VOLTCRAFT VC40 Operating Instructions Manual page 38

Disconnect all devices/turn off all lights that are con-
nected to the fuse if the test indicates a voltage drop
between the earth and neutral wires. This may indi-
cate a broken cable.
Fault current test (RCD – residual current device)
Carry out a fault current test to check that the mains socket is
earthed correctly. In the event of a fault, the fault current must
be discharged via the earth wire until the fuse is triggered. The
test delivers a 30 mA current through the earth wire and checks
whether the residual current circuit breaker breaks the circuit
within 0.3 s (300 ms – maximum safe trip time).
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