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.
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.
Operation Battery Voltage check 1. Press the "ON/OFF" button, if "Battery Low" appears on the display, replace the batteries. Earth Voltage measurement 1. Connect the test leads as shown below. E ES S H MAX. AC 300V P1 C1 1 P2 C2 2 (1) Earth electrode (rod) under test (2) Test spike 2. Press the "ON/OFF" button and wait for “Select Function” to appear on the display. 3. Press the "ACV" button and then the "TEST/STOP" button. 4. The earth voltage will be displayed on the display.
Earth Resistance measurement Note: The measured results may be influenced by inductive or capacitive coupling if the test leads are twisted or adjacent to each other. When connecting the Probes, keep the leads separated. Setup Insert the Potential spike and the Current spike (if required) as deep as possible into the soil. The distance between spikes must be 5 to 10 meters (16 to 32 feet). Four-terminal earth resistance measurements E ES S H P1 P2 C2 1 2 MAX.
Testing 1. Connect the test leads for 2, 3 or 4 terminal testing. 2. Press the ON/OFF button and wait for the “Select Function” screen to appear. 3. Press the "2P", "3P" or "4P" button that agrees with the setup. 4. Press "TEST/STOP" button to begin the test. 5. The meter will beep while the test is in progress (approximately 10 seconds) and then the reading will appear on the lower line of the display. Notes: "Rc" & "Rp" LED indications: Rc: No test current output. Check connections.
Maintenance 1 1. Rear cover 2. Battery 3. Fuse 2 3 Fuse Replacement 1. Disconnect the test leads from the instrument. 2. Remove the rear cover by removing two screws. 3. Remove and replace the fuse with the new one of the same value and size 0.1A/250V, 5 x 20mm. 4. Replace and secure the rear cover. Battery replacement When "Battery Low" appears on the display, replace the batteries. 1. Disconnect the test leads from the instrument and remove the rear cover and the batteries. 2.
Specifications Measuring Ranges Accuracy Earth Resistance Resolution Test Frequency Test Current Temperature & Humidity Power Source Dimensions Weight Fuse( Earth Resistance: 0-2Ω, 0-20Ω, 0-200Ω, 0-2kΩ Earth Voltage: 0-300V AC (40 to 500Hz) Earth Resistance: ±(2%rdg+3dgt) Earth Voltage: ±(2%rdg+3dgt) 0-2Ω : 0.01Ω 0-20Ω : 0.1Ω 0-200Ω : 1Ω 0-2kΩ : 0.01kΩ 820Hz 2mA Operating : 0 to 50°C (32 to 122°F) ≦80%R.H. Storage : -10 to 60°C (14 to 140°F) ≦80%R.H. 1.5V(AA) x 8 250(L) x 190(W) x 110(D)mm (9.84x7.5x4.
