Cable testing device and method

The invention relates to a cable testing device (6) integrated into a high-voltage electrical apparatus (3) equipped with a main circuit (17) comprising: at least a line connection (4) and a cable output (5); and at least one operating means including at least one switch (1a) and/or one isolator (1b, 1c, 1d). The testing device (6) is characterised in that it is installed as a first element upstream of the cable output (5) and simultaneously downstream of the switch (1a) and/or the isolator (1b)(1c)(1d), the testing device (6) being independent of the operation of the main circuit (17), such that the contacts of the switch (1a) and/or the isolator (1b)(1c)(1d) are maintained in the open position during cable testing, with voltage being injected for the testing of cables at the cable output (5) using the testing device (6).