GAOTek Earth Resistance Tester with 2, 3 and 4-Pole Measurement Testing

Additional Information

Product Description

1. LCD
2. Button area
3. Rotary switch for selecting function
4. RS232 interface
5. Interface of testing wires
6. P(S) interface: Voltage electrode
7. C(H) interface: Current electrode
8. E interface: Earth electrode
9. ES interface: Auxiliary earth electrode
10. Standard test wires
11. Auxiliary earthing rods
12. Simple test wires

LCD Display

1. Progress bar (Dynamic display the progress of testing)
2. Alarm symbol (Display when open alarm function, flash when exceed the alarm value)
3. Exceed voltage symbol (Display when the measured voltage exceed 30 V, please pay attention to the safety)
4. AC symbol
5. Data hold symbol (Display when press MEM to hold data)
6. Data access symbol (Display when long press MEM for at least 3 seconds to access data)
7. Data storage symbol (Display when press MEM to hold data and store)
8. Interference signal symbol (Display when the interference voltage exceeds 5V)
9. Low battery symbol (Display when the battery voltage decreases to 7.5 V)
10. Display the group number of stored data, and display countdown.
11. Interference electrode symbol (Display when the electrode exceeds 5 V interference voltage)
12. Measured data
13. Voltage unit symbol
14. Resistance, soil resistivity, length unit symbol (Ω, kΩ, Ωm, kΩm, m)

Operation Methods

Switch On/Off

Rotate FUNCTION rotary switch to fulfill switch on and off. When rotary switch button displays

“OFF” for shut-off. The Tester has no auto shut-off function, so please shut it off after usage in case of battery consumption saving.

Battery Voltage Check

After switch on, if LCD displays low battery voltage icon “” which indicates that battery voltage is low, and please replace the battery in compliance with instructions. Adequate battery power can ensure the accuracy of measurement.

AC Voltage Measurement

AC voltage measurement refers to the general commercial AC voltage measurement, pay attention to the difference between earthing voltage, the meter can be used for testing below 600V AC line voltage.

As shown below: Firstly, connect test wires with P(S), ES interface, secondly connect test wires with tested line, then rotate FUNCTION rotary switch to “EARTH VOLTAGE” and start testing, LCD will display the test results.

Earth Voltage Measurement

Earth voltage: That is a potential differences between zero potential differences and earthing equipment shell, earthing wires, earthing body when electrical equipment has a earthing fault. Earth voltage is the potential differences between the earth. As a reference point, the earth is zero potential.

Earth voltage measurement need to use one auxiliary earthing rod. Please pay attention to the difference from commercial AC voltage measurement. As shown below: meter, auxiliary earthing rods, testing wires are all connected, rotate FUNCTION rotary switch to “EARTH VOLTAGE” and start testing, LCD will display the test results.

4-wires Precise Earth Resistance Measurement

4-wires measurement: The 4-wires method can eliminate influence of contact resistance (usually result from dirty or rusty) between measured earthing body, auxiliary earthing rods, test clips, meter’s input interface. The 4-wires method can also eliminate influence of line resistance. So it is better than 3-wires measurement.

As shown below: Start from the measured body, interval 5m-20m, respectively insert P(S), C(H) auxiliary earthing rods deep into the earth in a straight line, and then connect testing wires (black, green, yellow, red) from E, ES, P(S), C(H) interfaces corresponding to measured earth electrode E, auxiliary voltage electrode P(S), auxiliary current electrode C(H).

3-Wires Earth Resistance Measurement

3-wires measurement: As shown below, short-circuit ES and S interface, which is 3-wires measurement. The operation of meter is the same with 4-wires measurement. The 3-wires method can’t eliminate influence of line resistance, also can’t eliminate influence of contact resistance between meter and testing wires, testing wires and auxiliary earthing rods. Meanwhile, oxidation layer on measured earthing body must be removed when measuring.

2-Wires Simple Measurement

2-wires method: This method is a simple method for measurement that does not use auxiliary earthing rod, taking the earth electrode with the minimal existing earth ground resistance value as auxiliary earth electrode, and connecting by two simple testing wires (in which C(H)–P(S), E–ES interfaces are in short circuit). It can make use of metal pipes, fire hydrants and other metal buried objects, common earthing of commercial electric power system or lightning protection earth ground electrode and others to replace auxiliary earthing rods C(H),P(S), and pay attention to remove oxide layer on the connection point of the selected metal auxiliary earthing object when making measurement.

Wire connection is as following figure, and refer to 4-wires measurement for other operations.

2-wires simple method for measurement of earth ground resistance, its reading on tester is the total value of earth ground resistance value of measured earthing object and that of commercial earthing object, that is:

R=RX＋re

In which:

R is the tester reading value;

RX is the earth ground resistance value of measured earthing object; re is the earth ground resistance value of common earthing object like commercial use power system.

Then, the earth ground resistance value of measured earthing object

is: RX=R－re

Soil Resistivity Measurement

Soil resistivity is measured by 4-pole method (Wenner method)

4-pole method (Wenner method): Connect testing wires as shown below, pay attention to the distance between auxiliary earthing rods, and the embedding depth. Respectively insert C(H), P(S), ES, E auxiliary earthing rods deep into the earth in a straight line, and then connect testing wires (red, yellow, green, black) corresponding to C(H), P(S), ES, E of interfaces and measured auxiliary earthing rods.

Data Upload

The stored data can be uploaded to computer. Make good connection of computer with RS232 communication wire of the tester, switch on the tester and run monitoring software, and if the software displays that interface is open and the connection is successful, then it can read the stored historical data, upload to company and preserve.

Monitoring software has the function of online real-time monitoring and historical inquiry, dynamic display, with alarm value settings and alarm indicator, and the function of historical data access, reading, preserve, print and other functions.

Battery Replacement

• Switch off; making sure that the Tester is under switch-off state.
• Loosen the four screws on battery cover at the bottom of the Tester, and open battery cover.
• Replace new battery, pay attention to battery polarity and specification, close battery cover, and fasten screw.
• Switch on verification, otherwise re-operate.