AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION INVENTION TITLE: AN ISOLATION MEANS FOR A DISTRIBUTION BOARD The following statement is a full description of this invention, including the best method of performing it known to us: Ini / c, I I8311 cover sheet doc, 1 AN ISOLATION MEANS FOR A DISTRIBUTION BOARD FIELD OF INVENTION The present invention is related to an isolator, which may be particularly useful for a distribution board. 5 BACKGROUND OF THE INVENTION Previously, distribution boards have been used to distribute electricity from a mains supply to a plurality of subsidiary electrical circuits. In one example, a main electrical supply is delivered via a bus-bar to the distribution board, whereupon the distribution board divides the electrical power feed into the subsidiary circuits, while 10 providing a protective fuse or circuit breaker for each circuit. The distribution board, protective fuses and circuit breakers are usually positioned within a common enclosure. A distribution board may also be known as: a breaker panel, a fuse box, a fuse board, a circuit breaker panel, a consumer unit (or CU), a panel board, a load centre or a 15 power breaker. In typical usage, an electrical device taking power supply from a subsidiary circuit of a distribution board, will attach to a terminal for one of the subsidiary electrical circuits. The terminal may also be known as an electrical connector, a Tee-off or a connection tag. 20 The subsidiary electrical circuits of a distribution board are generally placed in two columns. The circuit panels are "dead front", which means that an operator of the circuit should not be able to contact live electrical parts. Contact of live parts is usually prevented by enclosing the distribution board in a box, which may have a lockable cover. However, when the cover of the box containing the distribution 25 board has been removed, some cables or terminals may be exposed and can pose a danger from electrocution. 12/5/Ah-1831a - pcci-rcv-ny2JO-pcsdow.2 -2- A consumer type distribution board may have only a single horizontal row of fuses or terminals. Larger commercial, public, and industrial installations may use three phase supplies, where a distribution board, for example, has twin vertical rows of terminals. Larger installations will often use subsidiary distribution boards, which are 5 supplied with electrical power from one or more of the subsidiary circuits from the main distribution board. In multiple phase systems, for each phase, power is fed along a bus-bar into the distribution board. In such a system, the distribution board splits the power supply from each phase into a number of subsidiary circuits. In a three-phase system the 10 distribution board divides each phase into multiple subsidiary circuits, where a subsidiary circuit of the first phase (IP) is adjacent a subsidiary circuit of the second phase (2P) which is adjacent a subsidiary circuit of the third phase (3P). This arrangement is then repeated in series, such that a column of the distribution board may consist of a series of subsidiary circuits in a IP, 2P, 3P, IP, 2P, 3P. . . etc. 15 pattern. A distribution board can distribute electrical supply from multi-phase systems incorporating two, three, four or even more phases. Alternatively, a distribution board may distribute electricity in a single phase. A subsidiary electrical circuit from a distribution board feeds, via a terminal, into an 20 electrical device, such as a circuit breaker or an RCBO. Other electrical devices such as transformers or contactors (relays) may also be used. One potential danger with a distribution board is that, when an electrical device is pulled away from the distribution board, the terminal may be electrically live. If a terminal is directly contacted by a person, or indirectly contacted by the person via 25 an electrically conducting tool, such as a metal spanner, the person may be electrocuted. Where there is a large voltage in the subsidiary circuit, electrocution may lead to immediate death. 12/05/10.dh-18311 - speci-rcvmay20o - pcsdoc.3 -3- A further problem with distribution boards is that, for safety, it is often a requirement to switch the entire distribution board in order to carry out maintenance or other work on even a single subsidiary circuit of the distribution board. In some situations, for example where a distribution board is supplying power to a number of electrical 5 or electronic devices in an important information technology installation, having to switch off the entire distribution board in order to work on a single subsidiary circuit may be a great and costly inconvenience. Accordingly, it would be advantageous to provide a device and/or method for increasing safety when disconnecting electrical or electronic devices from a 10 distribution board. It would also be advantageous to provide a device and/or method which decreases or obviates the need to switch off an entire distribution board when work or maintenance is required on a single subsidiary circuit of the distribution board or an electrical/electronic device associated with a single subsidiary circuit. 