Hioki FT6031-50, Instruction Manual

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38
Precise Measurement for Earth Resistance
(Precise Measurement Method, 3-pole Method)
3.4 Precise Measurement for Earth
Resistance
(Precise Measurement Method,
3-pole Method)
WARNING
The instrument can output a voltage of approx. 30 V.
Although the instrument has a dustproof, jet-proof
and waterproof structure, the instrument should
always be dried before using it for measurement so as
to avoid electric shock.
CAUTION
Do not connect the measurement cables if any foreign
material remains inside the measurement terminals. It may
cause failure.
There are two types of measurement method for earth resistance:
precision measurement method (3-pole method) and simplified
measurement method (2-pole method), and the precision
measurement method (3-pole method) is the basic measurement
method for earth resistance.
The simplified measurement method is used when measurement
cannot be performed by the precision measurement method. The
precision measurement is performed by inserting two auxiliary
earthing rods into the ground as shown in the figure on p. 42.
Measurement of large-scale earthing electrodes
When measuring a large-scale earthing electrode such as a mesh
earthing electrode, ring earthing electrode, or earthing electrode
provided by a large building structure, it cannot be accurately
measured since the H(C) electrode and S(P) electrode come inside
HIOKI FT6031B961-00