GB2375661A

GB2375661A - Electrical cable junction box

Info

Publication number: GB2375661A
Application number: GB0210534A
Authority: GB
Inventors: Kimleigh George Montag Pratley; Keith Alan Jones
Original assignee: Pratley Investments Pty Ltd
Current assignee: Pratley Investments Pty Ltd
Priority date: 2001-05-08
Filing date: 2002-05-08
Publication date: 2002-11-20
Anticipated expiration: 2022-05-08
Also published as: GB2375661B; AU3822802A; AU783167B2; GB0210534D0

Abstract

The invention provides for an electrical cable junction box having a box section [10] and a lid [50]. The box section [10] includes a base [16] and at least one side wall [14] defining a plurality of apertures [12] each adapted to receive a cable gland for a cable, or a conduit. The electrical cable junction box also includes a rail insert [70] which has a rail [72] for holding one or more rail mounted connectors [104, 106] and a mounting formation [76] at or near each end of the rail. The rail [72] has a width which is sized to receive a first sized rail mounted connector [104] and an elongate slot which is sized to receive a second sized rail mounted connector [106]. A pair of bosses [32] are provided in the box section [10] for engaging the mounting formations [76] on the rail insert [70] and mounting the rail insert [70] in the box section [10].

Description

ELECTRICAL CABLE JUNCTION BOX BACKGROUND OF THE INVENTION THIS invention relates to an electrical cable junction box.

Electrical cable junction boxes, also termed electrical connection boxes, generally consist of a hollow box section and a removable lid. Typically, the box section includes one or more apertures which are designed to receive cable glands or electrical conduits. In practice, the conductors of electrical cables pass through the side walls of the box section into the hollow interior of the box section where they are interconnected using electrical connection blocks or terminals.

It is an object of the present invention to provide an electrical cable junction box which includes an alternative mechanism for interconnecting conductors of cables in a box section thereof, and for ensuring earth continuity for armoured cables.

SUMMARY OF THE INVENTION According to the invention there is provided an electrical cable junction box comprising : a box section having a base and at least one side wall, the at least one side wall including one or more apertures each adapted to receive a cable gland for a cable, or a conduit; a lid for the box section ; a rail insert including ; a rail for holding one or more rail mounted connectors, the rail having a width which is sized to receive a first sized rail mounted connector and an elongate slot which is sized to receive a second sized rail mounted connector, and a mounting formation at or near each end of the rail ; and rail insert mounting means in the box section which is engageable with the mounting formations on the rail insert for mounting the rail insert in the box section.

In a preferred embodiment of the invention, each mounting formation on the rail insert comprises a leg which terminates in a foot defining an aperture, and the legs of the mounting formations serve to raise the rail off the base of the box section, in use.

In one arrangement, the rail insert mounting means in the box section comprises a pair of bosses on the base of the box section, the bosses

including apertures which are alignable with the apertures in the mounting formations on the rail insert so that a fastening element can be located In the aligned apertures to mount the rail insert in the box section.

The rail insert may be shaped and dimensioned so that it is locatable in the box section in an inverted position when not required with the feet of the mounting formations mounted to the bosses on the base of the box section.

Typically, the rail insert is formed from an electrically conductive material.

Preferably, the electrical cable junction box includes two electrically conductive earth harness inserts which are adapted to be mounted in the box section.

Each earth harness insert may include an aperture which is alignable with an aperture in the at least one side wall of the box section, and a section for connection to the rail insert to provide earth continuity.

The box section preferably includes earth harness insert mounting means for mounting the earth harness inserts in the box section.

In one arrangement, the section of each earth harness insert for connection to the rail insert comprises a lug defining an aperture. In this case, the lug may be adapted to be placed over or under one of the feet of the rail insert so that the aperture in the lug is aligned with the aperture in the foot and a fastening element can be located in the apertures to connect the rail insert to the earth harness insert when the rail inserted is mounted in the box section.