15 SUMMARY OF THE INVENTION The present invention provides an isolation means for a distribution board having an electrical supply and at least one terminal, the isolator including a switch, when in an operating position, connecting the terminal and the electrical supply, and a switch lock, including a switch lock actuator, wherein, when the switch lock actuator is in a 20 deployed position, the switch lock is engaged and substantially prevents the switch from being in the operating position, and wherein, when the switch lock actuator is in a retracted position, the switch lock is disengaged and the switch is able to be in the operating position. In an embodiment, the switch lock actuator inter-operates with the switch such that, 25 when the switch lock actuator moves towards the deployed position, the switch is caused to be moved towards a non-operating position. 12/05/1O.dh-18311 - speci-revmay2O 10- pc doc.4 -4- In another embodiment, the switch includes a switch assembly, the switch assembly including a slidable switch member and a contact assembly, wherein the slidable switch member is connected to the contact assembly, such that, when the slidable switch member slides, the contact assembly is caused to move such that the switch is 5 moved towards the operating position. In a further embodiment, when the slidable switch member is caused to slide in a direction, the contact assembly is caused to move in a direction which is substantially perpendicular to the slide direction. In another embodiment, the switch assembly further includes biasing means for 10 biasing the contact assembly away from the operating position. The biasing means may include a spring with one end of the spring against a flange protruding from the isolator body into a slot in the contact assembly and the other end against an upper part of the contact assembly. In yet another embodiment, the contact assembly includes a non-conducting contact 15 assembly body and a contact plate for connecting the electrical supply and the terminal of the distribution board, and wherein the contact plate is moveable relative to the contact assembly body. In a further embodiment, the contact plate is moveable relative to the contact assembly body in a direction substantially parallel to the direction in which the 20 contact assembly is caused to move during operation of the switch. In yet another embodiment, the contact assembly is configured so that the contact plate has a limited length of movement. The configuration for limiting the movement of the contact plate may be implemented by providing a slot in the contact assembly body in which the contact plate is situated. 25 Further, the contact assembly may include biasing means for biasing the contact plate towards an end of the slot, the end of the slot being towards an end of the contact assembly body closest to the terminal and the electrical supply of the distribution 12/05/1O.dh-1831|1 - spci-revmay20 10 - pcs.doc.5 -5board. The biasing means may include two springs, each spring at a side of the contact plate, wherein each spring has one end against a part of the contact assembly body and one end against a part of the contact plate. In another embodiment, the switch lock further includes a first switch lock 5 engagement means located on the switch lock actuator and a second switch lock engagement means located on the contact assembly, wherein, when the switch lock is engaged, the first switch lock engagement means engages with the second switch lock engagement means to prevent the contact assembly from moving and thus preventing the switch from being in the operating position. The second switch lock 10 engagement means may optionally be located on the contact assembly body. In another embodiment, the switch lock actuator is biased to a deployed position. Furthermore, the biasing means for biasing the switch lock actuator may include one or more springs to provide the biasing force. In a further embodiment, the switch lock actuator must be fully retracted before the 15 switch lock can become disengaged allowing the switch to be in the operating position. In yet another embodiment, the switch lock actuator includes an actuating button. The actuating button is configured to protrude externally from the body of the isolator (or the body of the distribution board) when the switch lock actuator is 20 deployed, such that, when an electrical device is connected to the terminal of the distribution board, a part of the electrical device presses against the actuating button causing the switch lock actuator to be retracted and thus causing the switch lock to become disengaged. In an embodiment, the actuating button is substantially rectangularly-shaped and is 25 located on an end of the switch lock actuator. Optionally, the actuating button is formed integrally with the switch lock actuator. 