| 摘要 |
<p>A device for detecting the presence or absence of a potential difference across two conductive elements, including means to provide an indication of a potential difference between said two conductive elements, the means having a test connection between the two elements comprising two spaced conductive lines in parallel, each line having self testing means including detecting means connected across said two lines and means to apply a test voltage through said two lines to test the integrity of the lines and their connection to the conductive elements with indicator means to provide an alarm signal should the detector indicate an abnormal response in said test voltage indicative of a fault in the line connections and/or one or other of the lines.</p> |
