THIS INVENTION relates to the insulation of installations.

The invention is applicable to the electrical insulation of electrical bus bar installations and the thermal insulation of fluid conduits.

In relation to the insulation of bus bar installations the bus bar system is insulated from the frame of the switchboard by the material that supports it which may comprise bakelite sheet or nylon mouldings. The bus bars themselves do not need to be insulated along their length for the system to function however it is desirable that the bars of each phase be individually insulated for their entire length to prevent short circuiting between each of the phases or between each of the bus bars and earth. Such shorting can be caused by tools being left in the installation subsequent to maintenance activities, vermin, dust, moisture and falling components or debris. In the event of shorting, the bus installation can be destroyed together with the associated building or structure. In the light of these dangers it is becoming more common for the bus bars of electrical bus bar systems to be insulated from each other and the earth for their entire length.

Prior methods of insulation have involved P.V.C. dipping, heat shrink sleeving, taping or painting. In effecting the P.V.C. dipping the bars are made assembled, then dismantled, heated and coated with P.V.C. powder to form a full insulation, the excess P.V.C. is trimmed and the bars are finally installed. The difficulty with such an arrangement results from the fact that joints which are bolted cannot be treated because of the impracticality of coating a whole (and often very large) section of bar. In addition it is necessary that the joints be accessible for maintenance.

Insulating by utilising heat shrink sleeving requires that the bars be handled in a similar manner as that used for P.V.C. dipping. The sleeving needs to be selected to suit the size of the individual bar and after it is fitted over the bar, the plastic is shrunk with the aid of a hot air blower. This system is labour intensive and again presents difficulty at joins which cannot be insulated by this method to adequately accommodate for subsequent access.

The taping of bus bars and joints involve wrapping conventional electrical insulation tape around bus bars. Such an arrangement present an ugly appearance and over time the tape unwinds due to the loss of adhesion by the tape as a result of age and heat. The method is also very- labour intensive and presents difficulty in adequately providing for subsequent access to joints and connections.

The insulating of a bus bar system by painting with a desired coating is less labour intensive than the previous methods but presents a difficulty in adequately providing subsequent access to the interconnections and joints of the system and can result in an ineffective insulation under heavy load conditions.

One other means of insulating bus bar systems is disclosed in GB2089585A and comprises a plastic extrusion which is a snap fit over a bus bar. The extrusion protects only one face of the bus bar and because of its rigid nature cannot adapt to bends, corners or junctions between bus bars. In addition each section must be cut accurately to size before being applied and there is no effective means of protecting junctions.

In one form the invention resides in an insulation for fluid conduit and electrical conductor installations comprising a strip shaped flexible covering having insulation properties said covering comprising two portions interconnected by a longitudinal hinge and/or support the outer longitudinal edges of each portion being adapted to be releasably interengaged.

The invention will be more fully understood in the light of the following description of several specific embodiments. The description is made with reference to the accompanying drawings of which:-

Figure 1 is a cross-section of an electrical bus bar having a covering according to the first embodiment mounted thereto;

Figure 2 is an isometric view of the joint having an associated covering according to a second form of the embodiment affixed thereto; and

Figure 3 is a cross-section of a covering according to the third embodiment.

The first embodiment is directed to the insulation of electrical bus bars 11 and comprises a strip shaped extrusion 12 formed from a material having desirable electrical insulating properties and having a channel shaped configuration whereby the sides are substantially parallel and the interconnecting web 13 is enlarged. The sides 12a and 12b are spaced apart by the web 13 to define a space conforming to the cross-sectional configuration of the bus bar 11. The difference in thickness of material between the sides 12a and 12b and the web 13 facilitates a hinge like interconnection whereby each portion is able to flex away from the web without any substantive distinctive of the web. The outer edges of

