VR2250
Page 43 of 131
6.4.5. Measurement procedure and results of " R
A
" mode
1. Select
R
A
mode by means of the
F1
key.
2. Connect the Red, Green and Black connectors of the three-terminal mains cable or
of the split cables to the corresponding input terminals of the instrument
B1
,
B3
,
B4
.
P
B2
B3
B4
B1
I1
Instrument connection for P-PE test in a 230V
single-phase System
B2
B3
B4
B1
I1
1
3
N
Instrument connection for P-PE in a 400V three-
phase system
3. Connect the mains plug into a 230V 50Hz socket or the crocodiles to the
conductors of the three-phase system (see previous pictures).
4. If possible disconnect all low impedance loads downstream of the point at which
the measurement is to be taken; as such impedance would be in parallel with
the line impedance to be measured.
5. The key
F4
permits to select one of the following
limit values for the contact
voltage
(which can be shown cyclically when pressing the key):
50V
(default)
25V.
6. Press the
START
key
once
to execute a test with “
0°
” test current.
or
Press the
START
key
twice
to execute a test with “
180°
” test current.
CAUTION
The
R
A
measurement make a test current of 15mA. This may cause the
tripping of 10mA. If necessary perform the test upstream of the switch. Never
disconnect the test leads when the message
"MEASURING"
is displayed.
At the end of the test
the instrument emits a
double sound signal
indicating that the test
is correctly
terminated
and
displays the values
alongside.
LOOP
05.06.01
Value of phase to Earth
Resistance expressed in
Ω
.
2
Ω
115A
Freq=50.0HZ
VP-N=231V Vp-PE=231V
R
A
Effective value of the phase
to Earth prospective short
circuit current expressed in
Amps calculated according to
the following formula.
Working mode
FUNC
Formula for calculation of prospective short circuit current:
PE
N
CC
Z
U
I
=
Where U
N
= Nominal phase to neutral voltage =
127 if V
meas
≤
150
230 if 150V< V
meas
≤
250
This result can be stored pressing the
SAVE
key
twice
(according to paragraph 9.1).
START
STOP
I
I
Red
Green
Black
Red
Black
Green
