Earth resistance testing verifies that electrical systems have a safe, low-resistance connection to ground — essential for protecting people from electric shock and equipment from fault damage. Choosing the right earth tester depends on your test method, the type of installation, and whether you need to disconnect the earth electrode to test it.
 

The 4 main earth testing methods
2-wire method — the simplest and quickest check, but less accurate. Used for fast site verification where a rough measurement is acceptable. The KEW 4300 is specifically designed for 2-wire simplified earth testing — ideal for contractors who need quick, portable checks.
3-wire (fall-of-potential) method — the standard method for accurate earth resistance measurement using auxiliary current and voltage probes driven into the ground. This is the method required for formal testing and commissioning. Recommended models: KEW 4102A, KEW 4105A, KEW 4105DL.
4-wire method — used for measuring very low earth resistance values accurately, eliminating lead resistance errors. Required for substation earth grids and high-integrity earthing systems. Recommended models: KEW 4106 (also measures soil resistivity).
Clamp-on method (no disconnection) — the most convenient method for testing multi-electrode earth systems (telecom towers, distribution poles, street lighting) where disconnecting the earth is not possible or safe. The clamp simply closes around the earth conductor. Recommended models: KEW 4200, KEW 4202.

Which model is right for you?
Quick site check, contractor use: KEW 4300 (2-wire, simple)
Standard 3-wire earth testing, industrial: KEW 4102A or KEW 4105A
Data logging with Bluetooth: KEW 4105DLBT-H
Soil resistivity measurement: KEW 4106
Multi-electrode systems, no disconnection: KEW 4200 or KEW 4202
Substation/utility: KEW 4106 (4-wire, resistivity)

What resistance value is acceptable?
As a general guide for India: residential/commercial installations should achieve less than 5 ohms; industrial installations typically require less than 1 ohm; utility and substation earthing systems often require less than 0.5 ohms. Always refer to IS 3043 (Code of Practice for Earthing) for specific requirements.

All Kyoritsu earth testers come with a 3-year warranty and are available from KEW India — India's official authorised distributor.