12105/10,dh-183I 1 - speci-rcvmay2010 - pcs.dc.6 -6- In another embodiment, the isolation means (or isolator) further includes a retractable access prevention cover for covering a juncture between the body of the electrical device and the body of the distribution board or the body of the isolation means. The retractable access prevention cover may also be useful for covering at 5 least a part of a terminal of the electrical device. Such a juncture is formed when the electrical device is connected to the distribution board, wherein there may be a small gap between the body of the electrical device and the body of the distribution board or the body of the isolation means. The retractable cover is adapted to cover any gap formed by the juncture such that access to the juncture is substantially prevented. 10 The electrical device may include a terminal attachment securing means for securing the electrical device to the terminal of the distribution board. The terminal attachment securing means may include an electrical device terminal including a screw for securing the electrical device to the terminal of the distribution board. The electrical device may also include a screw access hole. The screw access 15 hole in some electrical devices allows access to the screw even when the electrical device is live, which poses a danger to operators. In an embodiment, the access prevention cover, when deployed, covers the screw access hole, thus providing a safer working environment. A safer operating environment may be provided as an operator may be substantially 20 prevented from inserting an electrically conducting item, such as a screw driver, into the gap where the electrically conducting item may come into contact with the terminal protruding from the distribution board. Furthermore, in this embodiment, the retractable cover may be formed as part of the slidable switch member, wherein, when the slidable switch member is moved to the 25 operating position, the retractable cover is deployed to cover the gap formed between the juncture of the body of the electrical isolator and the body of the distribution board or the body of the isolator. In this embodiment, the retractable cover is retracted when the slidable switch member is moved to a non-operating position. 12/05/10,dh-1831 I1 - spcci-rCvmay2010 - pcs.doc.7 -7- By substantially preventing access to the electrical device terminal attachment securing means when the switch is in an operating position, a person will be unable to readily disconnect the electrical device from the terminal of the isolation means, which would otherwise leave the terminal of the isolation means exposed while 5 electrically live, thus posing a danger from electrocution. Accordingly, in this embodiment, the switch must be in a non-operating position (off) before the electrical device can be disconnected from the distribution board. In a further embodiment, the contact plate may include two or more contact studs, at least one contact stud is placed at opposite ends of the contact plate, such that at least 10 one contact stud contacts a part of the terminal of the distribution board and at least one other contact stud contacts a part of the electrical supply of the distribution board. In yet another embodiment, a part of the terminal, external to the body of the distribution board or the body of the isolator, is adapted to protrude into a receiving 15 terminal of the electrical device. The external part of the terminal may be formed from a flat, rectangular-shaped conducting material. Further, in an embodiment, the switch assembly includes a bi-articulate switch lever having two substantially parallel arms, wherein a first arm of the switch lever is adapted to be inserted into a bore located in the slidable switch member and a second 20 arm of the switch lever is adapted to be inserted into a bore located in the contact assembly, such that, when the slidable switch member slides in a direction, the switch lever causes the contact assembly to move in a direction perpendicular to the slide direction of the slidable switch member. Optionally, the bore in the contact assembly is located in the contact assembly body. 25 For a better understanding of the invention and to show how it may be performed, the embodiments thereof will now be described, by way of non-limiting examples only. I2/05/10.d-1831 - speci-reviny2010- pcs.doc.8 -8- Other systems, methods, features and advantages of the invention will be, or will become, apparent to one which is skilled in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the 5 scope of the invention and be protected by the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of two isolators, in accordance with an embodiment, mounted back-to-back. FIG. I also shows an optional external switch lock mechanism, which is not part of the present invention. 10 FIG. 2a and FIG. 2b are, respectively, a left top perspective view and a right bottom perspective view of an embodiment of a switch lock actuator, including an actuating button. FIG. 3a and FIG. 3b are, respectively, a left top and a right bottom perspective view of an embodiment of a slidable switch member. 