—
19
—
which the instrument performs the loop test. This may result in the RCD not
tripping out. If the RCD still trips, temporarily replace it with a suitably rated
MCB for the duration of the test.
9
.
If the instrument measures greater than 20
Ω
the over-range symbol
“
OL
”
will be displayed. If this is the case, switch the instrument up a range to the
2000
Ω
range and repeat the test to obtain a satisfactory reading. If the
instrument is set to the "loop2000Ω"position,the test will be carried out at
the reduced current of 15mA flowing.This setting will be very unlikely to trip
out the circuit RCD.
Note
:
Do not connect phase to phase as this instrument is rated at 230V.
6.5
Loop impedance at 3 phase equipment
Use the same procedure as in 6.4 above ensuring that only one phase is
connected at a time i.e.
:
First Test: red prod to phase 1, black prod to neutral,
green crocodile clip to earth.
Second Test: red prod to phase 2, black prod to
neutral, green crocodile clip to earth etc.
#
WARNING
:
NEVER CONNECT THE INSTRUMENT TO
TWO PHASES AT THE SAME TIME.
Testing as described in 6.4 and 6.5 above will measure the Phase-Earth loop
impedance. If you wish to measure the Phase-Neutral loop impedance then
the same procedure should be followed except the earth clip should be
connected to the neutral of the system i.e.: the same point as the black neutral
probe.
If the system has no neutral then you must connect the black neutral probe to
the earth i.e.: the same point as the green earth clip. This will only work if there
is no RCD in this type of system.
Note
:
Before commencing the test, please clearly eliminate the load which
remains in the circuit to be tested, otherwise it may affect the accuracy
of the measurement.
When the mains voltage is lower than 100V, the "low voltage" indication
"Lo" is displayed in the LCD display. Also, when the mains voltage is
higher than 260V, the "high voltage" indication "Hi" is displayed in the
LCD display.In either case, testing cannot be carried out as the test
button does not function even if you press it .
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sales@calcert.com
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