A cable assembly and method of manufacturing a cable assembly

Abstract

A cable assembly (100, 600, 700, 700') includes a structural component (622, 722, 722') that comprises an extruded plastic shell. The shell defines a plurality of cavities, including an external cavity (626, 726) and one or more further cavities (628, 728, 632, 732). A plurality of preterminated cable units (102) are housed within the first cavity. Different ones of the cable units extend over different portions (LI, L2,...Ln) of an overall length (Lo) of the cable assembly. In some embodiments, the shell further defines a fully enclosed internal cavity (632, 732) which may enclose a functional cable element (130). The functional cable element may for example be a microduct (734), which may be pre-populated with optical and / or electrical conductors (736, 738).

Description

[0001] A CABLE ASSEMBLY AND METHOD OF MANUFACTURING A CABLE ASSEMBLY

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates generally to cable assemblies and methods for use in the deployment of networks for communications and / or power supply. The invention may be used for example in the deployment of optical fibre broadband networks within neighbourhoods and large premises.

[0004] BACKGROUND TO THE INVENTION

[0005] Considering, for example, the deployment of optical fibre broadband connections to homes and business premises, it is known that fibre optic cables can be installed by a variety of methods, whether through the ground, via ducts, and via service spaces within buildings. Known methods include direct burying (trenching), pulling through ducts, pushing through ducts, blowing through ducts, aerial spans and combinations of these. Fibre-to-the- Premises (FTTP) is a generic term for broadband network architecture that uses optical fibre technology to carry data to a premises (whether residential or otherwise) from a broadband service provider via a telecommunications cabinet located near a customer premises. This is sometimes referred to as "last mile" connectivity.

[0006] In one type of deployment, individual premises are connected to a network via so-called drop terminals, that are positioned along a route and connected to a distribution point via one or more cables. Each drop terminal may supply one, two or many premises. By multiplexing several signals on a single optical fibre or pear optical fibres, several premises can be connected to the network using a splitter at the drop terminal. User terminals may also be connected wirelessly to a communications network, for example using Wi-Fi and / or 5G access points. These access points are connected to a distribution point of the network the optical fibre cables, and optionally power cables also.

[0007] In order to improve the quality and reduce the cost of building such networks, the use of preterminated cables is increasingly popular, as the complicated termination, splicing and other steps can be performed in a clean factory environment, rather than in the street. However, each deployment project is unique and to provide prefabricated cabling for each deployment remains complicated and expensive. SUMMARY OF THE INVENTION

[0008] In a first aspect of the present invention, there is provided a cable assembly comprising a series of cable units arranged within a supporting structure, each cable unit comprising a length of cable having a first end and a second end, wherein the supporting structure includes a structural component that forms a shell of the cable assembly, the shell at least partially enclosing a first cavity that extends within the structural component, wherein the first cavity houses at least a first subset of the series of cable units.

[0009] In some examples, the first cavity is formed with a longitudinally-extending opening such that the cable units can be inserted and / or removed without cutting the structural component.

[0010] The cable units housed in the first cavity may include one or more preterminated cable units, each preterminated cable unit having a first connector fitted at its first end and / or a second connector fitted at its second end.

[0011] A second aspect of the present invention provides a method of manufacturing a cable assembly, the method comprising the steps:

[0012] (a) providing a series of cable units, each cable unit comprising a length of cable having a first end and a second end;

[0013] (b) providing a structural component that comprises an extruded plastic shell structure in which a plurality of cavities are defined by cavity walls and connecting portions in a continuous profile, the cavities including a partially enclosed first external cavity and at least one fully enclosed internal cavity wherein at least one functional cable element is enclosed within the at least one internal cavity before the performance of step (c); and

[0014] (c) arranging the series of cable units within a supporting structure in such a way that successive cable units extend over different portions of an overall length of the cable assembly.

