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26.06.2015

Selftest: Automated function tests offer increased safety

Doepke's intelligent residual current circuit-breakers are self-monitoring


Norden, 16/03/2015. Doepke's new 'Selftest' series of intelligent residual current circuit-breakers perform a self-test at regular intervals. Whereas previously self-tests had to be activated manually by pressing the test button, these devices now do this automatically every 30 days. What's more there is a check to ensure that the switch is functioning properly. Bypass contacts provide the power supply to the system during these self-tests, and a programmable potential-free contact allows a log to be kept.

The 'Selftest Restart' complements this function by automatically restarting in the event of faulty tripping. Instances of faulty tripping may be caused by lightning strikes, transient leakage currents, vibrations or a reduction in the insulation resistance caused by moisture or dirt. After testing the insulation resistance against earth, the Selftest Restart switches the power supply back on within ten seconds. If the device detects a fault, it performs another test after two minutes. While there is still a fault, the test will be repeated every two minutes and there will be no attempt to restart the system until there are no faults present.

These functions provide increased safety as there is no longer any need to press the test button to manually test the protective function, meaning there is no risk of someone forgetting to do it. System availability is also increased if the power supply can be switched back on quickly by the Selftest Restart, meaning losses incurred due to downtimes are also reduced.

Both devices are available in two and four-pole designs. Mounting and connection are both easy and intuitive.