The box section may include additional mounting means for mounting each earth harness insert in the box section with the apertures in the earth harness inserts in register with the apertures in the at least one side wall of the box section.

The additional mounting means may be shaped to receive a nut adapted to cooperate with a cable gland located in an aperture In the at least one side wall of the box section.

Each earth harness insert may include a protrusion adapted to protrude through the box section to provide an outside earth connection point.

The invention extends to a box section for use in an electrical cable junction box as described above.

The invention also extends to a rail insert for use in an electrical cable junction box as described above.

The invention still further extends to an earth harness insert for use in an electrical cable junction box as described above.

The invention also provides for a rail insert for rail mounted connectors, the rail insert including: a rail for holding one or more rail mounted connectors, the rail having a width which is sized to receive a first sized rail mounted connector and an elongate slot which is sized to receive a second sized rail mounted connector, and a mounting formation at or near each end of the rail.

In one arrangement, each mounting formation includes a leg for raising the rail off a base of a box section of an electrical cable junction box.

The mounting formations may be adapted for mounting to a pair of bosses on a base of a box section of an electrical cable junction box.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a plan view of a box section of an electrical cable junction box according to the present invention; Figure 2 shows a cross-sectional view along the line X-X in Figure 1; Figure 3 shows a side view of the box section of Figure 1; Figure 4 shows a cross-sectional view along the line Y-Y in Figure 1; Figure 5 shows an underplan view of the box section of Figure 1; Figure 6 shows a plan view of a lid for the box section of Figure 1; Figure 7 shows a cross-sectional view along the line Z-Z in Figure 6; Figure 8 shows a plan view of a rail insert for use with the box section of Figure 1; Figure 9 shows a side view of the rail insert of Figure 8 ; Figure 10 shows an end view of the rail insert of FIgure 8; Figure 11 shows a side view of an earth harness insert for use with the box section of Figure 1 ;

Figure 12 shows a plan view of the earth harness insert of Figure 11; Figure 13 shows a perspective view of the box section of Figure 1 with the rail insert of Figure 8 mounted therein in an inverted position; Figure 14 shows a perspective view of the box section of Figure 1 with the rail insert of Figure 8 mounted therein in an operative position; Figure 15 shows a cross-sectional view of a box section of an electrical cable junction box according to another embodiment of the invention; and Figure 16 shows a plan view of a rail insert for use with the box section of Figure 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Figures 1 to 5 of the accompanying drawings illustrate a box section 10 of an electrical cable junction box according to the present invention. The box section 10 includes five apertures 12, four in the side wall 14 of the box section and one in the base 16 of the box section. Each aperture 12 is designed to receive a cable gland or an electrical conduit. The apertures 12 may be sealed prior to use by means of a suitably thick web of plastics material which can be drilled or broken out, as required. It will be appreciated that the box section 10 could have other suitable configurations of apertures 12 for receiving cable glands or electrical conduits.

Eight equally spaced protrusions 18 are located around the outer periphery of the box section 10. With particular reference to Figure 3 of the drawings, each

protrusion 18 is seen to include a sloping surface 20 on a lower edge thereof, and a stop 22 is located at an end of one of the protrusions 18 to prevent overtightening of a lid onto the box section 10.

The box section 10 also includes a secural point formed by a lug 24 which defies an aperture 26. The method of securing a lid to the box section utilising the securat point will be described in more detail below.

With reference to Figure 2, a gasket or sealing ring 28 may be located in a groove 30 in the box section 10 so that when a lid is placed onto the box section 10, the sealing nng or gasket 28 is compressed between the lid and the box section to ensure a seal between the lid and the box section.

Located on the base 16 of the box section 10 are two bosses 32, each of which includes an aperture 34. The bosses 32 are designed for mounting a rail insert as will be described in more detail below.

The box section 10 also includes formations 36, each associated with an aperture 12 in the side wall 14 of the box section, for receiving an earth harness insert and a nut for a cable gland as will be described In more detail below.