15 FIG. 4a and FIG. 4b are, respectively, a left top and a right bottom perspective view of an embodiment of a contact assembly. FIG. 5 is a cut-away perspective view of a distribution board showing two columns of isolators, the isolators arranged in pairs which are mounted back-to-back. FIG. 6, which is similar to FIG. 5, is a cut-away perspective view of the distribution 20 board showing two columns of isolators, the isolators arranged in pairs which are mounted back-to-back. I2105/10,dh-18311 -speci-revmay2010-pcs.doc.9 -9- DETAILED DESCRIPTION OF EMBODIMENTS FIG. I shows two isolators 20 in a back-to-back configuration. Such a configuration enables the isolators to be assembled with other pairs of isolators so as to form two columns of isolators 12 for a distribution board 10 as shown in FIGS. 5 and 6. 5 Each isolator 20 includes an isolator body 50, which, in the present embodiment, is formed from a non-conducting material, such as plastic. It will be understood that, in other embodiments, it is possible to incorporate isolators into a distribution board such that the body of the distribution board forms a body for each isolator. Not shown in FIG. I are terminals 14 of the distribution board 10. Each terminal 14 10 is associated with an isolator 20. Parts of the terminals 14 external to the distribution board 10 are adapted to be connected with an electrical device (not shown in the drawings). Such an electrical device may be a circuit breaker, an RCBO, a transformer or another type of electrical device. The external part of each terminal 14 is formed from a flat, rectangular-shaped conducting material. 15 The distribution board 10 also includes an electrical supply 16 (also not shown in FIG. 1), which, in this embodiment, is a number of bus-bars 18. Multiple bus-bars may provide multiple phase electrical supply. The electrical supply 16 delivers electrical power to each terminal 14 via the corresponding isolator 20. Please refer to FIGS. 5 and 6, which show an embodiment of the present invention, 20 wherein isolators 20 are operating with a distribution board 10. The isolators 20 connecting the electrical supply 16 with the terminals 14. FIG. I also shows an optional external locking means 62, which is not a part of the present invention. The following description of features in FIG. I relates to the embodiment of the 25 isolator 20 shown to the left of FIG. 1. The isolator 20 includes a switch 22, which, - 1 02 /0 5 / I0 d h - 1 8 3 1 1 s p c c i -r e v m a y 2 0 l p c s d o . t O in this embodiment, includes a switch assembly 24. The switch assembly 24 includes a slidable switch member 26 and a contact assembly 36. When the switch 22 is in an operating position, it connects a terminal 14 (not shown in FIG. 1) of the distribution board with an electrical supply 16 (not shown in FIG. 1) 5 of the distribution board such that the terminal is live and can provide electrical power to an electrical device connected to the terminal. In FIG. I the switch 22 is shown in a non-operating position. The isolator 20 also includes a switch lock 32. The switch lock 32 includes a switch lock actuator 28. When the switch lock actuator 28 is in the deployed position (as 10 shown in FIG. 1) the switch lock 32 is engaged and prevents the switch 22 from being in the operating position. When the switch lock actuator 28 is in a retracted position the switch lock 32 is disengaged and the switch 22 is able to be in the operating position. Further, in an optional embodiment, the switch lock actuator 28 inter-operates with 15 the switch 22 such that, when the switch lock actuator 28 moves to the deployed position, the switch 22 is caused to be moved to a non-operating position. In this way, when an electrical device is removed from the distribution board 10 and is no longer connected to the terminal 14, the switch lock actuator 28 will be deployed and cause the switch 22 to be in the non-operating position. This prevents the terminal 20 14 from being electrically live when no electrical device is connected to it. Also in another optional embodiment, when the switch lock actuator 28 is fully, or near fully deployed, the switch lock 32 will be engaged, thus preventing the switch 22 from being in the operating position. The switch lock actuator 28 is biased to a deployed position by biasing means 25 including a springs 48 to provide the biasing force. In the switch assembly 24, the slidable switch member 26 is connected to the contact assembly 36, such that, when the slidable switch member 26 slides in a direction, the 12/05/10.dh-18311 - speci-revmay2010 - pcs.doc.I I - II contact assembly 36 is caused to move in a direction which is perpendicular to the slide direction, such that the switch 22 is moved towards the operating position. The slidable switch member 26 includes a switch handle 64 for easier gripping by an operator of the switch 22. 5 The contact assembly 36 includes a non-conducting contact assembly body 38 and a contact plate 40 for connecting the electrical supply 16 and the terminal 14. The contact plate 40 is moveable relative to the contact assembly body 38 in a direction parallel to the direction in which the contact assembly 36 is caused to move during operation of the switch 22. 