[0015] The cable units provided in step [a] may include one or more preterminated cable units, each preterminated cable unit having a first connector fitted at its first end and / or a second connector fitted at its second end. These and other features and advantages of the present disclosure will become apparent from a consideration of the claims and the following description and drawings.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Embodiments of the present disclosure will now be described by way of example only, with reference to the accompanying drawings, in which:

[0018] Figure 1 shows schematically a representative preterminated cable unit and a cable assembly incorporating a series of preterminated cable units arranged within a supporting structure;

[0019] Figure 2 to 4 illustrate schematically the cross-section of various example cable assemblies of the type illustrated in Figure 1, these examples including a structural component that forms a shell of the supporting structure in accordance with the first aspect of the present invention.

[0020] DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0021] Figure 1 illustrates schematically the form of a cable assembly 100 comprising a series of preterminated cable units 102, 102' etc. arranged within a supporting structure 120. A representative cable unit 102 is shown in enlarged detail at the top of the drawing. The cable unit comprises a length of cable, for example but not limited to an optical fibre cable. The preterminated cable units 102, 102' etc. are manufactured in advance such that each cable unit has a first connector 114 fitted at a first end and a second connector 116 fitted at a second end. Such preterminated cable units may be referred to in the art as "jumper cables". Once these jumper cables have been made to the required length and other specifications, they are assembled to form the cable assembly. Within the overall length Lo of the cable assembly, successive cable units extend over different portions or sub-lengths labelled LI, L2, ...Ln in the drawing.

[0022] In the following description, fibre optic cables are used as examples of cable units that may be included in the cable assembly, each cable unit containing one or more optical fibres. The structures and techniques disclosed herein are equally applicable for use with electrical (e.g. copper] cables and also for so-called 'hybrid' cables that carry both electrical and optical signals. The term 'cable' is understood to encompass any type of cable, unless the context requires otherwise. Of course, the types of connectors used and the types of cable used will the selected according to the particular types of signals that are to be carried through the connector.

[0023] For some use cases, it may be convenient that the lengths Ll-Ln of the portions are all identical. However, for a practical use case, the lengths of the cable units may all be individually customised in accordance with a planned route for installation of the cable, and the locations of certain terminals along that route. For the purposes of the present description, it may be assumed that all of the connectors 114, 116 are identical, but in principle they can be customised in different ways, to suit the application. The connectors may be of a "hardened" type, for use in an outdoor environment or they may be more conventional connectors. For optical connections, hardened connectors commercially available in the market include the long-established OptiTap® connectors and the more compact Pushlok™ type, available from Corning Optical Communications LLC, Charlotte, NC 28216, USA. Accessories are also available for converting between types of connectors, for example between the Pushlok type and the standard SC connectors. Another family of hardened connectors is the Prodigy® series from CommScope LLC in the USA (www.commscope.com / prodigy). Whichever type of connector is used, in the examples described herein it is assumed that the connectors are factory-fitted to pre-cut lengths of cable, prior to their inclusion in the overall cable assembly 100. In this way, operations to terminate optical fibres and / or electrical conductors in the individual cable units each are not required in the field, at the time of installation. Likewise, operations to terminate optical fibres and / or electrical conductors can be performed on the cable units individually, which is more convenient than performing operations to access and terminate cable units when they are already part of a larger cable assembly.

[0024] On the other hand, fitting of hardened connectors in the field is also possible and by no means excluded from the scope of the present disclosure. A cable unit that has only a cut end or a partial connector at one or both ends may be used instead of a cable unit preterminated with hardened connectors at both ends. Such a cable unit may be preferred for a given application, because it is more compact, for example. Accordingly, in the examples illustrated and described herein, it is an option to omit the hardened connector from one or both ends of one or more of the cable units. Concerningthe supporting structure 120 ofthe cable assembly 100, this is illustrated highly schematically in Figure 1, for the reason that it can be realised in a wide variety of ways. Some examples of possible supporting structures are illustrated and described below with reference to Figures 2 to 4. Whatever the construction, the aim is that the cable assembly can be manufactured, transported and installed along a desired route, while maintaining the arrangement of a series of preterminated cable units 102 within. After the assembly has been deployed along the route, the individual cable units can be broken out to serve their function as part of a distribution network for communication and / or power signals.

