TECHNICAL FIELD

[1] The present invention relates to an electrical testing device. In particular, the present invention relates to a 230V single phase shore polarity and monitoring circuit.

BACKGROUND

[2] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

[3] Shore supply, sometimes also referred to as shore power is the provision of electrical power, normally grid power, to a vessel at berth. Shore supply reduces the reliance on a vessel’s generated power supply.

[4] Having electrical power on vessels can be dangerous, water and electricity don’t tend to mix well. Protection devices such as Residual Current Devices (RCDs), also referred to as 'safety switches' are mandatory on many vessels to prevent electrocution.

[5] For protection devices to work correctly, the active and neutral conductors must be connected correctly. If the active and neutral conductors are reversed the protection devices will not work as designed.

[6] Currently for shore supply, it is required that the polarity is verified as correct during completion testing and that it is signed off by an electrical contactor.

[7] There are polarity testers available to check the polarity of shore supply. These provide an indication only if the polarity is wrong and relies on an operator not to make the connection if the polarity is reversed. These work well, however, they are prone to human error.

[8] Additionally, if a fault is noticed with a polarity tester, the shore supply will need to be rewired by a licenced electrician, resulting in unwanted downtime and maintenance/repair costs.

SUMMARY OF INVENTION [9] In an aspect, the invention provides an electrical testing device comprising: a first conductor; a second conductor; an active conductor; a neutral conductor; an earth conductor; one or more connectors to connect the active conductor, the neutral conductor and the earth conductor to a shore supply; a polarity switch to control a connection between the active conductor and the neutral conductor and the first conductor and the second conductor, the polarity switch changeable between a first condition where the active conductor is connected to the first conductor, and the neutral conductor is connected to the second conductor, and a second condition where the active conductor is connected to the second conductor, and the neutral conductor is connected to the first conductor; a polarity test circuit connected between the first conductor and the earth conductor, the polarity test circuit including a test switch to open or close the polarity test circuit and a test indicator to indicate if the polarity test circuit is energised when the test switch is in the closed position, the polarity test circuit including a first relay connected in series with the test indicator; a supply circuit connected between the first conductor and the second conductor, the supply circuit including a first switch to open or close the supply circuit, a second relay, a second switch in parallel to the first switch, to open or close the supply circuit, and a supply indicator to indicate if the supply circuit is energised, wherein when the first relay is energised, the first relay closes the first switch, energising the supply circuit, and wherein when the second relay is energised, the second relay closes the second switch.

[10] Preferably the electrical testing device further includes a source circuit connected between the first conductor and the second conductor, the source circuit including a source indicator to indicate if the source circuit is energised. [11] Preferably the source indicator indicates if one of the first conductor or the second conductor is energised. Preferably the source indicator is a light emitting diode (LED). In another embodiment, the source indicator is a sensor. Preferably the state of the sensor is displayed on a display. Preferably the display is an LCD display or the like. Preferably the source circuit is connected to the first conductor via a fuse. Preferably the source circuit is connected to the second conductor via a fuse.

[12] Preferably the electrical testing device further includes a supply circuit connected between the first conductor and the second conductor. Preferably the supply circuit includes a first switch to open or close the supply circuit. Preferably the polarity test circuit includes a first relay. Preferably when energised, the first relay closes the first switch. Preferably the supply circuit includes a second switch in parallel to the first switch, to open or close the supply circuit. Preferably the supply circuit includes a second relay. Preferably when energised, the second relay closes the second switch. Preferably the supply circuit includes a supply indicator to indicate if the supply circuit is energised. Preferably the supply indicator is a light emitting diode (LED). In another embodiment, the supply indicator is a sensor. Preferably the state of the sensor is displayed on a display. Preferably the display is an LCD display or the like. Preferably the supply circuit includes a coil. Preferably the coil is connected in parallel to the supply indicator. Preferably the coil is connected in parallel to the second relay. Preferably the supply circuit is connected to the first conductor via a fuse. Preferably the supply circuit is connected to the second conductor via a fuse.

[13] Preferably, the test indicator is a light emitting diode (LED). In another embodiment, the test indicator is a sensor. Preferably the state of the sensor is displayed on a display. Preferably, the display is an LCD display or the like.

[14] Preferably the polarity test circuit is connected to the earth conductor via a resistor. Preferably the resistor is in the range of 1 kO and 50kQ. More preferably, the resistor is a 25kQ resistor. Preferably the polarity test circuit is connected to the first conductor via a fuse.

[15] Preferably the test switch is biased into the open position. Preferably the test switch is a push button type switch. In another embodiment, the test switch is an electrically actuated switch. In another embodiment, the test switch is controlled by a relay. Preferably, the relay is an electromechanical relay. Preferably, the relay is a timer relay. Preferably, the timer relay is connected in parallel with the first relay and the second relay. Preferably, the timer relay is a single pole, double throw relay. In some embodiments, closing of the test switch (timer relay switch) is delayed by an amount of time after the application of the voltage across the terminals of the timer relay. Alternatively, the opening of the test switch is delayed by an amount of time once the application of the voltage across the terminals of the timer relay ceases. In a preferred embodiment, the test switch is programmed to remain on (i.e. closed) for between approximately 5 seconds and 10 seconds before returning to the off (i.e. open) position after the application of the voltage across the terminals of the timer relay.

[16] Preferably the electrical testing device further includes a circuit breaker between the one or more connectors and the first conductor. More preferably the electrical testing device further includes a circuit breaker between the one or more connectors and the active conductor. Preferably the electrical testing device further includes a circuit breaker between the one or more connectors and the second conductor. More preferably the electrical testing device further includes a circuit breaker between the one or more connectors and the neutral conductor. Preferably a circuit breaker is connected between each of the first and second conductor and the one or more connectors. More preferably a circuit breaker is connected between each of the active and neutral conductor and the one or more connectors. In one embodiment the circuit breaker is a protection device. Preferably the protection device is a residual current device.

[17] Preferably the earth conductor, the first conductor and the second conductor are connectable to a main switchboard. Preferably a contactor is connected between the first conductor and the main switchboard. Preferably a contactor is connected between the second conductor and the main switchboard. Preferably the contactor on the first conductor is activated by the supply circuit coil. Preferably the contactor on the second conductor is activated by the supply circuit coil. Preferably when the coil is energised, the contactors are in a closed condition. Preferably when the contactors are in a closed condition the first and second conductors are electrically connected to the main switchboard. Preferably the electrical testing device includes the main switchboard. Preferably when the coil is not energised, and the contactors are in an open condition, no electrical power can flow from the shore supply to the main switchboard. Preferably the main switchboard includes an isolator. [18] Preferably the first relay is a solid state relay. Preferably the second relay is a solid state relay.

[19] Preferably the polarity switch is further changeable to a third position in which the active conductor and the neutral conductor are disconnected from the first conductor and the second conductor.

[20] In another aspect, the present invention broadly resides in a vessel including an electrical testing device comprising: a first conductor; a second conductor; an active conductor; a neutral conductor; an earth conductor; one or more connectors to connect the active conductor, the neutral conductor and the earth conductor to a shore supply; a polarity switch to control a connection between the active conductor and the neutral conductor and the first conductor and the second conductor, the polarity switch changeable between a first condition where the active conductor is connected to the first conductor, and the neutral conductor is connected to the second conductor, and a second condition where the active conductor is connected to the second conductor, and the neutral conductor is connected to the first conductor; and a polarity test circuit connected between the first conductor and the earth conductor, the polarity test circuit including a test switch to open or close the polarity test circuit and a test indicator to indicate if the polarity test circuit is energised when the test switch is in the closed position.

[21 ] Preferably the vessel is a boat or a ship.

[22] In another aspect, the present invention broadly resides in an electrical testing device comprising: a first conductor; a second conductor; an active conductor; a neutral conductor; an earth conductor; one or more connectors to connect the active conductor, the neutral conductor and the earth conductor to a shore supply; a polarity switch to control a connection between the active conductor and the neutral conductor and the first conductor and the second conductor, the polarity switch changeable between a first condition where the active conductor is connected to the first conductor, and the neutral conductor is connected to the second conductor, and a second condition where the active conductor is connected to the second conductor, and the neutral conductor is connected to the first conductor; a polarity test circuit connected between the first conductor and the earth conductor, the polarity test circuit including a test switch to open or close the polarity test circuit and a test indicator to indicate if the polarity test circuit is energised when the test switch is in the closed position, the polarity test circuit including a first relay connected in series with the test indicator; a supply circuit connected between the first conductor and the second conductor, the supply circuit including a first switch to open or close the supply circuit, a second relay, a second switch in parallel to the first switch, to open or close the supply circuit, and a supply indicator to indicate if the supply circuit is energised, wherein when the first relay is energised, the first relay closes the first switch, energising the supply circuit, and wherein when the second relay is energised, the second relay closes the second switch.

[23] Preferably the electrical testing device further includes a source circuit connected between the first conductor and the second conductor, the source circuit including a source indicator to indicate if the source circuit is energised.

[24] In an aspect, the invention provides an electrical testing device comprising: a first conductor; a second conductor; an active conductor; a neutral conductor; an earth conductor; one or more connectors to connect the active conductor, the neutral conductor and the earth conductor to a shore supply; a testing circuit comprising: a polarity switch to control a connection between the active conductor and the neutral conductor and the first conductor and the second conductor, the polarity switch changeable between a first condition where the active conductor is connected to the first conductor, and the neutral conductor is connected to the second conductor, and a second condition where the active conductor is connected to the second conductor, and the neutral conductor is connected to the first conductor; a polarity test circuit connected between the first conductor and the earth conductor, the polarity test circuit including a test switch to open or close the polarity test circuit and a test indicator to indicate if the polarity test circuit is energised when the test switch is in the closed position, the polarity test circuit including a first relay connected in series with the test indicator; a supply circuit connected between the first conductor and the second conductor, the supply circuit including a first switch to open or close the supply circuit, a second relay, a second switch in parallel to the first switch, to open or close the supply circuit, and a supply indicator to indicate if the supply circuit is energised, wherein when the first relay is energised, the first relay closes the first switch, energising the supply circuit, and wherein when the second relay is energised, the second relay closes the second switch.

[25] Preferably, the test circuit is mounted on a printed circuit board (PCB).

BRIEF DESCRIPTION OF THE DRAWINGS [26] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

Figure 1 is a schematic circuit diagram of an electrical testing device according to an embodiment of the present invention;

Figure 2 is a schematic circuit diagram of the device shown in Figure 1 , where the device is in an energised state;

Figure 3 is a schematic circuit diagram of the device shown in Figure 1 , where the device is in an energised state with reversed polarity;

Figure 4 is a schematic circuit diagram of an electrical testing device according to a second embodiment of the present invention;

Figure 5 is a schematic circuit diagram of the device shown in Figure 4, where the device is in an energised state;

Figure 6 is a schematic circuit diagram of the device shown in Figure 4, where the device is in an energised state with reversed polarity; and

Figure 7 is a schematic for a printed circuit board for the automated test circuit shown in Figure 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[27] Figures 1 to 3 illustrate a first embodiment of an electrical testing device 1 for testing the electrical supply and polarity of the circuit providing power to a vessel (such as a boat or a ship at berth, for example).

[28] With reference to Figure 1 there is shown an electrical testing device 1 according to an embodiment of the present invention. The electrical testing device 1 has a first conductor 100, a second conductor 102 and an earth conductor 104, all of which are connected to a main switchboard (MSB) 106. [29] The electrical testing device 1 also includes an active conductor 108 and a neutral conductor 110. The earth conductor 104, active conductor 108 and neutral conductor 110 are all connected to a shore connection 112 which is in turn connected to a shoreside electrical supply.

[30] Connected between the first conductor 100 and the second conductor 102 on a main switchboard side, and the active conductor 108 and the neutral conductor 110 on a shore supply side, is a polarity switch 114 (i.e. a double pole, double throw changeover switch).

[31] The polarity switch 114 controls a connection between the active conductor 108 and the neutral conductor 110 and the first conductor 100 and the second conductor 102 such that the electrical testing device 1 can be in one of two connection configurations: a first connection configuration and a second connection configuration, which will be explained in more detail below.

[32] In the first connection configuration (shown in Figure 2), the polarity switch 114 connects the active conductor 108 to the first conductor 100, and the neutral conductor 110 to the second conductor 102.

[33] In the second connection configuration (shown in Figure 3), the polarity switch 114 connects the neutral conductor 110 to the first conductor 100, and the active conductor 108 to the second conductor 102.

[34] The electrical testing device 1 also includes a double pole circuit breaker CB1 having a first conductor CB and a second conductor CB.

[35] The first conductor CB is connected to the first conductor 100 between the main switchboard 106 and the polarity switch 114. The second conductor CB is connected to the second conductor 102 between the main switchboard 106 and the polarity switch 114.

[36] In addition to the double pole circuit breaker CB1 , the electrical testing device 1 includes a first contactor 117a and a second contactor 117b on the first conductor 100 and the second conductor 102, respectively. Both the first contactor 117a and the second contactor 117b are normally open.

[37] The first contactor 117a is connected to the first conductor 100 between the main switchboard 106 and the first conductor CB. The second contactor 117b is connected to second conductor 102 between the main switchboard 106 and the second conductor CB. [38] The electrical testing device 1 also includes a manual test circuit 116 having a number of sub-circuits.

[39] A first sub-circuit for testing the source takes the form of a source test circuit 118 having a source indicator in the form of a source light emitting diode (LED) 120 connected between the first conductor 100 and the second conductor 102. In use, the source LED 120 indicates if the source test circuit 118 is energised or not. In some embodiments, the source indicator is a sensor and the state of the sensor is displayed on a display (such as a liquid crystal display (LCD), for example).

[40] A second sub-circuit testing polarity takes the form of a polarity test circuit 122 connected between the first conductor 100 and the earth conductor 104. The polarity test circuit 122 includes a switch in the form of a push button 124 to open or close the polarity test circuit 122, a test indicator in the form of a polarity test LED 126 to indicate if the polarity test circuit 122 is energised when the push button 124 is in the closed position and a first relay in the form of a solid state relay (SSR1 ) 128. The push button 124, the polarity test LED 126 and the SSR1 128 are all connected in series with a resistor 130. When the SSR1 128 is energised (through the actuation of the push button 124), an SSR1 switch 134 controlled by SSR1 128 becomes closed (shown in Figure Y). The polarity test circuit 122 is connected to the earth conductor 104 via the resistor 130. The resistor 130 is a 25kQ resistor.

[41] The electrical testing device 1 further includes a third sub-circuit in the form of a supply test circuit 132 connected between the first conductor 100 and the second conductor 102. The supply test circuit 132 includes the SSR1 switch 134 which is controlled by SSR1 128, as described above. The supply test circuit 132 also includes a second relay in the form of a second solid state relay (SSR2) 136. When the SSR2 136 is energised it closes a SSR2 switch 138 (shown in an off or open condition in Figure 1 ) which is connected in parallel with the SSR1 switch 132.

[42] The supply test circuit 132 includes a supply indicator in the form of a supply LED 140 to indicate if the supply test circuit 132 is energised. The supply LED 140 is connected in parallel with the SSR2 138.

[43] The supply test circuit 132 also includes a coil 142 (which controls contactors C1 ) connected in parallel with the supply LED 140. When the coil 142 is energised, it closes the contactors 117a, 117b to allow electrical power to flow to the main switchboard 106. [44] The manual test circuit 116 also includes a first fuse 144 connected between the first conductor 100 and the sub-circuits and a second fuse 146 connected between the second conductor 102 and the sub-circuits. The two fuses provide overcurrent protection for the manual test circuit 116.

[45] With reference to Figures 1 through 3, the operation of the electrical testing device 1 will now be described. In Figure 1 , the electrical testing device 1 , in a deenergised state, receives no voltage. Usefully, an observer of the electrical testing device 1 can see that source LED 120 is off, indicating that there is no voltage across the first conductor 10 and the second conductor 102. In this state, pushing the push button 124 does not turn on the polarity test LED 126 and the SSR1 128 does not receive any voltage across its terminals. As the SSR1 128 is not energised, SSR1 switch 134 remains open or in the off condition. Similarly, as the SSR2 136 is not energised, the SSR2 switch 138 remains open.

[46] In Figure 2, a voltage (240VACRMS) is applied across the first conductor 100 connected to the active conductor 108 and the second conductor 102 connected to the neutral conductor 110 via the polarity switch 114, thereby having the correct polarity. In this state, the source LED 120 turns on indicating that there is voltage across the first conductor 10 and the second conductor 102.

[47] Pushing the push button 124 then closes the polarity test circuit 118 between the ‘active’ first conductor 100 and the earth conductor 104, the SSR1 128 is energised, and the polarity test LED 126 turns on but only while the push button 124 is pressed.

[48] Pushing the push button 124 causes the SSR1 switch 134 to close which in turn energises the SSR2 136 which causes SSR2 switch 138 to close. Closing the SSR2 switch 138 then keeps the SSR2 136 energised as long as a voltage is provided across the first conductor 100 and the second conductor 102, keeping the supply circuit 132 closed, and the supply LED 140 on, and the coil 142 energised.

[49] When the coil 142 is energised, it closes the contactors 117a, 117b to allow electricity to flow to the main switchboard 106.

[50] With reference to Figure 3, there is shown a portion of the electrical testing device 1 in an energised state with reversed polarity, i.e. the first conductor 100 is connected to the neutral line 110 of the supply, and the second conductor 102 is connected to the active line 108 of the supply. The source LED 38 turns on indicating that there is voltage across the first conductor 100 and the second conductor 102. However, as the second sub-circuit is connected across both the neutral conductor (i.e. first conductor 100) and the earth conductor 104, there is no voltage across the second sub-circuit. Thus, pushing the push button 122 has no effect on the polarity test LED 126. The SSR1 128 also remains de-energised and the SSR1 switch 134 remains open. As the SSR1 134 and the SSR2 136 are not energised, SSR2 switch 138 remains open, the supply LED 140 remains off and the coil 142 remains deenergised, thereby preventing the contactors 117a, 117n from closing and preventing electrical power from flowing to the main switchboard 106.

[51] In use, an observer of the electrical test device 1 will see that the source LED 130 is on, but the polarity test LED 126 and supply LED 140 do not turn on when the push button 122 is pressed, thereby indicating that the polarity of the connections is reversed.

[52] If the polarity is reversed, a user would change the polarity switch 114 to correct the polarity from the connection configuration shown in Figure 3 to the connection configuration shown in Figure 2, thereby connecting the first conductor 100 to the active line 108 and the second conductor 102 to the neutral line 110. The user can then press the push button 42 to check the polarity has been corrected.

[53] In Figure 4, there is shown an electrical testing device 2 according to a second embodiment of the present invention. The electrical testing device 2 is similar to the electrical testing device 1 described above but replaces the push button with a timer relay 224 to provide an automated testing device.

[54] Similar to the electrical testing device 1 , the electrical testing device 2 has a first conductor 100, a second conductor 102 and an earth conductor 104, all of which are connected to a main switchboard (MSB) 106. The electrical testing device 2 also includes an active conductor 108 and a neutral conductor 110. The earth conductor 104, active conductor 108 and neutral conductor 110 are all connected to a shore connection 112 which is in turn connected to a shore supply. There is also a polarity switch which is connected and operates the same as described above in relation to the electrical testing device 1 .

[55] Connected between the first conductor 100 and the second conductor 102 on a switchboard side, and the active conductor 108 and the neutral conductor 110 on a shore supply side, is a polarity switch 114.

[56] The polarity switch 114 controls a connection between the active conductor 108 and the neutral conductor 110 and the first conductor 100 and the second conductor 102 such that the electrical testing device 2 can be in one of two connection configurations: a first connection configuration and a second connection configuration, which will be explained in more detail below.

[57] In the first connection configuration (shown in Figure 5), the polarity switch 114 connects the active conductor 108 of the supply to the first conductor 100, and the neutral conductor 110 of the supply to the second conductor 102.

[58] In the second connection configuration (shown in Figure 6), the polarity switch 114 connects the neutral conductor 110 of the supply to the first conductor 100, and the active conductor 108 of the supply to the second conductor 102.

[59] The electrical testing device 2 also includes a double pole circuit breaker (CB1 ) having a first conductor CB and a second conductor CB.

[60] The first conductor CB is connected to the first conductor 100 between the main switchboard 106 and the polarity switch 114. The second conductor CB is connected to the second conductor 102 between the main switchboard 106 and the polarity switch 114.

[61] In addition to the double pole circuit breaker CB1 , the electrical testing device 2 includes a first contactor 117a and a second contactor 117b on the first conductor 100 and the second conductor 102, respectively. Both the first contactor 117a and the second contactor 117b are normally open.

[62] The first contactor 117a is connected to the first conductor 100 between the main switchboard 106 and the first conductor CB. The second contactor 117b is connected to the second conductor 102 between the main switchboard 106 and the second conductor CB.

[63] The electrical testing device 2 also includes an automatic test circuit 216 having a number of sub-circuits.

[64] A first sub-circuit for testing polarity takes the form of a polarity test circuit 222 connected between the first conductor 100 and the earth conductor 104. The polarity test circuit 222 includes a switch in the form of an electromechanical timer relay switch 224 (controlled by a timer relay 226) in the form of a single pole, double throw switch to open or close the polarity test circuit 222, a polarity indicator in the form of a polarity test LED 126 to indicate if the polarity test circuit is energised when the timer relay switch 224 is in the closed position, and a first relay in the form of a solid state relay (SSR1 ) 128. The timer relay switch 224, the polarity test LED 126 and the SSR1 128 are all connected in series with a resistor 130. [65] When the SSR1 128 is energised (through the closing of the timer relay switch 224, which will be described in more detail below), an SSR1 switch 134 becomes closed (shown in Figure 5). The polarity test circuit 222 is connected to the earth conductor 104 via the resistor 130. The resistor 130 is a 25kQ resistor.

[66] A second sub-circuit for testing the supply takes the form of a supply test circuit 232 connected between the first conductor 100 and the second conductor 102. The supply test circuit 232 includes the SSR1 switch 134 which is controlled by the SSR1 128, as described above. The supply test circuit 232 also includes a second relay in the form of a second solid state relay (SSR2) 136. When the SSR2 136 is energised it closes a SSR2 switch 138 (shown in an open condition) which is connected in parallel with the SSR1 switch 134.

[67] The supply test circuit 232 includes a supply indicator in the form of a supply LED 140 to indicate if the supply test circuit 232 is energised. The supply LED 140 is connected in parallel with the SSR2 136.

[68] The supply test circuit 232 also includes a coil 142 (which controls contactors 117a, 117b) connected in parallel with the supply LED 140. When the coil 142 is energised, it closes the contactors 117a, 117b to allow electrical power to flow to the main switchboard 106.

[69] A third sub-circuit for testing the source takes the form a source test circuit 218 having a source indicator in the form of a source light emitting diode (LED) 120 connected between the first conductor 100 and the second conductor 102. In use, the source LED 120 indicates if the source circuit 218 is energised or not.

[70] The automatic test circuit 216 also includes a first fuse 144 connected between the first conductor 100 and the sub-circuits and a second fuse 146 connected between the second conductor 102 and the sub-circuits. The two fuses provide overcurrent protection for the automated test circuit 216.

[71] As can be seen, the timer relay switch 224, the SSR1 switch 134 and the SSR2 switch 138 are electrically bridged by a first bridge bar 244 on the source side.

[72] The SSR1 switch 134 and the SSR2 switch 138 are also bridged by a second bridge bar 246 on the supply side.

[73] The timer relay 226 is also connected in series with a resistor 248 connected between the timer relay 226 and the second fuse 146.