10 The switch assembly 24 further includes biasing means for biasing the contact assembly 36 away from the operating position. The biasing means includes a spring 46. One end of the spring 46 abuts a flange 78, the flange 78 protruding from the body 50 of the isolator into a slot 80 in the contact assembly body 38. The other end of the spring 46 abuts an upper part 90 of the contact assembly body 38. 15 The contact assembly 36 is configured so that the contact plate 40 has a limited length of movement as it is located in a slot 42 in the contact assembly body 38. Further, the contact assembly 36 includes biasing means for biasing the contact plate 40 towards an end of the slot 42, the end of the slot 42 being towards an end of the contact assembly body 38 closest to the terminal 14 and the electrical supply 16 of 20 the distribution board 10. The biasing means includes two springs 44, each spring at a side of the contact plate 40, wherein each spring 44 has one end against a part of the contact assembly body 38 and one end against a part of the contact plate 40. The switch lock actuator 28 includes an actuating button 30, which protrudes externally from the body of the isolator 50 (or, in some embodiments, the body of the 25 distribution board) when the switch lock actuator 28 is deployed, such that, when an electrical device is connected to the terminal 14, a part of the electrical device presses against the actuating button 30 causing the switch lock actuator 28 to be 1 2/05/1O.dh-18311 - speci-revmay20 IG -pcsdoc.12 - 12 retracted and thus causing the switch lock 32 to become disengaged. In this embodiment, the actuating button 30 is substantially rectangularly-shaped and is located on an end of the switch lock actuator 28, and the actuating button 30 is formed integrally with the switch lock actuator 28. 5 The isolator 20 further includes a retractable access prevention cover 52 for covering a juncture between the body of an electrical device and the body of the isolator 50 and/or for covering at least a part of a terminal of the electrical device. The retractable cover 52 is formed as part of the slidable switch member 26, wherein, when the slidable switch member 26 is moved to the operating position, the 10 retractable cover 52 is deployed to cover the gap formed in the juncture between the body of the electrical device and the body of the isolator 50. In this embodiment, the retractable cover 52 is retracted when the slidable switch member 26 is moved to a non-operating position. The contact plate 40 includes two contact studs 54, each contact stud is placed at 15 opposite ends of the contact plate 40, such that one contact stud 54 contacts a part of the terminal 14 of the distribution board 10 and the other contact stud 54 contacts a part of the electrical supply 16 of the distribution board 10. The switch assembly 24 includes a bi-articulate switch lever 56 having two substantially parallel arms, wherein a first arm of the switch lever is adapted to be 20 inserted into a bore 60 located in the slidable switch member 26 (see FIGS. 3a and 3b) and a second arm of the lever 56 is adapted to be inserted into a bore 58 located in the contact assembly 36 (see FIGS. 4a and 4b), such that, when the slidable switch member 26 slides in a direction, the lever 56 causes the contact assembly 36 to move in a direction perpendicular to the slide direction of the slidable switch member 26. 25 In this embodiment, the bore 58 is located in the contact assembly body 38. Also shown in FIG. I are locking tabs 66 for locking connection to the distribution board 10. This facilitates the assembly of a number of isolator pairs on the distribution board to form columns of isolators 12 as shown in FIGS. 5 and 6. 12/05/10.dh.18311 - speci-revmay2010 - pcs.doc,13 - 13 - FIGS. 2a and 2b show different perspective views of the switch lock actuator 28, according to an embodiment of the present invention. The switch lock actuator 28 includes the actuating button 30, which protrudes externally from the body of the isolator when the switch lock 32 is engaged or moving towards being engaged. 5 The circular protrusion 88 on the switch lock actuator 28 is for securely accommodating one end of the spring 48, being the biasing means for the switch lock actuator. FIG 3a shows an embodiment of the slidable switch member 26, including the access prevention cover 52. The slidable switch member 26 also includes a handle pillar 68 10 for supporting the handle 64 of the slidable switch member 26. FIG 3b shows a different view of the slidable switch member 26 from that shown in FIG 3a. The slidable switch member 26 includes a stopper step 73 for preventing the slidable switch member 26 from being slid too far. When moving the slidable switch member 26 towards the operating position, the stopper 73 eventually comes up 15 against the body 50 of the isolator 20, which stops the slidable switch member 26 from being slid any further. The slidable switch member 26 includes a bore 60 which accommodates one of the two parallel arms of the bi-articulate lever 56. FIGS. 4a and 4b show a detailed view of the contact assembly 36, including the 20 contact assembly body 38 and the contact plate 40, which is accommodated in the slot 42 in the contact assembly body 38. The two springs 44 are for biasing the contact plate 40 towards an end of the slot 42 which is towards an end of the contact assembly body 38, when the isolator 20 is operating with the distribution board 10, closest to the terminal 14 and the electrical supply 16. 