The Extech GRT300 is a professional 4-wire ground resistance tester that supports 2-, 3-, and 4-wire measurement methods for high-accuracy earth ground testing. Features include auto-ranging, automatic spike checks, dual-line LCD, and AC earth voltage detection. Complete with 4 earth bars, test leads, and hard case—ideal for telecom towers, substations, and lightning protection systems.
- 4 ranges: 2Ω / 20Ω / 200Ω / 2000Ω
- 2-, 3-, and 4-wire testing modes
- Automatic I & P spike integrity checks
- AC Earth Voltage: 0–300VAC
- Autoranging with 0.01Ω resolution
- Test Hold, Auto Zero, Data Hold
- Includes 4 earth bars, leads, 8x AA batteries, and hard case