The clamp-shaped ground resistance tester is controlled by a microprocessor to accurately detect the ground resistance. It uses a rapid filtering technology to minimize the interference. It is a commonly used and necessary instrument for telecommunication, electric power, meteorology, engine room, oil field, electromechanical installation and maintenance as well as industrial enterprise departments using electric power. Features: Easy to Operate: When measuring ground system with loop, there is no need to disconnect the ground wire without auxiliary electrode, safer and faster. Precision Clamp Head Design: Using precision iron core and winding, stable, precise and strong anti-interference. Clamp Size: 1.26"(32mm), large jaws with double insulation for extra safety. Data Storage Function: 500 sets of measurement results can be recorded, the "MEM" storage indication, flashing the "MEM" symbol indicating that the storage is full. Multi Practical Functions: New design, panel operation with 6 buttons, better performance. With real-time clock, data storage, data access, alarm, automatic shutdown and other functions. Widely Used: It is suitable for measuring all kinds of telecommunications, electric power, meteorology, machine room, oil field, power distribution lines, tower transmission lines, gas stations, factory grounding network, lightning rob and other grounding resistance. Specifications: Model: ST4100 / ST4800 (Optional) Material: ABS Function: Grounding resistance test, circuit resistance test, leakage current test Environmental Temperature and Humidity: 23 ± 5, lower than 75%RH Power Supply: DC 6V, 4 * 1.5V AA dry battery (not included) Measurement Method: Mutual feeling way Resistance Range: 0.010-500 (ST4100), 0.010-1200 (ST4800) Resistance Resolution: 0.001 Current Range: 0.00mA-30.0A (ST4800) Current Resolution: 0.01mA Clip Size: 55mm x 32mm Time Clock Feature: Have + ASynchronous Display: + AThe same screen display Display Mode: 4-bit LCD display, black screen design LCD Size: 46mm x 36mm Measure Time: 1 Time/second Data Storage: 500 groups, the "MEM" storage indication, flashing the "MEM" symbol indicating that the storage is full Data Access: The "MR" symbol indicates when reviewing the data Overflow Display: OL symbol indication when overrange overflow Disturbed Test: Automatic identify the interference signal, indicating the "NOISE" symbol when the interference current is high Alarm Function: Send an alarm prompt when the measured value exceeds the alarm set point Cell Voltage: Battery power is displayed in real time Auto Shut Off: It can be set to 5, 10, 15, 20 minutes, OFF, OFF means to cancel the automatic shutdown, the default is 5 minutes Power Dissipation: 115mA Max Working Temperature and Humidity: -10~40; lower than 80%RH Storage Temperature and Humidity: -20~60; lower than 70%RH Insulation Resistance: 20M above (Between the circuit and the housing 500V) Withstand Voltage: AC 3700V/rms (Between the circuit and the housing) External Magnetic Field: 40A/m External Electric Field: 1V/m Suitable For Safety Regulation: IEC61010-1(CAT III 300V, CAT IV 150V, degree of pollution 2); IEC61010-031; IEC61557-1 (earthing resistance) Item Size: 295 * 85 * 58mm / 11.61 * 3.35 * 2.28in Item Weight: 888g / 1.96lb Package Weight: 1970g / 4.34lb Package Size: 35 * 13 * 21cm / 13.78 * 5.12 * 8.27in Package List: 1 * Earth Resistance Tester 1 * Aluminum Case 1 * Measuring Ring 1 * User Manual (English)