Structure of a DC (type B) sensitiv RCD

A Trigger
M Mechanism of RCD
E Tripping electronic for DC fault current
T Test circuit
n Secondary winding
W1 Current transformer for AC fault current
W2 Current transformer for DC fault current
Selecting the Trip Current
For the UNITEST instruments TELARIS RCD as well as UNITEST Schuko-Fix, the trip current of the RCD safety switch is set via a rotary switch. Upon pressing the button, a fault current is fed into the system or the current circuit for the duration of <300 ms.
After a maximum time period of 300 ms the RCD switch must trip. Conventional values are between 15 ms and 50 ms. The UNITEST TELARIS RCD indicates on the display, whether the RCD switch is in working order or whether it has to be replaced by a specialist. This test using UNITEST TELARIS RCD must, for example,
supply cabinets. The display in “clear text“on the UNITEST Telaris RCD also allows staff having been trained on the job to carry

out the tests. Possible application areas are, testing RCD safety switches by masons in work site general supply cabinets, caretakers for housing companies, etc.
Socket Test
UNITEST RCD Testers are equipped with a display to check correct wiring and to provide ground error indication on three wire socket systems.
Hereby, the contact voltage is monitored for all UNITEST RCD testers and possible PE errors are clearly indicated.
Mobile RCD Safety Switch
The RCD extension is appropriate as protection against electrical accident. For all applications requiring portable personal protection, the RCD extension can be connected to the current circuit. The RCD switches off, within 300 ms after fault current occurrence at the latest. Practical application of the RCD safety switch are for lawn mowers, drilling machines, extension leads, etc.