Instantaneous Earth Measurements!

The Earth Resistance Tester Models 371 and 373 are the new generation of earth resistance measurement instruments.Both models measure earth rod and small grid resistance through any season, without the use of auxiliary earthing rods. Clamp-on earth resistance testers are used in multi-earth systems without isolating the earth system under test. The Models 371 and 373 simply clamp around the earthing conductor or rod and measure the resistance to earth. By performing measurements on intact earthing systems, the user also verifies the quality of the earthing connections and bonds. Resistance and continuity of earthing loops around pads and buildings may also be measured.

Both models include a current measurement function. The probe's high sensitivity enables measurement of leakage current flowing to earth or circulating in earth loops down to 1 mA and neutral currents to 30 Arms. This feature provides additional information which is becoming vital as distribution earthing networks carry higher levels of noise and harmonics which affect power quality.

Both models offer battery life information at power-up and Auto-Off for power management. Additional features are also displayed on the large LCD to ensure precise measurements. The Buzzer and Auto-Off features may be disabled from the push-buttons at any time.

The Model 373 offers an alarm function and a memory (logging) function. In the Alarm mode, the probe will audibly and visually indicate if the reading is beyond an input set point. The user may also have the alarm initiated above or below the set point. This alarm feature permits quick field checks where only "pass" or "fail" readings will suffice.

The memory function logs up to 99 measurements (Ohms or Amperes). This enables the user to conduct field surveys, and to retrieve and analyze the readings at a later time. The alarm settings and stored memory information are saved when the earth tester is turned off.

Rugged Construction
The Models 371 and 373 bodies are built of Lexan® for rugged use. The probe heads are encapsulated in a double-walled shell for extra strength and are reinforced at the body interfaces for enhanced field reliability.

Overall construction and mechanical design ratings such as drop test, shock and vibration, weather proofing against water projections or dust, meet or exceed IEC (International Electrotechnical Commission) standards. The products have also been designed to meet UL, CSA and GS safety approvals.

Ergonomic Design
The ergonomic body design permits one-handed operation. The guard provides additional strength, and prevents the hand from slipping or coming into contact with conductors under test. The Lexan®body construction provides strength. The LCD lens cover may be easily replaced if scratched. The sealed push-buttons directly access all test functions and are easily operated even with gloved hands.

  • Simple and fast clamp-on operation - no leads, no auxiliary rods or spacing requirements
  • Direct reading of earth resistance from 0.1 Ohm to 1200 Ohm
  • Direct reading of continuity and earthing loop resistance
  • Direct reading of earth leakage current from 1 mA to 30 Arms
  • New jaw design with large 32 mm (1.25") window accommodates up to 1000 MCM cables
  • Alarm function with adjustable set point and buzzer for quick field checks
  • Memory function to store 99 field measurements for later analysis

UL, CSA and GS approvals pending, meets IEC 1010-1 Rugged Lexan® head and body construction.