[0025] Still referring to Figure 1, in addition to the preterminated cable units 102, the cable assembly in some examples further includes at least one functional cable element 130 within the same supporting structure, separate from the series of preterminated cable units. As shown, the functional cable element 130 may extend in parallel with two or more of the preterminated cable units, optionally along the entire overall length of the cable assembly. More than one functional cable element may be provided in the same cable assembly. Many types of functional cable elements can be envisaged, and examples are described further below, with reference to Figures 2, 3 and 4. Functional cable elements may include optical conductors and / or electrical conductors. Functional cable elements may also include microducts. Such microducts may be pre-populated with optical conductors and / or electrical conductors. Such microducts may be left empty, to be used for installing additional optical and / or electrical conductors at a later date. In some examples, functional cable elements include at least one pre-populated microduct and at least one empty microduct.

[0026] For the avoidance of doubt, the terms "functional cable element" and "structural cable element" are used herein in the broadest possible sense. Structural cable elements of course have a function, but this function is related to the mechanical integrity of the cable assembly. Functional cable elements, as that term is used herein, are concerned with the function ofthe cable in carrying communications and / or power signals from place to place. The present disclosure is not concerned with cable assemblies that have a purely mechanical function. It will be further understood that the functions of functional cable element and structural cable element can be combined in various ways in a single component. For example, a composite cable may include optical and / or electrical conductors, while also providing a stiffness and / or tensile strength to the overall cable assembly.

[0027] EXAMPLE CABLE ASSEMBLIES WITH SHELL

[0028] There will now be described various examples of cable assemblies, in which the supporting structure 120 is provided by a continuous structural component that forms a shell of the cable assembly. This shell may be semi-rigid and have its own structural integrity. Conveniently, the structural component provides one or more cavities that are only partially enclosed and may be referred to as "external cavities”. The external cavity or cavities may have side openings through which cable units and connectors can be inserted or withdrawn after the structural component has been manufactured.

[0029] Plastic extrusion is a very convenient process by which continuous lengths of structural components can be manufactured, having complex cross-sections of the types described below.

[0030] In the illustrated examples, two external cavities are provided along opposite sides of the structural component. This allows two of the preterminated cable units to run in parallel along a given portion of the overall length, without sharing a cavity. More external cavities may be provided in other examples, or only one external cavity. Where multiple preterminated cable units extend in parallel over a given portion of the overall length, they may be arranged in respective individual cavities, or two or more preterminated cable units may share a cavity with one another.

[0031] Figure 2 shows a first example cable assembly 600, in a portion where two of the preterminated cable units 102 and 102' are overlapping. As a simple example, each cable unit 102, 102' in this example is shown containing a single optical fibre at its centre. It will be understood that cable units in practice may contain multiple optical fibres, for example 2 optical fibres, or up to 12, 24, 36 or more optical fibres. Where a cable unit has multiple optical fibres, the connectors terminating such cable units may provide connection to one or two or more of those optical fibres, as desired. In this example, the supporting structure includes a structural component 622 that extends continuously along the overall length of the cable assembly. The structural component comprises an extruded profile having outer portions 622a that form a shell of the cable assembly, and a connecting portion 622b. Any suitable material may be used to form the structural component 622, for example high- density polyethylene [HDPE] extruded in a conventional manner, through a suitably formed tip and die arrangement. Although not shown in this example, one or more longitudinal strength members can be integrated into the structural component 622 during extrusion. It will be understood that this structural component 600 can be formed in unlimited lengths, in advance of assembling any particular cable assembly.

[0032] The outer portions 622a of the structural component partially enclose two cavities that extend in parallel along the length of the cable assembly, separated by the connecting portion 622b. The first cavity 626 houses one or more of the preterminated cable units, including for example cable unit 102. The second cavity 628 houses one or more further ones of the preterminated cable units, including for example the cable unit 102'. The illustration shows two cable units 102 and 102' overlapping in the same portion of the overall length of the cable assembly, purely for ease of understanding. Whether or not they overlap in practice will depend upon the application.

[0033] It will be understood that the diameter of the cable units will be greater at locations where one of the connectors 114, 116 is to be found. This larger dimension of connector 114, 116 is illustrated in broken lines, by way of illustration.

