referring to fig1 and 2 a , the housing 4 is of a substantially rectangular configuration that is divided into ten cable - receiving chambers 10 with dividing walls 12 projecting therefrom . the walls 12 have longitudinally - aligned apertures 14 through which an upper support shaft 16 passes for mounting components of the arrangement as hereinafter described . two conductive , copper , bars 18 ( fig2 b ) are secured longitudinally within the plastic housing 4 and extend through each of the chambers 10 , as can be seen in fig7 and 8 . the bars 18 comprise the busbars of the arrangement 2 . as can be seen from fig1 and 2 a , each chamber 10 of the housing 4 has an aperture 20 in the side wall thereof for receiving the stripped end of an electrical cable . since each of the tap ports 8 and associated chambers 10 separated by a pair of dividing walls 12 are identical , the following description will be made in respect of a single set of these components . referring to fig3 and 2 c , a short shaft 22 , extending transversely to the conductive bars 18 , is located in the housing 4 at the lower end of the chamber 10 , and serves to retain the lower end 24 of a tension spring 26 , whose upper end 28 engages the aperture 29 of a support plate 30 , the plane of which lies substantially parallel to the aperture 20 of the chamber 10 . although as shown in fig2 c , the upper end of the support plate 20 is bent over to form a hook 32 , a preferred embodiment of the support plate is shown at 34 in fig2 d , which instead has an aperture 36 at its upper end beyond a pair of shoulders 37 , beyond its aperture 38 . a cable holder 40 , shown in detail in fig2 e , is slidably mounted within the chamber 10 and has a generally u - shaped upper channel 42 that can be aligned with the support plate aperture 38 and the housing aperture 20 for receipt of an electric cable 43 transversely therein ( see fig7 and 8 ). the cable holder 40 also has a pair of downwardly - extending lower channels 44 for receiving respective ones of the busbars 18 of the arrangement 2 ( see fig7 and 8 ). a dividing wall 46 that extends longitudinally of the housing 4 , is slotted at 47 to receive the support plate 34 slidably therewithin . the upwardly - extending side walls of the cable holder 40 have respective oval apertures 48 , by means of which the cable holder 40 is mounted on the longitudinally - extending upper shaft 16 of the housing 2 as hereinafter described . the facing inner surfaces of the cable holder 40 adjacent the apertures 48 are each provided with a pair of stops 50 , 52 for the purpose discussed below . the final component within each chamber 10 of the arrangement 2 is a switching member 54 ( shown in detail in fig2 f ) that has a pair of spaced apart limbs 56 at one end that are apertured so as rotatably to mount the member 54 on the upper housing shaft 16 . a cam 58 extends outwardly from each of the limbs 56 for engagement within the apertures 48 of the cable holder 40 . as mentioned above with reference to fig1 , the left hand port 6 of the arrangement 2 is for receipt of a feeder cable , and as such the contents of its chamber 10 differ from that of the chambers 10 of the tap ports 8 . a feeder cable connection device 60 , shown in detail in fig2 g comprises a metal body 62 that contains a compression spring 64 at its lower end . a shear head screw 66 is threadedly engaged at the upper end of the device 60 and is connected to an inner pressure plate 68 . with the connection device 60 retained within the insulating housing 4 , a feeder cable can be introduced through the feeder port aperture 20 , so as to extend through the body 62 , wherein it is tightened by means of the screw 66 and pressure plate 68 against the spring 64 . after the connection is made , the screw 66 may be covered by a protective insulating cap 67 . the device 60 is located transversely in the housing 4 between the busbars 18 , and this tightening action not only secures the feeder cable within the device 60 , but also ensures good electrical contact , against the returning action of the spring 64 , of the feeder cable onto the pair of spaced apart busbars 18 . fig2 h shows a modification of the feeder cable connection device 60 , wherein the resilience for retaining the cable is provided by flexibility of the body of the device 70 . in operation of the switchable electrical interconnection arrangement , a feeder electric cable is stripped of its insulation at one end , and the bare conductor is inserted into the aperture 20 of the port 6 so as to pass through the body 62 of the connecting device 60 . the screw 66 is tightened up to its shear point , thereby ensuring good electrical connection between the feeder cable and the pair of busbars 18 . whilst a branching tap cable may be connected into its aperture 20 of the tap port 8 with its switching member 54 in the on or off position , connection is preferred , for safety reasons , to be made with it in the off position , abutting the stops 52 of the cable holder 40 . in this position , as shown in fig6 and 7 , the cams 58 of the switching member 54 , which extend into the apertures 48 of the cable holder 40 , have raised the cable holder 40 such that the upper shoulders thereof project above the upper surfaces of the projections 12 , and the branch cable channel 42 is in a raised position . the support plate 34 may then be raised , by means of its aperture 36 , for example by levering a screwdriver over the top of the housing 4 above the aperture 20 , against the resistance of the spring 26 , so as to dispose the support plate aperture 38 in alignment with the housing aperture 20 and with the channel 46 . in this position , the stripped end of a tap cable conductor 43 can be inserted so as to lie along the channel 46 of the cable holder 40 . release of the screwdriver then allows the support plate 34 to return downwards under the action of the spring 26 until the tap conductor 43 in the channel 42 is urged against the cable holder dividing wall 46 ( see fig7 ). thus , in this position the tap cable is mechanically securely retained within the housing 4 and is electrically separated from the busbars 18 . in order to make electrical connection between the branch cable and the busbars 18 , and thus with the feeder cable , the switching member 54 is moved over from the off position shown in fig7 , to the on position shown in fig8 , abutting the stops 50 of the cable holder 40 . owing to the eccentric mounting of the cams 58 within the oval apertures 48 of the cable holder 40 , this movement allows the support plate spring 26 to pull both the support plate 34 and the cable holder 40 downwardly in the tap chamber 10 , and to bring the branch cable 43 lying in the channel 42 of the cable holder 40 down into contact with the pair of busbars 18 , which are now sitting within the channels 44 and straddled by the cable holder 40 . it will be appreciated , that the upper surface of the dividing wall 46 of the cable holder 40 lies below the bottom of the channels 44 thereof , to allow this interengagement , which is enhanced by the return force of the support plate spring 26 , which is still under tension . it will be appreciated that by reversing the movement of the switching member 54 , the cable holder 40 , owing to the movement of the cams 58 within the holder apertures 48 , is again pulled upwards in the chamber 10 until the switching member 54 again abuts the off stop 52 . it will also be appreciated , that each of the nine tap ports 8 may be operated independently of each other , so that appropriate ones of the branch cables 43 may be introduced or removed , and connected or disconnected , independently of the others . fig9 shows a modified switching arrangement 70 , in which ten chambers of the housing 72 are divided into two groups 74 , 74 a of five chambers each . each group 74 , 74 a can receive one feeder cable , for example of different phases , in a respective end port 76 , 76 a and can accommodate up to four branch cables in the remaining ports . the ports and other components of the arrangement 70 may be substantially as described above for the feeder and branch ports respectively of the arrangement 2 . it will be appreciated that the busbars of the arrangement 70 will be approximately half the length of the busbars 18 of the arrangement 2 , since they will be serving respective groups 74 , 74 a of the housing chambers , and will be insulated from each other . it will be appreciated that fewer or more than eight branch ports may be provided by the switchable electrical interconnection arrangement of the invention .