MI 3108 EurotestPV
Measurements
– a.c. LV installations
54
Displayed results:
Uc ........ Contact voltage.
Rl ......... Fault loop resistance.
Rmax ... Maximum earth fault loop resistance value according to BS 7671
5.6.2 Trip-out time (RCDt)
Trip-out time measurement verifies the sensitivity of the RCD at different residual
currents.
Trip-out time measurement procedure
Select the
RCD
function using the function selector keys.
Set sub-function
RCDt.
Set test
parameters
(if necessary).
Connect
test cable to the instrument.
Connect
test leads to the item to be tested (see
figure 5.21
).
Press the
TEST
key to perform the measurement.
Store
the result by pressing the MEM key (optional).
Figure 5.24: Example of trip-out time measurement results
Displayed results:
t ........... Trip-out time,
Uc ........ Contact voltage for rated I
N
.
5.6.3 Trip-out current (RCD I)
A continuously rising residual current is intended for testing the threshold sensitivity for
RCD trip-out. The instrument increases the test current in small steps through appropriate
range as follows:
RCD type
Slope range
Waveform
Start value End value
AC
0.2
I
N
1.1
I
N
Sine
A, F (I
N
30 mA)
0.2
I
N
1.5
I
N
Pulsed
A, F (I
N
= 10 mA)
0.2
I
N
2.2
I
N
B, B+
0.2
I
N
2.2
I
N
DC
Maximum test current is I
(trip-
out current) or end value in case the RCD didn’t trip-out.
