GB2129230A - Splice enclosure for buried cable - Google Patents

Abstract

A cable splice is enclosed by a) wrapping a collar (27, 28) about the cables (21-24) on each side of the splice zone; b) enclosing the splice in blocks of grease (32); c) wrapping the splice in plastic sheet(s) (34) which extend over each cable; d) taping the sheets in place over each collar; e) squeezing to force the grease into the interstices of the splice; f) enclosing the wrapped splice in a foam sheet (42); and g) taping the foam enclosure with a stretchable tape (48) under tension. <IMAGE>

Description

SPECIFICATION Splice enclosure for buried cable and the like and method of making same This invention relates to electrical cable splices and in particular to a new and improved splice enclosure suitable for burying in the ground.

Varius types of splice enclosures have been used and are being used. A major problem with buried splices is keeping moisture out of the splice, and this problem usually is overcome by one of two approaches. In one type of enclosure, a hermetically sealed case is utilized, with the interior of the case charged with a dry gas. In the other type of enclosure, the splice is positioned within some type of housing or casing and the interior of the casing is filled with a sealing compound. The hermetically sealed type of enclosures are relatively expensive and subject to leakage problems. The sealing compounds used in the second type usually have to be prepared on the site for pouring into the casing.Preparation and completion of these types of enclosures are time consuming, and it is very difficult to make changes since the entire splice area becomes permeated with the solidified sealing compound.

It is an object of the present invention to provide a new and improved splice enclosure and method of making same which is relatively quick and easy to carry out and which is relatively inexpensive. A particular object is to provide such a splice enclosure which does not require hermetic sealing or charging with gas, not one which requires preparation and pouring of a sealing compound and setting up of the compound.

It is a further object of the invention to provide such a splice enclosure and method of making same which is easily performed by the worker in the field, and which requires no special mixing or preparation of components.

These and other objects, advantages, features and results will more fully appear in the course of the following description.

A method of enclosing an electrical cable splice having a plurality of cable conductors joined together in an splice zone, and an electrical cable splice enclosure. The method includes wrapping a collar about the cables on each side of the splice zone, applying first and second blocks of grease on opposite sides of the splice between the collars to form a grease enclosed splice, wrapping the grease enclosed splice in a plastic sheet with the sheet extending over each of the collars, taping the plastic sheet in place at each of the collars and squeezing the wrapped splice to force the grease into the interstices of the splice, enclosing this wrapped splice in a foam sheet, and taping the foam enclosure with a stretchable tape under tension.Preferably the stretchable tape is wrapped over the foam enclosure starting at the center of the splice and taping to one end, and again starting at the center of the splice and taping to the opposite end.

The invention also includes the new splice enclosure as produced by the method described herein.

In the drawings, Figs. 1-8 are isometric views illustrating steps in the production of an electrical cable splice enclosure incorporating one embodiment of the invention, where Fig. 1 shows the cable splice with collars on each side of the splice zone, Fig. 2 shows one of the blocks of the grease and its wrapping sheet, Fig. 3 shows the positioning of the two blocks of grease, Fig. 4 shows the wrapped splice with plastic sheet and taped ends, Fig. 5 shows the positioning of the foam sheet, Fig. 6 shows the trimming of the folded foam sheet, Fig. 7 shows the first taping with stretchable tape, and Fig. 8 shows the completed splice enclosure; and Figs. 9 and 10 illustrate an alternative and presently preferred embodiment, with the steps in Figs. 9 and 10 corresponding to the steps in Figs.

5 and 7, respectively.

In Fig. 1 , the electrical conductors of cables 21, 22, 23 and 24 are joined together as desired to form a cable splice, with the cables being held in position by a frame member 26. Collars 27, 28 are provided on the cables on each side of the splices, defining a splice zone, therebetween. The collars 27, 28 may be formed by wrapping with conventional sealing mastic type of tape.

Next two blocks of grease 31, 32 are placed on opposite sides of the splice between the collars and are wrapped in placed by plastic sheets 33, 34. The grease serves as a sealant and may be a conventional product, typically a silicone grease having good electrical insulating properties and not miscible with water. This material should be of a gel or grease-like consistency and one which does moh set up but rather stays flowable during the normal life expentancy of the splice. Typically each block of grease is in the order of one-half by two by eight inches.

Preferably, each block of grease is supplied to the worker already wrapped in the plastic sheet.

Then the worker opens the sheet to the configuration shown in Fig. 2, places the splice on the lower block 32, and the places the upper block 31 on the splice.

Afer wrapping, the ends of the plastic sheet or sheets are tightly taped in place at each of the collars to form a wrapped splice, as shown in Fig.

4. The taping at 37, 38 may be carried out by using a conventional plastic tape. This taping provides a seal for the grease and prevents grease leakage during subsequent steps of the process.

After taping, the worker manually squeezes the wrapped splice 39 to force the grease into the interstices of the splice.