side 12a and 12b are formed with an inwardly directed rib which accommodates an interengagable locking means 15 to facilitate retention of the two portions 12a and 12b together but subsequent non destruction to provide access into the area defined by the interior. The combined thickness of the ribs 18 and the locking means when interengaged correspond to the spacing of the sides provided by the web 13. The outer face of the web 13 is formed with a longitudinal recess which is capable of retainably receiving an identification beading 16. The beading may be the form of individual beads or a continuous length of beading which conforms to the configuration of the recess 17 provided in the hinged portion 13 to be retained thereby. The beading is coloured or visually modified appropriately to facilitate identification of the bus bar with which the covering 12 is associated. If desired the beading may not be used or provided for. In addition any other form of indicia may be used for engagement in correspondingly shaped recesses on the strip.

In use a length of the covering 12 is cut according to the length of bus bar between two joints to be covered. The portions 12a and 12b are then disconnected by disengagement of the locking means 15 and the covering is mounted over the bus bar 11. Once in place the portions 12a and 12b are re-engaged through the locking means 15 and the appropriate identification beading 16 is inserted into the recess 17 of the hinge portion 13 of the covering. To cover a T-shaped joint a second form of the embodiment of enlarged dimension is used. The joint covering extrusion is cut to length and applied over the joint whereby the web 13 lies against the main bus bar of the junction and the free edges to each side of the connecting bus bar are interconnected at the side thereto.

If desired the covering may be formed of a material which is thermally conductive and the outer surface of the covering may be coloured and configured to facilitate the dissipation of heat from the bus bar through radiation and the like.

Where a joint is to be covered the covering described above is associated with a second embodiment of the invention which can be used as a joint cover. The second embodiment comprises a strip of flexible sheet material 11 whereby edges of the sheet material are adapted to be releasably interengagable with each other. To install the strip material a length is cut which is sufficient to cover the joint and to extend to either side of the joint. The strip material is folded about the central longitudinal axis 23 over the joint as shown at figure 2 whereby the opposed edges abutt with each other and the portions of the opposed edges to each side of the joint are interengaged. One means of effecting releasable engagement between the flexible material comprises the use of "Velcro" loop and pile strips at the opposed edges. It should be appreciated however, that any other suitable form of attachment means may be used.

If desired the second embodiment need not only be used with joints but may be used for the whole bus bar installation.

The third embodiment as shown at figure 3 is of a similar form to the first embodiment and comprises a channel shaped extrusion 112 formed from a material having desirable electrical insulating properties. The enlarged web 113 provides a substantially rigid support between the flexible sides 112a and 112b which can be separated to be engagable over a bus bar. As in the case of the first

embodiment the web 113 spaces the internal faces of the each side 112a and 112b from each other to define a space conforming to the cross-sectional configuration of the bus bar 11. The opposed face of the outer edges 115 of each side is formed with an inwardly directed rib 11 which are provided with interengagement means (not shown) comprising "Velcro" tape or like fixing means which will facilitate the retention of the two side portions 112a and 112b around a bus bar. The combined thickness of the ribs and interconnected means when interconnected corresponds to the spacing provided between the inner faces by the support web 113. The channel shaped extrusion may be suitably coloured to facilitate identification.

The third embodiment is applied in the same manner as the first embodiment and may also extend over the junctions between the bus bar members.

As a result of each of the embodiments an entire bus bar installation can be insulated by means of unskilled labour using a pair of scissors or like cutting means as the tool of trade. Furthermore the embodiments facilitate the maintenance of the bus bar installation without the destruction of the insulation provided by the covering. Furthermore the adaption of the bus bar installation by the inclusion or deletion of components therefrom subsequent to the installation being installed does not result in difficulties when it becomes necessary to resinsulate the bus bar installation after the adaptions have been made.

The embodiment may be readily modified to be used with fluid conduits where it is necessary to insulate against the transfer of heat between the conduit and the surroundings.

It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiment described above. In particular the interengagement between the outer longitudinal edges may take any desired form.