Benning IT 120 B 044102 Manual De Usuario
Los códigos de productos
044102
39
- Loop impedance (Zs) measurement trips an RCD.
5.4.2 Loop impedance (Zs
rcd
)
Zs
rcd
sub-function performs measurements in supply systems equipped with an RCD. The measu-
rement current is small enough to prevent the RCD from tripping.
Modern measurement methods allow for stable and reliable results despite low measured signals.
Modern measurement methods allow for stable and reliable results despite low measured signals.
The prospective fault current is calculated on the basis of measured resistance as follows:
P PE
L
n
PFC
R
scaling factor
U
I
-
x
=
where
U
n
Voltage range
115 V
100 V
≤ U
L-PE
< 160 V
230 V
160 V
≤ U
L-PE
≤ 264 V
Because of different definitions of the prospective fault current I
PFC
in different countries, the user
can set the scaling factor in the Setup menu (see chapter 4.4.2).
How to perform the loop impedance measurement:
Step 1
Step 1
Select Zs/Ik (L-PE) (loop impedance) with the function selector switch. Use the
/
keys to select the Zs
rcd
sub-function. The following menu is displayed:
Fig. 5.31: Loop impedance measurement menu
Connect the test cable to the BENNING IT 110/ BENNING IT 120 B.
Step 2
Set the following measuring parameters:
-
Fuse type
-
Fuse current rating
-
Fuse trip-out time
Appendix A contains a list of different fuse types.
Step 3
Follow the connection diagram shown in figure 5.29 to perform loop impedance measu-
rement. Use the Help function if necessary.
rement. Use the Help function if necessary.
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
appear on the display together with the PASS/FAIL indication (if applicable).
measurement. If OK, press the TEST key. After performing, the measurement results
appear on the display together with the PASS/FAIL indication (if applicable).
Fig. 5.32: Example of loop impedance measurement results