In Figures 4 and 5 of the drawings, the base 16 of the box section 10 is seen to include four feet 38 which stand proud of the base 16 so as to accommodate unevenness in a surface to which the box section 10 is mounted. Each foot 38 includes an aperture 40 for attaching the box section 10 to a surface- In the illustrated embodiment, the box section 10 is moulded in one piece from a thermoplastic material. However, the box section 10 could also be moulded in two or more pieces so that different types of materials can be used for the separate pieces The pieces may then be clipped together, screwed together

or glued together to form the box section 10. The box section 10 may also be manufactured by means other than moulding and from other materials such as, for example, a suitable metallic material.

Referring now to Figures 6 and 7, a lid 50 for the box section 10 Includes eight protrusions 52 on the inner penphery of the lid. The protrusions 52 are complementary to the protrusions 18 on the box section 10 and accordingly include sloping surfaces 54 on upper edges thereof.

In practice, the lid 50 is located on the box section 10 with the protrusions 52 on the lid located between the protrusions 18 on the box section, and the lid 50 is then rotated on the box section 10 to bring the sloping surfaces 20 and 54 into engagement with one another, thereby to releasably engage the lid 50 on the box section 10 in a closed condition. As indicated above, the stop 22 prevents over-tightening of the lid 50 on the box section 10.

The lid 50 also includes two lugs 56 for facilitating the removal of the lid from the box section 10 with a bar (not illustrated). In this regard, the lugs 56 are designed so that the bar may be placed on the lid between the two lugs and rotated to lever the lid 50 off the box section 10.

The lid 50 is seen in Figure 6 to carry a secural point in the form of a lug 58 defining an aperture 60. When the lid 50 is rotated into the closed condition on the box section 10, the lugs 24 and 58, and thus the apertures 26 and 60, are aligned with one another. The lid 50 may then be secured to the box section 10 by means of any suitable securing device which can only be unsecured using a tool, such as, for example, a bolt secured in the apertures by means of a nut, a cable tie, or a padlock.

As with the box section 10, the lid 50 may be moulded in one piece from a thermoplastics material. Alternatively, the lid 50 may be moulded in two or

more pieces so that different types of materials can be used for the separate pieces. The pieces may then be clipped together, screwed together or glued together. The lid may also be manufactured by means other than moulding and from other materials such as a suitable metallic material.

If desired, the box section 10 and/or the lid 50 may be formed from a clear plastics material so as to allow visual inspection of the interior of the box section.

Figures 8 to 10 of the accompanying drawings illustrate a rail insert 70 for the box section 10. The rail insert 70 includes a rail 72 which defines a slot 74 therein, and mounting formations at the ends of the rail 72 in the form of two legs 76 each of which terminates in a foot 78 defining an aperture 80.

Typically, the rail insert 70 is formed from an electrically conductive material such as, for example, brass.

In Figures 11 and 12 there is shown an earth harness insert 90 which includes two arms 92 each of which includes an aperture 94 which is associated with one of the apertures 12 in the side wall 14 of the box section 10- The earth harness insert 90 also includes a central section 96 which carries a lug 98 with an aperture 100. As can be seen, the arms 92 are shaped to fit into the formations 36 in the box section 10. The earth harness insert 90 is also formed from an electrically conductive material such as, for example, brass. Each earth harness insert 90 may in addition have a protrusion (not illustrated) adapted to protrude through the box section 10 to provide an outside earth connection point.

The use of the rail insert 70 and earth harness inserts 90 in the box section 10 will now be described with reference to Figures 13 and 14 of the accompanying drawings.

With reference first to Figure 14 (which illustrates the rail insert 70 mounted in an operative position In the box section 10 together with two earth harness inserts 90), when it is desired to install the rail Insert 70 and the earth harness inserts 90 in the box section 10, the two earth harness inserts 90 are slipped into the formations 36 in the box section so that the apertures 94 in the earth harness inserts 90 are aligned with the apertures 12 in the side wall 14 of the box section In this position, the lug 98 of each earth harness insert 90 rests on one or other of the bosses 32 in the box section 10 with the apertures 100 and 34 aligned with one another.

