Extech GRT300 Operating Manual

User Guide

4 wire Earth Resistance Tester
Model GRT300

Introduction

Congratulations on your purchase of Extech’s 4 Wire Earth Resistance Tester. The Model GRT300
has been designed and tested according to the IEC Publication 348, safety requirements for Electronic
Measuring Apparatus, EN 61010-1, EN 61326-1, EN 61557-1 , EN 61557-5 and other safety
standards. Proper use and care of this meter will provide many years of reliable service.

Safety Notes

• Read the all safety information carefully before attempting to operate or service the meter.

• Use the meter only as specified in this manual. Otherwise, the protection provided by the meter

may be impaired.

• Rated environmental conditions :

 Indoor & outdoor use.

 Installation Category IV 300V.

 Pollution Degree 2.

 Altitude up to 2000m.

 Relative Humidity 80% max.

 Ambient temperature 0-40°C.

Observe the International Electrical Symbols listed below :

Detector is protected throughout by double insulation or reinforced insulation.

Warning ! Risk of electric shock.

Caution ! Refer to this manual before using the detector.

Earth(ground) terminal.

Equipment complies with current EU directives.

WARNING

To avoid electrical shock, do not touch the terminals during tests

Never apply Voltage higher than 300V across P1 and P2 terminals.

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Features

• Microprocessor controlled with advanced safety features

• Two line LCD display

• Auto-Ranging

• Earth resistance testing with four ranges: 0-2Ω/0-20Ω/0-200Ω/0-2kΩ

• Earth voltage measuring range of 0-300Vac

• Automatic C spike check.

• Automatic P spike check.

• 2-wire test

• 3-wire test

• 4-wire test

• Auto power off

• Data hold

• Safety standard: EN 61010-1 CATIV 300V, EN 61326-1

Meter Description

1. C1 terminal
(Black test lead connection)

2. P1 terminal
(Green test lead connection)

3. P2 terminal
(Yellow test lead connection)

4. C2 terminal
(Red test lead connection)

5 Display

6. Rc LED

7. Rp LED

8. 2 Wire button

9. 3 Wire button

10. 4 Wire button

11. ACV button

12. Power button

13. TEST/STOP button

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3

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8 9 10 11 12 13

5

6
7

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