METREL MI 3125 - Trip-out Time (RCDt) Measurement

MI 3125 EurotestCOMBO Testing RCD
34
RCD type
Contact voltage Uc
proportional to
Rated I
ΔN
AC G
1.05×I
ΔN
AC
S
2×1.05×I
ΔN
any
A G
1.4×1.05×I
ΔN
A
S
2×1.4×1.05×I
ΔN
≥ 30 mA
A G
2×1.05×I
ΔN
A
S
2×2×1.05×I
ΔN
< 30 mA
Both models
Table 5.1: Relationship between Uc and I
Δ N
Loop resistance is indicative and calculated from Uc result (without additional
proportional factors) according to:
N
C
L
I
U
R
Δ
= .
UK version
Figure 5.19: Example of contact voltage measurement results
Displayed results:
Uc........Contact voltage.
Rl.........Fault loop resistance.
5.5.2 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 switch.
 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 5.18).
 Press the TEST key to perform the measurement.
Figure 5.20: Example of trip-out time measurement results