Earthing Resistance Measurement: A Complete Guide
Introduction
Performing earthing or grounding resistance measurement is crucial for ensuring electrical safety and system reliability. The key tool for this task is the Earthing Resistance Tester, designed to measure the resistance of the earth and verify compliance with grounding specifications.
This guide provides an overview of the Earthing Resistance Tester, its specifications, and the steps for performing earthing resistance measurement.
What is an Earthing Resistance Tester?
An Earthing Resistance Tester measures the earth’s resistance in ohms (Ω) to ensure that the grounding system meets safety and operational standards.
Key Specifications
| Feature | Details |
|---|---|
| Measurement Ranges | – Earth Resistance: 0–20 Ω, 0–200 Ω, 0–2000 Ω |
| – Earth Voltage: (50Hz, 60Hz) 0–200V AC | |
| Overload Protection | – Earth Resistance: 200V AC (10 seconds) |
| – Earth Voltage: 300V AC (1 minute) | |
| Accuracy | – Earth Resistance: ±2% reading ±0.1 Ω (20 Ω range) |
| – Earth Voltage: ±1% reading ±4 digits | |
| Safety Standard | IEC1010-1 CAT.III |
| Withstand Voltage | 3700V AC for 1 minute |
| Power Source | 6x AA Batteries |
| Accessories | – Test leads |
| – Auxiliary earth spikes | |
| – Simplified measurement probe | |
| – Carrying case and neck strap |
Features
- Dust and Drip Proof: Designed to IEC 529 IP54 standards.
- Simplified Two-Wire Measurement: Includes test leads for convenience.
- Safety Compliance: Meets IEC1010-1 safety standards.
- Automatic Warning: Alerts if auxiliary earth spike resistance exceeds tolerance.
- Non-Tripping Current: 2mA measuring current prevents tripping earth leakage breakers.
Instrument Layout
| Component | Description |
|---|---|
| LCD Display | Displays resistance and voltage readings. |
| Indicator LEDs | Shows operational status and error warnings. |
| Test Button | Activates the measurement process. |
| Range Selector Switch | Allows the selection of resistance or voltage ranges. |
Principle of Operation
Steps to Perform Earthing Resistance Measurement
- Preparation
- Ensure the Earthing Resistance Tester is calibrated.
- Verify all accessories, including test leads and auxiliary earth spikes.
- Connect Test Leads
- Connect the red test lead to the LINE terminal.
- Connect the black test lead to the EARTH terminal.
- Battery Voltage Check
- Press the blue button to check battery voltage. Replace batteries if the voltage is below the minimum level.
- Test Lead Check
- Short the test leads and press the test button. Ensure the reading shows zero resistance.
- Turn Off Power Supply
- Disconnect power supply to the system under test to avoid potential hazards.
- Set Up Measurement
- Insert auxiliary earth spikes into the ground at specified distances.
- Connect test leads to the earth electrode (E), potential electrode (P), and current electrode (C).
- Perform Measurement
- Select the appropriate range using the range selector switch.
- Press the test button and observe the resistance value on the display.
- Analyze Results
- Verify that the resistance value complies with safety standards (e.g., IEEE 43 recommends a minimum of 1 MΩ for motors).
Conclusion
The Earthing Resistance Tester is an essential tool for electrical safety and compliance. Regular testing ensures the grounding system operates effectively, reducing the risk of electrical hazards. Proper usage and maintenance of this instrument are critical for obtaining accurate measurements and safeguarding equipment and personnel.
Feel free to share your comments or questions below. Let’s learn and share knowledge to enhance electrical safety practices!
Hello.
I would like to know in more detail how to perform the earth resistence measurement.
In my case I can’t use auxiliar spikes because all is concrete around my test site.
Hello Luis..thanks for visit my blog…i suggest you to read my post TWO-POINT METHOD,I explain how to perform earth resistance measurement for concrete or tar surface…i hope it can help you…have a nice day
hello,
regarding equipment earthing do you have any idea how to be done? We do it the E (green) is connected to electrode,the P (yellow) is connected at any point and C (red) is connected to the earth terminal of the equipment the reading we got is 1.4 – 1.6 ohm so the testing is failed.. This procedure are correct? the result shall be not exceed to 1ohm.. What’s the remedy? If it is wrong what is the correct procedure?
Dear JJERNB,your step is correct..your reading also ok..The good range of earth resistance is 1 to 3 ohm.
i am in cambodai so how could i buy this earth test meter? how to measurment the earthing system and how to calculate it.
I need a circuit diagram of an earth tester