Earth 3W - Three Wire Earth Resistance Measurement - Amprobe GP-2A Manual De Uso

4.3 EARTH 3W – Three Wire Earth Resistance Measurement
The measurement is carried out in compliance with standards IEC 781, VDE 0413, EN61557-5.
�CAUTION
• The instrument can be used for voltage and current measurements on installations with
over voltage category CAT III 240V to earth and maximum voltage of 415V between inputs.
Do not connect the instrument to installations whose voltages exceed the limits indicated
in this manual. Exceeding such limits may cause electric shock to the user and damage the
instrument
• Always connect the cables to the instrument and to the alligator clips when the latter are
not connected to the plant under test
• Always respect the Hand-held area of probe (see 4.2)
• If the length of the supplied cables isn't suitable for the plant under test (see Par. 11), You
can create your own extensions following indications in Par. 11.2.1
1. Turn on the instrument pressing the ON/OFF key
2. Pressing right/left arrow keys , select MOD, then pressing up/down arrow
keys , select 3W option
3. A screen similar to the one below appears where the input interfering voltage value of
the instrument is displayed
4. Connect the blue, red, green and black cables to the corresponding instrument's input
terminals H, S, ES, E then adding crocodiles if necessary
5. Extend, if necessary, the blue and red measuring cables separately using cables with
proper section. Adding any extension does not require calibration and does not affect
the measured earth resistance value
6. Drive the auxiliary rods into the ground keeping to the distance instructions provided by
the standards (§ 11.2)
7. Connect crocodiles to the auxiliary rods and to the installation under test (see Fig. 2)
Fig. 2: Three-wire earth resistance measurement
(Input interfering voltage value)
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