Extech MG325 CAT IV Insulation Tester/True RMS MultiMeter

Extech logo

2000 GOhm/1000V Insulation Tester/DMM with Datalogging

Combines a 200GΩ/1000V high range Insulation Tester with a full-featured True RMS MultiMeter in a single, compact instrument. CAT IV-600V safety rating ensures the highest level of protection.

CAT IV    CE    1 Year

PDF Logo    MG325 Datasheet
PDF Logo    MG325 Users Manual
If you would like more information regarding this product, simply email us here.
  • This field is for validation purposes and should be left unchanged.
SKU: Extech MG325 Categories: , Tags: ,

The Extech MG325 features a rugged design for heavy duty use. The MG325 measures Insulation Resistance, AC/DC Voltage, Frequency, Leakage Current, Low Resistance, Continuity, and Capacitance. Insulation Resistance tests are automatic ranging with 5 test voltages from 50V to 1000V. The MG325 can store and recall up to 99 measurements. The Extech MG325 is suitable for measuring the insulation resistance.

Extech MG325 Features:

  • DC and True RMS AC Voltage Measurments to 600V
  • CAT IV-600V safety rating
  • Insulation Resistance Measurements up to 200G
  • Frequency of the AC Voltage
  • Leakage Current Insulation test mode
  • Capacitance Measurements
  • Low Resistance and Continuity Measurements with ZERO function
  • Auto Ranging measurments
  • Polarization Index (PI) and Dielectric Aborption Ratio (DAR) tests
  • Five (5) Insulation Resistance test voltages (50, 100, 250, 500, and 1000V)
  • Insulation Resistance tests in 10% voltage steps (from 50% to 120% of range)
  • Eight (8) Insulation Resistance measurement ranges (automatic ranging)
  •  Pass/Fail Comparator function for Insulation Resistance and Continuity
  • Auto-discharge at end of test
  • Output voltage alert light and display symbols
  • Hand’s free test lock feature Manually store and recall up to 99 readings
  • Overload indication
  • Remote test probe for controlling the TEST button remotely
  • Test leads, alligator clips, batteries, user manual, and case included
 Extech MG325 Specifications :    
Function Range Resolution Accuracy
DC Voltage ±600V 0.01V to 1V ±(2.0% reading + 3 digits)
AC Voltage 0~600V 0.01V to 1V ±(1.5% reading + 5 digits)
Specified from 5% of range to 100% of range
Input impedance: 10MΩ
Frequency 45~400Hz (unspecified for frequency >400Hz) Input protection: 600V DC and AC rms
Frequency 45~1kHz 0.1Hz ±(0.1% reading + 3 digits); 45~450Hz
Frequency measurements are shown for ACV tests in the auxiliary display area Measurements 450Hz~1kHz are for reference only; accuracy not specified
Continuity 0.01~100Ω
(@ 20mA test current)
0.01~0.1Ω ±(1.5% reading + 5 digits)
(@ 200mA test current)
0.01~0.1V ±(1.5% reading + 4 digits)
Continuity threshold 30Ω (programmable ON/OFF continuity buzzer)
Open Circuit Voltage: 5V approximately
Resistance 0.001k~10MΩ 0.001kΩ.~ 0.1MΩ ±(3.0% reading + 3 digits)
Capacitance 0.1nF~500µF 0.1nF~0.1µF ±(5.0% reading + 5 digits)
Insulation Resistance Measurements
Test Voltage Range Min. Resolution Accuracy
50V 0.00M~0.99GΩ
0.01MΩ ~ 0.01GΩ
0.01GΩ ~ 0.1GΩ
±(3% + 3 digits)
±(3% + 3 digits) reading; ±4%/GΩ
100V 0.00M~0.99GΩ
0.01MΩ ~ 0.01GΩ
0.01GΩ ~ 0.1GΩ
±(3% + 3 digits)
±(3% + 3 digits) reading; ±2%/GΩ
250V 0.00M~0.99GΩ
0.01MΩ ~ 0.01GΩ
0.01GΩ ~ 0.1GΩ
±(3% + 3 digits)
±(3% + 3 digits) reading; ±0.8%/GΩ
500V 0.00M~0.99GΩ
0.01MΩ ~ 0.01GΩ
0.01GΩ ~ 0.1GΩ
±(3% + 3 digits)
±(3% + 3 digits) reading; ±0.4%/GΩ
1000V 0.00M~0.99GΩ
0.01MΩ ~ 0.01GΩ
0.01GΩ ~ 0.1GΩ
±(3% + 3 digits)
±(3% + 3 digits) reading; ±0.2%/GΩ
Short-circuit current < 2mA
250V DC and AC rms input limit
Insulation Resistance Test Voltage Outputs
Output Voltage Test Steps (50~120%) Load Overload Test current Short-circuit current
50V (0%~+20%) (25~60V) 50kΩ 250VAC/DC 1mA ≤2mA
100V (0%~+20%) (50~120V) 100kΩ 250VAC/DC 1mA ≤2mA
250V (0%~+20%) (125~300V) 250kΩ 250VAC/DC 1mA ≤2mA
500V (0%~+20%) (250~600V) 500kΩ 250VAC/DC 1mA ≤2mA
1000V (0%~+20%) (500~1200V) 1MΩ 250VAC/DC 1mA ≤2mA
Operating range per EN61557: 0.10MΩ~1.00GΩ (output voltage >/= 50V) Short-circuit current: 2mA (0%~50%)
Leakage current accuracy: ± (10% + 3 digits)
Test voltage output step range is 50%~120% in 10% steps
Note: Accuracy is stated at 23°C (75°F) and 45~75% RH.
Note: Calibration interval: 1 year maximum
Note: Temperature coefficient: 0.1 x stated accuracy/°C
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.
General Specifications
Display                                      5999 count, backlit, LCD with bargraph
Ranging                                    Automatic
Storage capacity                      99 records (01-99)
Input Impedance                      >10MΩ
AC Response                           True rms
ACV Bandwidth                        45Hz to 400Hz
Over range indication              “>” is displayed in Insulation Resistance and Continuity modes
Auto Power Off                        After 10 minutes of inactivity
Polarity                                     Automatic (no indication for positive); Minus (-) sign for negative
Measurement Rate                   2 times per second, nominal
Low Battery Indication            “         ” is displayed if battery drops below operating voltage
Battery                                      Six (6) 1.5V ