Improvements relating to the testing of an earth connection
First Claim
1. A device for testing an earth connection that is isolated from a mains electricity supply, the device comprising means for electrically connecting the device to the earth connection, means for electrically connecting the device to an electrically conductive item having a capacitance relative to an adjacent surface of the earth that is within a pre-determined range of capacitances, means for generating an AC signal and delivering the AC signal to the electrically conductive item, frequency determination means for determining whether a frequency of the generated AC signal falls within a predetermined range of frequencies, and means for determining whether a resistance between the earth connection and an earth reference potential is less than a maximum earth resistance value from an output of said frequency determination means.
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Accused Products
Abstract
A device (10) is disclosed that is suitable for testing an earth connection (30) that is isolated from a mains electricity supply. The device (10) comprises means (14, 40) for electrically connecting the device (10) to the earth connection (30), and means (16, 32) for electrically connecting the device (10) to an electrically conductive item (20) having a capacitance relative to an adjacent surface of the earth that is within a pre-determined range of capacitances. Furthermore, the device (10) includes means for generating an AC signal and delivering the AC signal to the electrically conductive item, and means for determining whether the resistance between the earth connection (30) and earth reference potential is less than a maximum earth resistance value. This determination is achieved by comparing the frequency of the generated AC signal with a pre-determined range of frequencies.
20 Citations
27 Claims
- 1. A device for testing an earth connection that is isolated from a mains electricity supply, the device comprising means for electrically connecting the device to the earth connection, means for electrically connecting the device to an electrically conductive item having a capacitance relative to an adjacent surface of the earth that is within a pre-determined range of capacitances, means for generating an AC signal and delivering the AC signal to the electrically conductive item, frequency determination means for determining whether a frequency of the generated AC signal falls within a predetermined range of frequencies, and means for determining whether a resistance between the earth connection and an earth reference potential is less than a maximum earth resistance value from an output of said frequency determination means.
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26. A method of testing an earth connection that is isolated from a mains electricity supply, the method comprising the steps of:
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(a) electrically connecting a device to the earth connection, and electrically connecting the device to an electrically conductive item having a capacitance relative to an adjacent surface of the earth that is within a pre-determined range of capacitances, (b) generating an AC signal and delivering the AC signal to the electrically conductive item, (c) determining whether a frequency of the generated AC signal falls within a predetermined range of frequencies, and (d) determining whether the resistance between the earth connection and earth reference potential is less than a maximum earth resistance value based on the determination whether the frequency of the generated signal falls within the predetermined range of frequencies. - View Dependent Claims (27)
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Specification