25 The contact assembly body 38 also includes a circular protrusion 49 located towards the top end of the slot 80 in the contact assembly body. The circular protrusion 49 is for securely accommodating one end of the biasing means provided by the spring 46. 12/05/10.dh-183|1 - speci-rewmay2010 -pcs.doc.14 - 14 - The bore 58 in the contact assembly body 38 accommodates one of the parallel arms of the bi-articulate lever 56. In this embodiment of the isolator 20, the switch lock 32, includes a first switch lock engagement means 84, which is located on a flange 86 projecting from an end of the 5 switch lock actuator 28 (see FIGS. 2a and 2b), and a second switch lock engagement means 82, which is located towards a top part of the contact assembly body 38. When the first switch lock engagement means 84 engages with the second switch lock engagement means 82, the switch lock 32 is engaged and prevents the contact assembly 36 from moving towards the operating position. 10 FIG. 5 shows an embodiment of the invention including a plurality of isolators 20 arranged in two columns 12. The isolators 20 are in a distribution board 10 which includes an electrical supply 16 and terminals 14. Each terminal 14 corresponds with an isolator 20. In the distribution board 10 depicted in FIG. 5, the electrical supply 16 includes four 15 (4) bus bars 18. Each back-to-back isolator pair is connectable with the electrical supply 16 via a supply terminal 19. In this embodiment, in each isolator the contact plate 40 of the switch 22 electrically connects the supply terminal 19 and the terminal 14 of the distribution board 10. FIG. 5 also shows an embodiment of component parts of the switch 22 including a 20 switch assembly 24, which includes a slidable switch member 26 and a contact assembly 36. The terminals 14 may also be provided with removable covers 87, which may allow further protection against electrocution. In FIG. 5, the front-most left isolator 20 is shown in a non-operating configuration, 25 wherein the switch lock actuator 28 is in a deployed position, the switch lock 32 is engaged and the switch 22 is substantially prevented from moving to an operating position. 12/05/1O,dh.1831 I -speci-rcvmay2O1O -pcsdoc.15 - 15 - The front-most right isolator 20 is shown in an operating configuration, wherein the switch lock actuator 28 is in a retracted position (this would typically be effected by a part of an electrical device pushing against the switch lock actuator when the device is connected to the terminal 14), the switch lock 32 is disengaged and the 5 switch 22 has been allowed to move towards, and is depicted as being in, an operating position, wherein the contact plate 40 electrically connects the electrical supply 16 (via the supply terminal 19) and the terminal 14 (external to the distribution board 10). FIG. 6 is a similar view to FIG. 5 with more features of the distribution board 10 removed from the depiction allowing a clearer view of an optional arrangement of the terminals 14 and the supply terminals 16. The invention is susceptible to variations and/or modifications and/or additions other than those specifically described, and it is to be understood that the invention includes all such variations and/or modifications and /or additions, which fall within 15 the scope of the following claims. It will be understood that in two or three phase systems, the terminals 14 and supply terminals 19 of each phase may be arranged on a distribution board 10 in an alternating pattern. Accordingly, the isolators 20 associated with each phases terminals 14 are positioned in a corresponding alternating arrangement such that a 20 first phase isolator 20 is positioned adjacent a second phase isolator 20 and, in a three phase arrangement, a second phase isolator 20 is positioned adjacent a third phase isolator 20. In such arrangements, there may be provided a two phase switch handle and/or a three phase switch handle which connects the switches 22 of each first, send and, in the three phase arrangement, third phase isolator, and which is advantageous 25 for simultaneous switching of the isolators in a two or three phase system. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or 12/05/10,dh-1831 I - spcci-rcvmay2010 - pcs.doc,16 - 16group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form or suggestion that the prior art forms part of the 5 common general knowledge in Australia. 12/05/10.dh-18311 - spcci-revmay20 10 - pcsdoc. 17 - 17-