Ideal 61920 Manuel D’Utilisation

Page 14

A/Ω

• Follow the procedure described in "7-1 Normal measurement of current" and measure the 

current flowing on the earthed wire prior to the measurement of earth resistance.
If "             " is displayed in the upper right of the LCD, it means there is too much interference to 
obtain an accurate reading. To avoid such inaccuracies, reduce the current flowing on the ground 
wire by turning off the device causing this current to flow.  

• Measurements cannot be made for multi-ground systems or when the ground resistance under 

test is smaller than the other ground resistances. 

• If the jaws of the instrument are not properly closed, the "        " mark will be displayed. Close the 

transformer jaws properly to continue with the measurement.

• The response time is about 7 seconds on the earth resistance function. Note the reading after it 

becomes stable.

• Measurement procedure

* Press the Function button               and select the Earth resistance function.
*  Confirm that the displayed unit of measure is " Ω " and " MEM " is not displayed in the upper 

left corner of the LCD.

* Press the lever to open the transformer jaws and close them around the ground wire under test.
*  The measured resistance value is displayed on the LCD.

<Noise check function>

When in the earth resistance function, the "             " symbol is displayed on the LCD. Under the 
following scenarios, noise can affect the measurement accuracy:
1 The current flowing on the ground wire is exceeding the following values:

2 The current flowing on the ground wire includes a harmonic waveform.

<Jaws check function>

The "         " symbol is displayed when the transformer jaws of the instrument are not properly 
closed.  Measurement is stopped while this symbol is displayed on the LCD.

Range of Earth Resistance Function

Allowable current value

20Ω

2A or less

200Ω / 1200Ω

400mA or less

ND 5417-1 61-920 Ins  9/26/06  8:49 AM  Page 14