending outwardly therefrom adjacent opening 40. Rain channels 48 are positioned inwardly of door 42 so that the door 42 closes over the rain channels 48 along with the lower portion of first flange 56, second flange 57, and lip 58. Channeling means 54, and in particular second flange 57, extend at least to, and preferably slightly beyond the vertical rain channels 48. As a result, water on second flange 57 is directed laterally and then downwardly along rain channels 48 under the influence of gravity past opening 40.

[0024] In operation, a craftsperson installs the enclosure 20 in the distribution network by securing housing 30 to a structural element, such as the exterior wall of a building, using fasteners that pass through the holes 31 provided on back wall 32. The enclosure is installed with the side walls 34 oriented vertically and the floor 36 and top wall 38 oriented horizontally. The distribution network service cable 21 is then routed through the hole 37 into the interior cavity 22 defined by the enclosure 20. Typically, the insulation of the service cable 21 is then partially removed to permit any required wiring connections 23 to be made in the interior cavity 22. For example, the craftsperson may route a 100 pair telephone service cable 21 into the enclosure 20 and drop-off only 50 pair for making wiring connections 23 to existing subscriber drop lines 27 (FIG. 2) of subscriber drop line cable 25 routed through the second hole 37 provided in floor 36. Once the desired wiring connections 23 are made, the unused, or “dark,” portion of service cable 21 is coiled and stored within the housing 30. If not already assembled, slide plate 50 is removably attached to housing 30 by fasteners that pass through holes 55 formed in first flange 56 of slide plate 50 and are received in holes 35 provided in flanges 33 of side walls 34. Rain cap 60 is then removably attached to housing 30 by passing downwardly extending posts 65 through holes 51 formed in top portion 52 of slide plate 50 and are received in holes 61 provided in flanges 62 of side walls 34. Finally, door 42 (if provided) is moved to the closed position covering opening 40 and secured to latch 46 in a conventional manner, for example by a lock (not shown).

[0025] Later, the service provider may desire to route the remaining 50 pair of the 100 pair telephone service cable 21 into a subsequent enclosure (not shown) for connection to additional subscriber drop lines. If so, the rain cap 60 and the slide plate 50 are removed from housing 30 and the door 42 (if provided) is moved to the opened position exposing opening 40 and interior cavity 22 of enclosure 20. The subsequent enclosure is then positioned on top of enclosure 20, vertically aligned and secured to the structural element in a conventional manner. The unused portion of telephone service cable 21 is next uncoiled and routed through hole 39 defined by the inner edge 53 of top portion 52 of slide plate 50 and top wall 38. The additional subscriber drop lines of subscriber drop line cable 25 are then routed into the subsequent enclosure through the second hole 39 defined by inner edge 53 of slide plate 50 and top wall 38. The desired additional wiring connections are made in the interior cavity of the subsequent enclosure and any still unused portion of service cable 21 is coiled and stored within the housing of the subsequent enclosure for further future expansion in yet another subsequent enclosure that is stacked vertically on top the first subsequent enclosure.

[0026] Obviously, those skilled in the art will immediately appreciate that many alternative embodiments of the invention described herein are possible without departing from the spirit of the invention. Accordingly, it is intended that the invention be construed broadly enough to encompass any and all alternative embodiments that are within the spirit and scope of the invention as illustrated and described by the written description, accompanying drawings and appended claims.

Claims

1. An enclosure comprising a housing defining an internal cavity and having an opening for providing access to the internal cavity; and

a slide plate removably attached to the housing, the slide plate extending at least the entire width of the opening of the housing.

2. The enclosure of claim 1 wherein the housing comprises a back wall, a pair of side walls affixed to and depending outwardly from the back wall, a floor affixed to and depending outwardly from the back wall, the floor affixed to and extending between the side walls, a top wall affixed to and depending outwardly from the back wall, the top wall affixed to and extending between the side walls opposite the floor.

3. The enclosure of claim 2 further comprising a door attached to the housing and movable between a closed position covering the internal cavity defined by the housing and an opened position exposing the internal cavity defined by the housing.

4. The enclosure of claim 3 wherein the door is hinged to the housing adjacent one of the side walls.

5. The enclosure of claim 1 further comprising a rain cap affixed to the housing and overlying the slide plate.

6. The enclosure of claim 3 wherein an inner edge of the slide plate is positioned adjacent the top wall of the housing and the slide plate comprises channeling means for preventing water from entering the internal cavity defined by the housing, the channeling means extending continuously between the side walls of the housing at least the entire width of the opening of the housing.