[74] With reference to Figures 4 through 6, the operation of the electrical testing device 2 will now be described. [75] In Figure 4, the electrical testing device 2, in a de-energised state, receives no voltage. An observer of the electrical testing device 2 can see that source LED 120 is off, indicating that there is no voltage across the first conductor 100 and the second conductor 102. In this state, the timer relay switch 224 is open and does not turn on the polarity test LED 126 and the SSR1 128 remains open. As the SSR1 128 is not energised, the SSR1 switch 134 remains open. Similarly, as the SSR2 136 is not energised, the SSR2 switch 138 remains open.

[76] In Figure 5, a voltage (240VACRMS) is applied across the first conductor 100 (connected to the active conductor 108) and the second conductor 102 (connected to the neutral conductor 110) having the correct polarity. In this state, the timer relay 226 is energised causing the timer relay switch 224 to close, thereby completing the polarity test circuit 222 between the ‘active’ first conductor 100 and the earth conductor 104, and the source LED 120 is turned on indicating that there is voltage across the first conductor 100 and the second conductor 102.

[77] The use of the timer relay 226 allows the closing of the timer relay switch 224 to be controlled and create an automated test circuit. In some embodiments, the timer relay switch 224 can be delayed by an amount of time after the application of the voltage across the terminals of the timer relay 226. Alternatively, the opening of the timer relay switch 224 can be delayed by an amount of time once the application of the voltage across the terminals of the timer relay 226 ceases. In a preferred embodiment, the timer relay switch is programmed to remain on (i.e. closed) for between approximately 5 seconds and 10 seconds before returning to the off (i.e. open) position.

[78] The closing of the timer relay switch 224 allows voltage to be applied across the terminals of the SSR1 128 which closes the SSR1 switch 134. This, consequently, energises the SSR2 136 and closes the SSR2 switch 138. In addition, the coil 142 and the supply LED 140 (connected in parallel) are energised. Closing the SSR2 switch 138 keeps SSR2 136 energised (through the bridging on the supply side), keeping the SSR2 switch 138 closed, the supply LED 140 on, and the coil 142 energised.

[79] When the coil 142 is energised, it closes the contactors 117a, 117b to allow electricity to flow to the main switchboard 106.

[80] With reference to Figure 4, there is shown a portion of the electrical testing device 2 in an energised state with reversed polarity, i.e. the polarity switch 114 connects first conductor 100 to neutral conductor 110, and the second conductor 102 to the active conductor 108. The source LED 120 will turn on indicating that there is voltage across the first conductor 100 and the second conductor 102 and the timer relay switch 224 is closed as the timer relay 226 is also energised. However, as the polarity test circuit 222 is connected to both the first conductor 100 which is connected to the neutral conductor 110 and the earth conductor 104, there is no voltage across the polarity test circuit 22. Thus, the timer relay switch 224 being closed has no effect on the polarity test LED 126. The SSR1 128 also remains deenergised and the SSR1 switch 134 remains open. As the SSR1 128 and the SSR2 136 are not energised, SSR2 switch 138 remains open, the supply LED 140 remains off and the coil 142 remains de-energised, thereby preventing the contactors 117a, 117b from closing and preventing electrical power from flowing to the main switchboard 106.

[81] In use, similar to the electrical testing device 1 , an observer of the electrical test device 2 will see that the source LED 120 is on, but the polarity test LED 126 and the supply LED 140 do not turn on even though the timer relay switch 224 is closed, thereby indicating to the observer that the polarity of the connections is reversed.

[82] If the polarity is reversed, a user can change the polarity switch 114 to correct the polarity, thereby connecting the first conductor 100 to the active conductor 108 and the second conductor 102 to the neutral conductor 110. The SSR1 switch 134 and the SSR2 switch 138 would then close, activating the polarity test LED 126 and the supply LED 140 to indicate that the polarity is corrected and the system is correctly configured.

[83] In some embodiments, the manual test circuit 116 or the automated test circuit 216 can be mounted on a printed circuit board (PCB). An example of a PCB schematic 217 for the automated test circuit 216 can be seen in Figure 7.

[84] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term “comprises” and its variations, such as “comprising” and “comprised of” is used throughout in an inclusive sense and not to the exclusion of any additional features.

[85] It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. [86] The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.