[0034] As mentioned, in this example, the cavities 626 and 628 are only partially enclosed, because the structural component 622 on each side is formed with a longitudinally extending opening 622c. The outer portions 622a of the structural component are deformable to allow these openings to be widened to admit the preterminated cable units and the connectors so that they can be stowed and / or removed without cutting material of the shell. (For the avoidance of doubt, this does not exclude that the material of the shell is cut as part of its initial manufacturing process. See examples below.]

[0035] It is a matter of design choice, whether the cable units 102 and the connectors 116 / 114 can be accommodated entirely within the cavities without deformation of the outer portions 622a, or whether the outer portions remain deformed, at least in the portions of the length where the connectors 114 / 116 are housed. That is to say, it is an option to make a cable assembly with a uniform cross-section along its entire length, or to make it with a more compact cross-section than the one illustrated in Figure 2, but allow the shell to bulge, in portions where a connector 114 / 116 is accommodated. It is also to be understood that the term "cavity" is used herein to refer to any space in which the preterminated cable units can be securely accommodated, and does not imply any particular degree of enclosure. The space forming the "cavity" may be completely surrounded by the structural component, or more than 50% surrounded. In Figure 2, an outer wrap or binding 640 is indicated in broken lines, that can be added around the whole cable assembly, or at selected portions, for example to retain the connectors. Depending on the dimensions of the opening and the stiffness of the material forming the shell, the connectors and / or the lengths of cable units may be held sufficiently tightly that the cable units are captive and further binding is not required, or is only required in a limited form. For some applications, it will be convenient if the cable units and connectors are held relatively loosely within the supporting structure. This may be the case, for example where the cable assembly will be installed in a duct. In such a case the cable units and connectors may be held loosely enough that their ends can be withdrawn from the cavities 626, 628 simply by pulling on the cables 102, 102' at an access point some distance from the original location of the connector 114 / 116, rather than "peeling" it sideways through the side opening.

[0036] In principle, the cavity where the cable units are held could be a relatively shallow recess, where the cable units are less than 50% surrounded. In such a case, additional binding, sheathing or even adhesive may be deployed along some or all of the length of a cable unit, to keep it in place.

[0037] Referring again to Figure 2, it will be seen that cable assembly 600 further accommodates at least one functional cable element 630 within the supporting structure, in addition to the preterminated cable units. The functional cable element 630 may extend along the entire overall length of the cable assembly. In this example, a third cavity 632 is formed integrally with the connecting portions 622b of the structural component 622 and the functional cable element 630 lies within the third cavity. To manufacture such a product, the functional cable element may be fed through the extrusion head at the time of making the structural component 622, or it may be inserted afterwards, for example by pulling, or blowing or any suitable method.

[0038] Purely for the sake of example, the functional cable element 630 in this example is illustrated as a conventional "loose tube" type of fibre optic cable. As is well known, such a cable includes a number of unit tubes containing optical fibres (and optionally electrical conductors] arranged around a central strength member, all surrounded by an extruded sheath. The skilled person will recognise that the various cable elements are not drawn to scale, in this or any other drawing.

[0039] As mentioned already, the lengths and the configuration of cable units can be tailored to every individual installation. It may be noted that the external cavities 626 and 628 need not contain preterminated cable units at all points along their length. There may be portions of the overall length in which only a functional cable element 630 is carried. Likewise, there may be portions of the overall length in which the third cavity 632 is empty.

[0040] It will be seen that the structural component 622 in the example cable assembly 600 effectively comprises an extruded shell structure in which a plurality of cavities are defined by cavity walls and connecting portions in a continuous profile. Some of the cavities are only partially enclosed and accessible from outside the cable assembly (deforming the shell if necessary to open the cavity]. These cavities may be referred to as external cavities in which at least a subset of the series of preterminated cable units are housed. Other cavities such as third cavity 632 may be fully enclosed, and may be referred to as internal cavities. It may be advantageous if the cable units and connectors are held relatively loosely within the cavities 626, 628, as already discussed above.

