Ground Resistance Testers Models 6422 & 6424
37
3.3.2 Resistance Measurement (2P)
Quantities of
influence
Limits of the
range of use
Variation of the measurement
Typical
Maximum
Temperature
(14 to 122°) F
(-10 to 50) °C
± (25 ppm R +
10 mΩ/°C)
± (200 ppm R +
2 mΩ/°C)
Relative humidity (10 to 90) % RH
± 1 % R
± 2 % R
Supply voltage
Model 6422:
(6.0 to 9.6) V
Model 6424:
(6.0 to 7.6) V
-
± (2 % R + 1 Ω)
50/60 Hz voltage
superimposed on
the test voltage
(0 to 3) V
(3 to 25) V
± (0.5 % R + 0.5 Ω)
± (2 % R + 5 Ω)
± (2 % R + 1 Ω)
± (4% R + 10 Ω)
3.3.3 Resistance Measurement (3P)
Quantities of
influence
Limits of the
range of use
Variation of the measurement
Typical
Maximum
Temperature
(14 to 122) °F
(-10 to 50) °C)
± 1 % R
± 2 % R
Relative
humidity
(10 to 90) % RH
-
± 2 % R
Supply voltage
Model 6422:
(6.0 to 9.6) V
Model 6424:
(6.0 to 7.6) V
-
± (2 % R + 1 Ω)
Voltage in series
between S and
E, 50/60 Hz
(0 to 3) V
± (0.5 % R + 0.2 Ω) ± (1 % R + 1 Ω)
(3 to 25) V
± (2 % R + 8 Ω)
± (4 % R + 20 Ω)
Voltage in series
between H and
E, 50/60 Hz
(0 to 3) V
± (0.5 % R + 0.2 Ω) ± (1 % R + 1 Ω)
(3 to 25) V
± (20 % R + 10 Ω) ± (30 % R + 20 Ω)
Rod resistance
R
S
(0 to 50) kΩ
-
± (2 % R + 1 Ω)
Rod resistance
R
H
R
H
< 100 x R
E
and R
H
< 50 kΩ
± (2 % R + 2 ct)
± (10 % R + 5 ct)