7. The enclosure of claim 3 wherein an inner edge of the slide plate is positioned adjacent the top wall of the housing and the slide plate comprises a downwardly depending first flange and an outwardly depending second flange for preventing water from entering the internal cavity defined by the housing, the second flange extending continuously between the side walls of the housing at least the entire width of the opening of the housing.

8. The enclosure of claim 2 wherein the slide plate defines at least one passageway with the top wall of the housing for permitting the passage of an electrical cable therethrough.

9. The enclosure of claim 2 wherein the top wall of the housing depends outwardly from the back wall of the housing along a portion of the side walls and the slide plate extends inwardly in the direction of the back wall of the housing along the remaining portion of the side walls and wherein the slide plate defines at least one passageway with the top wall of the housing for permitting the passage of an electrical cable therethrough.

10. The enclosure of claim 9 wherein the slide plate comprises a first horizontal flange adjacent the top wall of the housing, a second flange depending vertically downwardly from the first flange, and a third flange depending outwardly from the second flange, the second and third flanges extending continuously at least the entire width of the opening defined by the housing.

11. The enclosure of claim 10 further comprising a lip depending upwardly from the third flange and wherein the second flange, the third flange and the lip define a generally J-shaped cross section.

12. An outdoor enclosure defining an internal cavity for receiving an electrical cable and for protecting electrical wiring connections within the cavity from exposure to adverse environmental conditions, the enclosure comprising

a housing having a back wall, a pair of side walls affixed to and depending outwardly from the back wall, a floor affixed to and depending outwardly from the back wall, the floor affixed to and extending between the side walls, a top wall affixed to and depending outwardly from the back wall, the top wall affixed to and extending between the side walls opposite the floor, the top wall, the floor, and the side walls of the housing defining an opening; and

a slide plate removably attached to the housing, the slide plate extending continuously between the side walls of the housing at least the entire width of the opening of the housing.

13. The outdoor enclosure of claim 12 further comprising a door attached to the housing adjacent a side wall of the housing, the door being movable between a closed position covering the opening of the housing and an opened position exposing the internal cavity defined by the enclosure.

14. The outdoor enclosure of claim 13 wherein an inner edge of the slide plate is positioned adjacent the top wall of the housing and wherein the slide plate comprises channeling means for preventing the adverse environmental conditions from entering the internal cavity defined by the enclosure, the channeling means extending continuously between the side walls of the housing at least the entire width of the opening of the housing.

15. The outdoor enclosure of claim 13 wherein an inner edge of the slide plate is positioned adjacent the top wall of the housing and wherein the slide plate comprises a downwardly depending first flange and an outwardly depending second flange for preventing the adverse environmental conditions from entering the internal cavity defined by the enclosure, the second flange extending continuously between the side walls of the housing at least the entire width of the opening of the housing.

16. The outdoor enclosure of claim 12 wherein the slide plate defines at least one passageway with the top wall of the housing for permitting the passage of an electrical cable therethrough.

17. The outdoor enclosure of claim 12 wherein the top wall of the housing depends outwardly from the back wall of the housing along a portion of the side walls and the slide plate extends inwardly in the direction of the back wall of the housing along the remaining portion of the side walls and wherein the slide plate defines at least one passageway with the top wall of the housing for permitting the passage of an electrical cable therethrough.

18. An outdoor enclosure for use in a communications service network, the enclosure defining an internal cavity for receiving an electrical cable and for protecting wiring connections within the cavity from exposure to adverse environmental conditions, the enclosure comprising:

a housing having a rear wall, a pair of opposed side walls affixed to and depending outwardly from the rear wall, a floor affixed to and depending outwardly from the rear wall and affixed to and extending between the side walls, a top wall affixed to and depending outwardly from the rear wall and affixed to and extending between the side walls opposite the floor, and a door hingedly attached to the housing opposite the rear wall and extending between the side walls; and

a slide plate having an inner edge positioned adjacent the top wall of the housing and extending between the opposed side walls, the slide plate defining at least one opening with the top wall for permitting the passage of the electrical cable therethrough, the slide plate comprising a continuous channel extending at least the entire width of the door to prevent the entry of the adverse environmental conditions into the internal cavity defined by the enclosure.