[0041] Figure 3 illustrates a further example cable assembly 700. Features in Figure 3 have the same reference numbers as in Figure 2, but with prefix '7' instead of '6'. Although it has a different shape, in concept, cable assembly 700 has the same general form and function as cable assembly 600, and it has two external cavities 726 and 728. The main difference in this example is that it has not one but six internal cavities 732.

[0042] This example illustrates how, in a given cable assembly, an internal cavity may be left empty (as at the top left], or it may be used to house a functional cable element. In some of the cavities, it will be seen that a microduct 734 is contained within the cavity as another example of a functional cable element. The term "microduct” in this context refers to any small conduit, for example having an outer diameter 16 mm or less. Typical microduct sizes include 7 / 4 mm and 5 / 3.5 mm, where the first number represents the outer diameter and the second number represents the inner diameter of the microduct. In the illustrated example cable assembly 700, all of the four microducts 734 at the same inner and outer diameter. Depending on the application, different microduct sizes may be included in the cavities, and the cavities themselves may have different sizes to accommodate different functional cable elements. The microducts 734 may be inserted through the extrusion head in the process of forming the structural component 722. Such a form of product and its method of manufacture can be similar to well-known tube bundle products, available from the present applicant and others. In the illustrated example, the microducts 734 at upper middle and upper right carry miniature optical fibre cables 736. These miniature cables may be installed in the microducts after manufacture of the structural component 722, for example by blowing, or they may be contained already in the microducts at the time of manufacturing the tube bundle.

[0043] Finally, the bottom middle cavity 732 is shown housing a cable 738 on its own, without a microduct. This is another example of a functional cable element and, purely for the sake of example, it is illustrated in this case as an insulated electric cable having three conductors. As mentioned already, any or all of the cable units and / or functional cable elements in the cable assembly may contain only optical conductors, only electrical conductors, or a mixture of optical and electrical conductors in the same cable element.

[0044] Figure 4 illustrates a modified cable assembly 700', in which structural component 722' is similar to the structural component 722 of Figure 7 but has a modified cross section. The internal cavities 732' are shown empty for simplicity, but may be populated by various functional cable elements in the same manner as illustrated in Figure 3. In this example, the various portions 722a' and 722b' are formed so that the openings of the "external" cavities 726' and 728' are held closed by the stiffness of the connecting portions 722b' as seen in Figure 4 (a). Then, to insert or withdraw a cable unit 102 / 102', the shell portions are prised apart to form an opening 722c', as seen at the left-hand side in Figure 4 (b) . After insertion, the shell closes again to contain the cable unit securely, as seen on the right-hand side. The opening may stay partly open, in the region of the connectors 114, 116, depending on the relative size of the connectors and the cavities. The opening may even stay partly open along the whole length of a cable unit, depending on the relative size of the cables and the cavities.

[0045] Rather than being extruded with longitudinal openings, a structural component 722’ such as the one illustrated in Figure 4 could be extruded, and then cut longitudinally to form openings 722c. In either case, it may be advantageous for the dimensions and stiffness of the shell to be such that the ends of a cable unit (including any connector) can be withdrawn by pulling on the cable unit at a midway access point, rather than being "peeled" out through the side opening. MANUFACTURE OF THE CABLE ASSEMBLIES

[0046] Advantageously, the cable assemblies (100, 600, 700, 700’] can be made by first preparing a series of preterminated cable units 102, 102' (jumper cables] by cutting appropriate lengths of cable and fitting each one with a first connector 114 at a first end and a second connector 116 fitted at a second end. After the cable units are all prepared, the method continues with arranging the series of preterminated cable units within a supporting structure in such a way that successive cable units extend over different successive portions LI, L2, ...Ln of an overall length Lo of the cable assembly, as described above.

[0047] For examples having functional cable elements (130, 630, 734, 736, 738], these may be assembled within the supporting structure before the series of preterminated cable units are added. One or more functional cable elements may be incorporated within the supporting structure during extrusion of the structural element 622, 722, 722'. In examples where a functional cable element comprises a microduct (734], optical and / or electrical conductors (736, 738] may be installed within said microduct before or after the series of preterminated cable units are added. The microduct may be incorporated within the supporting structure as part of an extrusion step that forms the structural component.

