USER MANUAL Insulation Resistance Tester With Continuity and AC Voltage modes Model MG310
Introduction Thank you for selecting the MG310 Insulation Resistance Tester. This meter measures insulation resistance, continuity, and AC Voltage. The MG310 is CAT III 600V AC and ideal for measuring insulating materials and electrical equipment such as transformers, cables, switches, and appliances. Applications include maintenance, testing, and inspection. Proper use and care of this meter will provide many years of reliable service.
Warning If the instrument exhibits faulty operation please discontinue use and have the instrument serviced. Be extremely careful when the instruments is measuring voltages that exceed 33V AC rms, 46.7V AC rms, or 70VDC; electrical shock is possible. When high resistance measurements are conducted, stray electrical in circuits under test must be discharged. Do not replace the batteries when the instrument is wet.
Meter Description 4 3 2 1 6 7 8 5 1. 2. 3. 4. 5. 6. 7. 8. 9. 9 EARTH terminal for Insulation Resistance and Continuity testing. GUARD terminal for ACV and Continuity testing. V terminal for ACV testing and Self‐Test mode. LINE Terminal for Insulation Resistance testing and Self‐Test mode.
Display Description 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.
INSULATION RESISTANCE MEASUREMENTS CAUTION Before taking measurements disconnect the unit under test from all power sources and isolate it from any stray resistance. Do not short circuit the test leads when voltage is output from the meter. Allow sufficient time between tests for devices under test to stabilize. When red and black clips are connected to the circuit under test, high voltage is output from the LINE jack and current from the EARTH jack.
POLARIZATION INDEX (PI) TESTING Read and understand all operations and safety information contained in the Insulation Resistance (IR) measurement section above and the Safety section before continuing. 1. Connect the meter to the device under test as shown in the test section above. 2. Select the desired output test voltage using the rotary function switch (250/500/1000V). 3. Use the PI/DAR button to access the PI test mode. 4.
ACCURACY SELF‐TEST FUNCTION The MG310 features a 10MΩ accuracy check feature for the Insulation Resistance mode. To verify the accuracy: 1. Connect a wire jumper to the meter between the LINE (4) and V (3) terminals as shown in the accompanying illustration. 2. Select one of the three test voltage (250/500/100V) switch positions. 3. Press the TEST button to begin the test. 4. When testing is complete, the meter will display 10.0MΩ (± 0.1MΩ).
AC VOLTAGE MEASUREMENTS WARNING: Risk of Electrocution. The probe tips may not be long enough to contact the live parts inside some 240V outlets for appliances because the contacts are recessed deep in the outlets. As a result, the reading may show 0 volts when the outlet actually has voltage on it. Make sure the probe tips are touching the metal contacts inside the outlet before assuming that no voltage is present. CAUTION: Do not measure AC voltages if a motor on the circuit is being switched ON or OFF.
Maintenance WARNING: To avoid electric shock, disconnect the test leads from any source of voltage before removing the back cover or the battery or fuse covers. WARNING: To avoid electric shock, do not operate the meter until the battery cover is in place and fastened securely. This instrument is designed to provide years of dependable service, if the following care instructions are performed: 1. KEEP THE METER DRY. If it gets wet, wipe it off. 2. USE AND STORE THE METER IN NORMAL TEMPERATURES.
Specifications Function Range Resolution AC Voltage 30 to 600V 1V Accuracy (2.0% reading + 3 digits) AC voltage specified from 5% of range to 100% of range Continuity 0.00~220 (2.0% reading + 3 digits) 0.01 < 20 (approx.) the buzzer will sound If the circuit is open >220 is displayed Open‐circuit voltage: 5V approx. Insulation Resistance Rated voltage 250V Output 500V Output 1000V Output Range 0.00M~5.5G 0.00M~5.5G 0.00M~5.
Note: Accuracy is stated at 73.4oF (23oC) and 40~75% RH. Note: Accuracy specifications consist of two elements: (% reading) – This is the accuracy of the measurement circuit. (+ digits) – This is the accuracy of the analog to digital converter. Display Backlit LCD (max. reading 1999) Low battery indication Battery icon Overload indication Insulation resistance testing > 5.5G displayed when the meter range has been exceeded. Range selection Automatic appears when batteries need to be replaced.
