During repeat testing in accordance with EN 50699 or EN 50678 (formerly VDE 0701/0702), error messages may be generated by the device tester used. These are often cable reels with a standby indicator or power strips with illuminated switches.
Important to know: These glow lamps or LEDs represent an electrical connection (load) between L and N with a certain resistance.
If the device tester is equipped with an automated test sequence for extension cords and this test sequence is used on products with a standby indicator or illuminated switches, this can lead to misinterpretation of the measurements and thus error messages. This is the case, for example, when an insulation measurement is performed not only between L/N and PE, but also between L and N. Or when a continuity test of L and N using a measuring loop at the output reacts unexpectedly to the lamp/LED.
Our recommendation for such cases: Do not perform the tests on such devices with a standby indicator or illuminated switch using an automated test sequence for extension cords, but select the appropriate tests according to EN 50699 or EN 50678 manually one after the other, taking into account the lamp/LED as an electrical connection (load) between L and N.