DetailsMaxim

AEMC 4500 20kohm 4 Point Ground Resistance Tester

The Digital Ground Resistance Tester Model 4500 is designed for measuring very low resistance on large grounding systems, such as ground grids and ground mats. It rejects high levels of interference voltages at DC or 60Hz and its harmonics, and can be used under difficult conditions such as high stray currents or excessive auxiliary electrode resistance without substantially affecting accuracy.

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Feature Specification

Measures soil resistivity (4-Point)
Measure ground resistance (2- and 3-Point) Fall-of-Potential Method
Step voltage tests and touch potential measurements
Selectable: three test currents and five resistance ranges
Measures very low resistance on large grounding systems and grids
High test current also enables geological surveys
Large easy-to-read LCD
Display includes indicators for excess stray current and voltage, high auxiliary rod resistance and fault connection
Battery (rechargeable) powered or external 12VDC
Rugged dustproof and rainproof field case
Can be used for continuity tests on bonding
Includes power cord, 12V NiCD battery, hex key, spare fuse and user manual

AEMC 4500 Applications

Three-point measurement of large grounding grids, counterpoises, ground mats and grounded equipment.
Soil resistivity tests (4-Point measurement), commonly performed by utilities at proposed construction sites. Using soil resistivity analysis, the size and complexity of grounding system construction can be evaluated.
The Ground Resistance Tester Model 4500 will measure the resistivity of epoxies, cement, ground enhancement materials and many other substances.
Step or touch potential levels under true fault conditions can be deter- mined by using the Model 4500 to inject a simulated low-level fault into an electrical system. When used in this fashion, the Model 4500 will display readings in volts per fault ampere.
Two-point tests for continuity tests on bonding or on pre-established grounds.

ELECTRICAL
Ranges	2Ω	20Ω	200Ω	2000Ω	20kΩ
Resolution	1mΩ	10mΩ	0.1Ω	1Ω	10Ω
Resistance Measurement Frequency	128Hz square wave
Test Current	2mA, 10mA, 50mA
Accuracy	±2% of Reading ± 1ct from 10% to 100% of range
Auxiliary Electrode Resistance	Ry: 50kΩ on 20Ω, 200Ω, 2000Ω & 20kΩ ranges; 5kΩ on 2Ω range Rz: 2mA range: 15kΩ; 10mA range: 3000Ω; 50mA range: 400Ω
Interference	The unit is designed to reject high levels of interference voltages at DC, or 50/60 Hz and their harmonics
Noise Influence on Accuracy	0.5% of range (max) to 20V peak
Power Source	Built-in rechargeable 12V, one Ah NiCD battery, or external 12 VDC; low battery indication. Battery can be recharged with built-in dual voltage charging unit: 94 to 127V or 187 to 253V (47 to 450Hz)
Charging Time	14 hours typical
Charging Supply Voltage	Internally selectable 110/220V, 45 to 450Hz
Battery Life	Four hrs on 50mA test current (800 15 sec measurements), Seven hrs on 2mA and 10mA test currents (1500 15 sec. measurements)
Fuse Protection	500Vrms measurement circuit
MECHANICAL
Display	7-segment LCD, 0.71"" (18mm) high (31/2 digit); 2000-count
Connection	Terminals accept spade lugs with min. gap of 6mm or standard 4mm banana jacks
Operating Temperature	14° to 122°F (-10° to 50°C)
Dimensions	15.75 x 10.2 x 9.8"" (400 x 260 x 250mm)
Weight	14 lbs (6.5kg) approximate
Case	Heavy-duty plastic, with detachable cover and carrying handle
Colors	Case: safety yellow; Front panel: brown
Dielectric Test	2000Vrms, 50/60Hz between 4 interconnected measuring terminals and any external metal ground; 2000Vrms, 50/60Hz between line input and measuring terminals on front panel
Environmental	O-ring sealed faceplate against water and dust; sealed cover when closed; IEC529, DIN 0470-T1
SAFETY
Rating	EN 61010
Double Insulation	Yes
Impact Resistance	Shock and vibration according to MIL-T-28800D class 3
CE Mark	Yes