Operation Manual

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Step 3 Followtheconnectiondiagramshowningure5.15(seethechapterContact voltage)
to perform trip-out time measurement.
Step 4 Check the displayed warnings and online voltage/terminal monitor before starting the
measurement. If OK, press the TEST key. After performing, the measurement results
with PASS/FAIL indication appear on the display.
Fig. 5.18: Example of trip-out time measurement results
Displayed results:
t: Trip-out time
Uc: Contact voltage
Save displayed results for documentation purposes. Refer to chapter 6.1 for further information on
setting functions and saving of measurement results. (BENNING IT 120 B only)
Note:
- Parameters set in this function are also kept for other RCD functions.
- RCD trip-out time measurement will be performed only if contact voltage at nominal differential
current is lower than the set limit contact voltage.
- The measurement of contact voltage in pre-test does not normally trip an RCD. However, the
triplimitmaybeexceededasaresultofleakagecurrentowingtothePEprotectiveconductor
or via a capacitive connection between L and PE conductors.
5.3.8 Trip-out current (RCD )
An ever increasing fault current serves to test the limiting sensitivity for the FI/RCD tripping. The
device increases the testing current in small steps over the whole range as follows:
RCD type
Increasing fault current
Wave form
Initial value Final value
AC 0.2×I
∆N
1.1×I
∆N
Sine AC
A, F (I
∆N
≥30mA) 0.2×I
∆N
1.5×I
∆N
Pulsating
A, F (I
∆N
= 10 mA) 0.2×I
∆N
2.2×I
∆N
B, B+ 0.2×I
∆N
2.2×I
∆N
Direct current DC
ThemaximumtestingcurrentisID(trippingcurrent)orequalsthenalvalue,iftheFI/RCDhasnot
tripped.
How to perform trip-out current measurement:
Step 1 Select FI/ RCD TEST (RCD) with the function selector switch. Use the keys / to se-
lect Trip-out current (RCD). The following menu is displayed:
Fig. 5.19: Trip-out current measurement menu
Connect the test cable to the BENNING IT 110/ BENNING IT 120 B.