[0048] Cable assemblies of the type described above can be used to facilitate the deployment of network connections throughout a neighbourhood area. A typical application is to create a distribution network providing optical fibre broadband connections to homes and / or business premises in a neighbourhood. As mentioned already, this is only one application example, and the method illustrated is readily adaptable to the distribution of communications and / or power signals to a wide variety of drop terminals. Particular examples include, for example, 5G or Wi-Fi access points. Likewise, instead of a neighbourhood of individual user premises, the methods can be adapted for the distribution of communications and / or power signals over an industrial or academic campus, and within large internally within multi-dwelling residential buildings. As mentioned above, the cable assembly can be installed along a desired route. This route may extend above and / or below ground, and the drop terminals may be located below ground, at ground level or at an elevated position on a utility pole, on a building facade, or within a utility space internal to a building. The preterminated cable units 102, 102' can be used to make local connections between drop terminals along the route. The functional cable element 1 0may simply extend the full length of the route, or it may be broken out in the vicinity of a terminal somewhere along the route. Considering as examples the forms of cable assembly illustrated in Figures 2 and 3, this breaking out operation may involve cutting the structural component 622, 722 to gain access to the functional cable element within. Where the functional element is a microduct 734, this microduct can be cut or branched out of the supporting structure. Where a conduit such as a microduct is broken out, additional lengths of conduit may be used to protect the cable between the cable assembly and the terminal.

[0049] From this discussion, the skilled person will understand that a cable assembly of the general type disclosed herein enables a wide variety of convenient methods to distribute optical communications, electrical communications, and / or electrical power in a wide variety of network configurations. So that optical different optical signals can be used to supply different subsets of the user terminals throughout the network, maintaining signal quality.

[0050] CONCLUSION

[0051] Cable assemblies of the general type disclosed herein enable deployment in a flexible manner, and with a very low cost and easily manufactured cable assembly. Such cable assemblies can be manufactured using conventional techniques and standard components, while being prefabricated in an arrangement that is completely customised to a given deployment project. Depending on the construction, such cable assemblies can be laid along the desired route by direct burying, and / or pulling through pre-installed conduits. Such cable assemblies can be installed aerially, between utility poles, and / or fixed to building facades, and / or within utility spaces of larger buildings.

[0052] While cable units in the examples above have been preterminated cable units, the principles disclosed above can also be applied to an assembly in which some or all of the cable units are not preterminated. The cable ends in that case can be bare or fitted with some protection. Suitable connectors can be fitted after the ends are broken out.

[0053] While specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention, defined by the appended claims and their equivalents. It will also be appreciated that features from these different examples can be combined in many different ways to create further embodiment of the invention. Some of these combinations are explicitly mentioned above, while others will be readily envisaged.

Claims

CLAIMS1. A cable assembly (100, 600, 700, 700’] comprising a supporting structure [120], wherein the supporting structure includes a structural component (622, 722, 722’] that comprises an extruded plastic shell structure in which a plurality of cavities are defined by cavity walls and connecting portions in a continuous profile, the plurality of cavities including a partially enclosed first external cavity (626, 726] and one or more further cavities (628, 728, 632, 732], and wherein a plurality of cable units (102] are housed within the first external cavity, the or each cable unit comprising a length of cable having a first end and a second end, the plurality of cable units being arranged in such a way that different cable units extend over different portions (LI, L2, ...Ln] of an overall length (Lo] of the cable assembly.

2. A cable assembly as claimed in claim 1 wherein at least one of said further cavities is a fully enclosed internal cavity (632, 732] and wherein at least one functional cable element is enclosed within the at least one internal cavity.

3. A cable assembly as claimed in claim 2 wherein at least one said functional cable element comprises at least a microduct [734],4. A cable assembly as claimed in claim 3 wherein, prior to deployment of the cable assembly, said microduct is pre-populated with optical and / or electrical conductors (736, 738],5. A cable assembly as claimed in any preceding claim wherein the or each said external cavity is formed with a longitudinally-extending opening such that the preterminated cable units can be inserted and / or removed without cutting the structural component.

