Model 3731 Clamp-On Ground Resistance Tester
Catalog# 2117.61
The Clamp-on Ground Resistance Tester Model 3731 measures
ground rod and small grid resistance through any season, without the use of auxiliary
ground rods.
Clamp-on Ground Resistance Testers are used in multi-grounded systems without
disconnecting the ground under test. The Model 3731 simply clamps around the ground
conductor or rod and measures the resistance to ground. By performing measurements on
intact ground systems, the user also verifies the quality of the grounding connections and
bonds. Resistance and continuity of grounding loops around pads and buildings may also be
measured.
The Model 3731 also provides alarm and memory functions.
Features
Simple and fast clamp-on operation - no leads, no
auxiliary rods or spacing requirements. No need to disconnect neutral service
Direct reading of ground resistance from
0.01Ω to 1200Ω
Direct reading of continuity and ground loop
resistance
Direct reading of ground leakage current from 1mA to
30Arms
Jaw design with large 1.25" (32mm) window
Auto-off for power management
Alarm function with adjustable setpoint and buzzer
Memory function to store 99 field measurements for
later retrieval and analysis
Patented design
Applications
Measure ground rod and small grid resistance
Use in multi-grounded systems without disconnecting
the ground under test
Measure resistance and continuity of grounding loops
around pads and buildings
Measure leakage current flowing to ground or
circulating in ground loops
Conduct quick field checks
Conduct field surveys and retrieve and analyze
readings are a later time
Electrical
Specifications
Measurement Range
Type
Current
Measurement Ranges
Ground
Resistance Ranges
Range
Auto-Ranging
1mA to 30.00Arms
Auto-Ranging
0.01 to 1200Ω
Measurement
Range
1
to 299mA
0.300A
to 2.999A
3.00A
to 29.99A
0.10
to 1.00Ω
1.0
to 50.0Ω
50.0
to 100.0Ω
Resolution
1mA
0.001A
0.01A
0.01Ω
0.1Ω
0.5Ω
Accuracy
±2.5%
of Reading ± 2mA
±2.5%
of Reading ± 20mA
±2%
of Reading ± 0.02Ω
±1.5%
of Reading ± 0.1Ω
±2.0%
of Reading ± 0.5Ω
Type
Ground
Resistance Ranges
Range
Auto-Ranging
0.01 to 1200Ω
Measurement
Range
100
to 200Ω
200
to 400Ω
400
to 600Ω
600
to 1200Ω
Resolution
1Ω
5Ω
10Ω
50Ω
Accuracy
±3.0%
of Reading ± 1Ω
±6%
of Reading ± 5Ω
±10%
of Reading ± 10Ω
Approx.
25% of Reading ± 50W
Resistance
Measurement Frequency:
2403kHz
Resistance
Overload:
OL
displayed above 1200Ω
Current
Measurement Frequency:
47
to 800Hz
Current
Overload:
OL
displayed above 30Arms
Power
Source:
9V
Alkaline battery
Battery
Life:
Typical:
8 hours or approx. 1000 measurements of 30 seconds
Mechanical Specifications
Display:
3-3/4 Digit, 1.73" x 1.10" (44 x 28mm)
Operating Temperature:
14 to 131°F (-10° to 55°C)
Storage Temperature:
40 to 158°F (-40°C to 70°C)
Relative Humidity:
0 to 90% RH @ 14 to 104°F (-10°C to 40°C), 75%
RH @ 131°F (55°C)
Dimensions:
9.25 x 3.94 x 2.17 (235 x 100 x 55mm)
Weight:
2.2lbs. (1kg)
Jaw Window Diameter:
1.25" (32mm)
Jaw Opening:
1.38" (35m)
Case:
Lexan 920A (UL94V)
Colors:
Gray body, red jaws
Shock Test:
IEC 68-2-27
Vibration Test:
IEC 68-2-6
Drop Test:
(1m); IEC 68-2-32
Dielectric Test:
2500VAC
Environmental:
IP30, IEC 359 Group III
Working Voltage:
150V Cat. III - Pollution Degree 2 300V, Cat. II -
Pollution Degree 1
