Ground Resistance Tester Extech GRT300 Portable

Description

Product Overview

The Extech GRT300 is a rugged, battery‑operated 4‑wire earth resistance and resistivity tester designed for professional field use. Housed in a durable black case, the instrument weighs 1.43 kg and measures 9.8 × 7.8 × 4.3 in, making it easy to transport. It offers four resistance ranges (2 Ω, 20 Ω, 200 Ω, 2000 Ω) with ±0.5% accuracy, automatic ranging, and a large dual‑line LCD that displays voltage, current, and resistance values clearly. The device includes automatic I and P spike checks, auto‑zero adjustment, data hold, and an auto‑power‑off feature to conserve battery life. Powered by eight AA alkaline batteries (included), the GRT300 also measures AC earth voltage up to 300 VAC (40‑500 Hz) with over‑range capability and low‑battery indication.

Usage

The GRT300 excels in environments where reliable grounding verification is critical. Electricians use it to test grounding electrodes on residential and commercial installations, while contractors rely on it for site‑wide earth resistance surveys before equipment commissioning. Utility workers employ the meter for sub‑station grounding checks, and facilities maintenance teams use it to troubleshoot grounding issues in HVAC and fire‑suppression systems. Its 4‑wire, 3‑wire, and 2‑wire testing flexibility accommodates a wide range of standards and local codes, making it suitable for both new construction and retrofit projects.

Why Choose Us

Extech is a trusted name in measurement technology, and the GRT300 reflects that reputation with CE certification and a two‑year warranty. The instrument’s robust construction resists drops and harsh weather, while the included hard carrying case protects it during transport. Integrated safety features such as automatic spike detection and zero adjustment reduce user error, and the intuitive interface shortens training time. With the GRT300 you receive a complete testing solution—test leads, alligator clips, four auxiliary earth bars, and batteries—so you can start measuring immediately.

Key Features

• Four resistance ranges up to 2000 Ω with ±0.5% accuracy for precise grounding verification.
• Supports 2‑, 3‑, and 4‑wire test configurations to meet diverse code requirements.
• Large dual‑line LCD with auto‑ranging, data hold, and automatic I/P spike checks.
• Measures AC earth voltage up to 300 VAC (40‑500 Hz) with over‑range capability.
• Complete kit includes test leads, alligator clips, four earth bars, hard case, and eight AA batteries.

FAQ

What battery life can I expect?

The GRT300 provides up to 30 hours of continuous operation on eight AA alkaline batteries, with an auto‑power‑off after 10 minutes of inactivity to extend life.

Can I use the meter for soil resistivity measurements?

Yes, the GRT300’s 4‑wire configuration and selectable ranges make it suitable for both earth resistance and soil resistivity testing.

Is the device calibrated?

All units are factory calibrated to meet CE standards. A calibration certificate is included, and the meter features automatic zero adjustment for ongoing accuracy.

What safety standards does the GRT300 meet?

The instrument complies with IEC 61010‑1 for safety and is CE marked, ensuring it meets European safety, health, and environmental protection requirements.

How durable is the carrying case?

The hard‑shell case is impact‑resistant and water‑repellent, protecting the meter and accessories from drops, dust, and moisture during field work.