6. A cable assembly as claimed in claim 5 wherein the structural component has deformable portions so that the longitudinally-extending opening can be widened to allow the connectors of the cable units to pass into the first cavity.

7. A cable assembly as claimed in claim 6 wherein, at least in the vicinity of the first and / or second connector, the longitudinally-extending opening remains in a widened state, while the cable units are housed within the cavity.

8. A cable assembly as claimed in any of claims 1 to 7 wherein at least one of said further cavities is a partially enclosed second external cavity (628, 728) that extends within the structural component in parallel with the first external cavity and wherein the shell of the cable assembly at least partially encloses said second external cavity and houses one or more further cable units (102') .

9. A cable assembly as claimed in claim 8 wherein the first and second external cavities are arranged on opposite sides of the supporting structure.

10. A cable assembly as claimed in claim 9 wherein at least one said cable unit of the one or more cable units includes one or more optical fibres, each optical fibre being usable for carrying optical signals between the first end and the second end of said at least one cable unit.

11. A cable assembly as claimed in any preceding claim wherein at least one said cable unit of the one or more cable units includes at least one electrical conductor for carrying power and / or electrical signals between the first end and the second end of said at least one cable unit.

12. A cable assembly as claimed in any preceding claim wherein the cable units housed within the first external cavity provided include one or more preterminated cable units, each preterminated cable unit having a first connector fitted at its first end and / or a second connector fitted at its second end.

13. A cable assembly as claimed in claim 12 wherein the first and / or second connector of said at least one cable unit are at least partially received within the first external cavity.

14. A cable assembly as claimed in any preceding claim wherein said cavities include more than one fully enclosed internal cavity (632, 732), and wherein a plurality of functional cable elements are enclosed within respective ones of said internal cavities.

15. A cable assembly as claimed in claim 14 wherein said plurality of functional cable elements include a plurality of microducts, wherein at least one of said microducts is prepopulated with optical and / or electrical conductors (736), and wherein at least another one of said microducts (734) is empty for receiving optical fibres and / or electrical conductors at a later time.

16. A cable assembly as claimed in any preceding claim wherein at least one said internal cavity is pre-populated with optical and / or electrical conductors (630, 736, 738).

17. A cable assembly as claimed in any preceding claim wherein said structural component incorporates a strength member (724) for transmitting tensile forces during installation of the cable assembly.

18. A method of manufacturing a cable assembly (100, 600, 700, 700',), the method comprising the steps:(a) providing one or more preterminated cable units (102, 102'), each cable unit comprising a length of cable having a first end and a second end;(b) providing a structural component that comprises an extruded plastic shell structure in which a plurality of cavities are defined by cavity walls and connecting portions in a continuous profile, the cavities including a partially enclosed first external cavity (626 / 628, 726 / 728) and at least one fully enclosed internal cavity (632, 732) wherein at least one functional cable element is enclosed within the at least one internal cavity before the performance of step (c); and(c) arranging the one or more of said cable units within the first external cavity supporting structure in such a way that different cable units extend over different portions (LI, L2, ...Ln) of an overall length (Lo) of the cable assembly.

19. A method as claimed in claim 18 wherein said at least one functional cable element comprises at least a microduct (734).

20. A method as claimed in claim 19 further comprising installing optical and / or electrical conductors (736, 738) within said microduct before or after the series of preterminated cable units are added in step (c).

21. A method as claimed in claim 19 or 20 wherein said the method further comprises a step of forming the structural component by extrusion before the series of preterminated cable units are added in step (c), and wherein said microduct is incorporated within the structural component as part of the extrusion step.

22. A method as claimed in any of claims 19 to 21 wherein at least one of the cable units provided in step (a) is a preterminated cable unit having one or both of a first connector (114) fitted at its first end and a second connector (116) fitted at its second end.

23. A method as claimed in claim 22 wherein in step (c) the first and second connectors are at least partially received within the first external cavity.

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