The rail insert 70 is then placed in the box section 10 with the feet 78 on top of the lugs 98 of the earth harness inserts 90 so that the apertures 80,100 and 34 are all aligned with one another. Thereafter, a fastening element 102 is threaded through the apertures 80,100 and 34 to secure the rail insert 70 and the earth harness inserts 90 in the box section 10.

Cable glands (not illustrated) may be fitted into the apertures 12 in the side wall 14 of the box section 10. The nuts associated with such cable glands fit neatly into the formations 36 in the box section 10 and hold the earth harness inserts 90 in position against rotation. Furthermore, the connection of the cable glands with the earth harness inserts 90 and thus with the rail insert 70 ensure earth continuity.

In practice, rail mounted connectors of two different sizes, a standard rail mounted connector 104 (illustrated in broken outline) and a miniature rail mounted connector 106 (also illustrated in broken outline), may be mounted on the rail 72 or in the slot 74 of the rail insert 70, as shown. It will be appreciated that this feature of the rail insert 70 is advantageous in that it allows for two different sizes of rail mounted connectors to be accommodated within the box section 10 on a single rail insert.

As the rail 72 of the rail insert 70 is raised above the base 16 of the box section 10, wires from the cables entering the box section can be routed underneath the rail 72 for ease of fitting, In addition, as the rail mounted connectors 104 and 106 are raised above the base 16 of the box section 10, termination of the wires from the cables is carried out level with the top of the box section 10, making this a simpler procedure. Also, the elevated position of the rail 72 relative to the base 16 of the box section 10 allows an electrician or an inspector to physically see inside the entrances of the rail mounted connectors to verify that the wires have been properly terminated.

Where it is not necessary to use the rail insert 70 in the box section 10, it can be inverted and stored in the box section in the manner illustrated in Figure 13In this condition, the apertures 12 in the side wall 14 of the box section 10 can still accommodate cable glands. Also, since the slot 74 in the rail insert 70 extends across the aperture 12 in the base of the box section 10. cables may pass into the box section through this aperture 12. In the Figure 13, inverted condition, the rail insert 70 can still act to provide earth continuity.

An electrical cable junction box consisting of the box section 10, the lid 50. the rail insert 70 and the earth harness inserts 90 may be sold for use either for the interconnection of armoured cables, in which case the rail insert 70 and the earth harness inserts 90 will be utilised as illustrated in Figure 14, or for the interconnection of unarmoured cables, in which case the earth harness inserts 90 may not be used and the rail insert 70 is placed in the box section 10 as illustrated in Figure 13.

Another embodiment of the rail insert according to the present invention is illustrated in Figures 15 and 16 of the accompanying drawings. Figure 15 illustrates a box section 120 of an electrical cable junction box which is similar to the box section 10 of Figures 1 to 5, except for the following. Located on the base 122 of the box section 120 are two bosses 124 each including an

aperture 126. These bosses 122 are substantially taller than the bosses 34 of the box section 10 of Figures 1 to 5.

Figure 16 illustrates a rail insert 128 for use with the box section 120. The rail insert 128 includes a rail 130 with a slot 132 therein, and two mounting formations in the form of end pieces 134, each of which defines an aperture 136. The rail insert 128 is attached to the bosses 124 by means of screws 138, as shown In Figure 15.

In use, rail mounted connectors of two different sizes, a standard rail mounted connector and a miniature rail mounted connector, may be mounted on the rail 130 or in the slot 132 of the rail insert 128, respectively, in a similar manner to that described above with reference to Figure 14 of the drawings.