Next, the wrapped splice 39 is enclosed in a foam sheet to produce a foam enclosure. In the embodiment illustrated in Figs. 5-7, a sheet 42 of foam, typically sponge neoprene, having a self adhesive layer 43 protected by a peelable sheet 44 is utilized. The sheet 42 typically one-quarter inch thick, of a length to overlie the wrapped splice 39, and of a width to permit folding the sheet on itself and joining of the opposite edges, as shown in Fig. 6. In use, the backing sheet 44 is peeled off, the wrapped splice 39 is laid in place on the self-adhesive face 43, and the foam sheet is folded over the wrapped splice bringing the edges 45, 46 together. The foam sheet may be manually squeezed onto the wrapped splice to improve the adhesion. Excess portions of the folded sheet may be trimmed away as shown in Fig. 6.

Next, the foam enclosure is wrapped with a stretchable tape applied under tension, typically a neoprene stretch tape two inches wide. As shown in Fig. 7, the wrapping with the stretchable tape 48 is started at the center of the splice and progresses toward one end, preferably with a half-width overlap. Next the stretchable tape wrapping is again started at the center and carried out to the other end. This wrapping operation with the stretchable tape under tension provides a compression force along the entire length of the splice enclosure serving to force the grease intimately into contact with the cable and conductors and to force the grease to each end of the splice enclosure.

The foam enclosure provides a smooth and firm base or taping, and provides mechanical protection to the splice.

As a final step, the ends of the stretchable tape 48 may be wrapped with the conventional plastic tape as shown in Fig. 8, at the center 50 and at each end 51, 52, thereby completing the electrical cable splice enclosure. The splice enclosure has been completed without requiring any special tools and without requiring any special manipulation techniques. The splice enclosure is ready to bury immediately upon completion without requiring any set up time and without requiring any charging by a dry gas. The grease blocks intimately worked into the components provides the desired protection against intrusion of moisture. The foam enclosure with the stretchable tape wrapping provides high impact resistance to the splice enclosure The alternative embodiment illustrated in Figs.

9 and 1 0 utilizes a foam sheet 55 in place of the foam sheet 42. The sheet 55 typically is one-half the thickness of the sheet 42, but has at least twice the width, with the sheet 55 being wrapped about the wrapped splice 39, as shown in Fig. 1 0, rather than being folded as shown in Figs. 6 and 7. This embodiment does not require trimming, and eliminates the problem of the folded foam sheet separating during subsequent wrapping.

In the embodiment of Figs. 9 and 10, after wrapping by the foam sheet, the stretchable tape wrapping is performed in the same manner as described in conjunction with Figs. 7 and 8.

Claims (13)

Claims

1. A method of enclosing an electrical cable splice having a plurality of conductors joined together in a splice zone, including the steps of: wrapping a collar about the cables on each side of the splice zone; applying first and second blocks of grease on opposite faces of the splice between the collars and with the splice therebetween to form a grease enclosed splice; wrapping the grease enclosed splice in a plastic sheet, with the sheet extending over each of the collars; taping the plastic sheet in place over each of the collars to form a wrapped splice; squeezing the wrapped splice to force the grease into interstices of the splice; enclosing the wrapped splice in a foam sheet to form a foam enclosure; and taping the foam enclosure with a stretchable tape under tension to form the splice enclosure.

2. The method as defined in claim 1 including: providing each of the blocks of grease wrapped in a plastic sheet; partially unwrapping each block prior to applying the block to the splice; and using the block wrappings as the plastic sheet for wrapping the grease enclosed splice.

3. The method as defined in claim 2 including taping the foam enclosure with the stretchable tape under tension by starting at the centre of the splice zone and taping to one end, and then starting again at the center of the splice zone and taping to the other end.

4. The method as defined in claim 3 including taping the free ends of the stretchable tape at the center and each end of the splice enclosure.

5. The method as defined in claim 1 wherein the foam enclosure is produced by folding a foam sheet having a self-adhesive face, over the wrapped splice and joining the self-adhesive face to itself.

6. The method as defined in claim 1 wherein the foam enclosure is produced by wrapping a foam sheet having a self-adhesive face, over the wrapped splice with the self-adhesive face overlying the opposite face.

7. An electrical cable splice enclosure for a plurality of cable conductors joined together in a splice zone, including in combination: first and second collars wrapped about the cables on each side of said splice zone; first and second blocks of grease positioned on opposed faces of said splice between said collars and with said splice therebetween to form a grease enclosed splice; a plastic sheet wrapped about said grease enclosed splice and extending over each of said collars; tape wrapped over said plastic sheet at each of said collars to form a wrapped splice; a foam sheet overlying said wrapped splice to form a foam enclosure; and a stretchable tape under tension wrapped over said foam enclosure to form the splice enclosure.

8. A splice enclosure as defined in claim 7 with said foam sheet folded over said wrapped splice with the interface of said foam sheet joined to itself at the edges thereof.

9. a splice enclosure as defined in claim 7 or claim 8 with said foam sheet wrapped over itself over the wrapped splice.

10. A splice enclosure as defined in claim 7, claim 8 or claim 9 with said stretchable tape wrapped over said foam enclosure from the centre of said splice zone to each end thereof.

11. A splice enclosure as defined in claim 10 with a tape wrapping over the ends of said stretchable tape at the centre and ends of the splice enclosure.

12. Methods of making an enclosed splice substantially as herein described with reference to the accompanying drawings.

13. A splice enclosure substantially as herein described with reference to the accompanying drawings.