The raising of the rail 130 of the rail insert 128 above the base 122 of the box section 120 results in the same advantages described above with reference to the rail insert 70, i. e. wires from cables entering the box section 120 can be routed undemeath the rail 130 for ease of fitting, termination of the wires from the cables is carried out level with the top of the box section 120, making this a simpler procedure, and an electrician or an inspector can physically see inside the entrances of the rail mounted connectors to verify that the wires have been properly terminated.

Claims

CLAIMS 1. An electrical cable junction box comprising : a box section having a base and at least one side wall, the at least one side wall including one or more apertures each adapted to receive a cable gland for a cable, or a conduit; a lid for the box section; a rail insert including : a rail for holding one or more rail mounted connectors, the rail having a width which is sized to receive a first sized rail mounted connector and an elongate slot which is sized to receive a second sized rail mounted connector, and a mounting formation at or near each end of the rail ; and rail insert mounting means in the box section which is engageable with the mounting formations on the rail insert for mounting the rail insert in the box section.
2. An electrical cable junction box according to claim 1, wherein each mounting formation on the rail insert comprises a leg which terminates in a foot defining an aperture, and wherein the legs of the mounting formations serve to raise the rail off the base of the box section, in use.
3. An electrical cable junction box according to claim 2, wherein the rail insert mounting means in the box section comprises a pair of bosses on

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the base of the box section, the bosses including apertures which are alignable with the apertures in the mounting formations on the rail insert so that a fastening element can be located in the aligned apertures to mount the rail insert in the box section.
4. An electrical cable junction box according to claim 3, wherein the rail insert is shaped and dimensioned so that it may be located in the box section in an inverted position when not required with the feet of the mounting formations mounted to the bosses on the base of the box section.
5. An electrical cable junction box according to any one of the preceding claims, wherein the rail insert is formed from an electrically conductive material.
6. An electrical cable junction box according to any one of the preceding claims, including two electrically conductive earth harness inserts adapted to be mounted in the box section, each earth harness insert including an aperture which is alignable with an aperture in the at least one side wall of the box section, and a section which is connectable to the rail insert to provide earth continuity.
7. An electrical cable junction box according to claim 6, wherein the box section includes earth harness insert mounting means for mounting the earth harness inserts in the box section.
8. An electrical cable junction box according to either claim 6 or claim 7, wherein the section of each earth harness insert for connection to the rail insert comprises a lug defining an aperture, and wherein the lug is adapted to be placed over or under one of the feet of the rail insert so that the aperture in the lug is aligned with the aperture in the foot and a

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fastening element can be located in the apertures to connect the rail insert to the earth harness Insert when the rail inserted is mounted in the box section.
9. An electrical cable junction box according to claim 8, wherein the box section includes additional mounting means for mounting each earth harness insert in the box section.
10. An electrical cable junction box according to claim 9, wherein the additional mounting means is shaped to receive a nut adapted to co- operate with a cable gland located in an aperture in the at least one side wall of the box section.
11. An electrical cable junction box according to any one of claims 6 to 10, wherein each earth harness insert includes a protrusion adapted to protrude through the box section to provide an outside earth connection point.
12. A box section for an electrical cable junction box according to any one of the preceding claims.
13. A rail insert for an electrical cable junction box according to any one of the preceding claims.
14. An earth harness insert for an electrical cable junction box according to any one of the preceding claims.
15. A rail insert for rail mounted connectors, the rail insert including: a rail for holding one or more rail mounted connectors, the rail having a width which is sized to receive a first sized rail

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mounted connector and an elongate slot which is sized to receive a second sized rail mounted connector, and a mounting formation at or near each end of the rail.
16 A rail insert according to claim 15, wherein each mounting formation includes a leg for raising the rail off a base of a box section of an electrical cable junction box.
17. A rail insert according to either claim 15 or claim 16, wherein the mounting formations are adapted for mounting to a pair of bosses on a base of a box section of an electrical cable junction box.
18. An electrical cable junction box substantially as described herein with reference to the accompanying drawings.
19. A rail insert substantially as described herein with reference to the accompanying drawings.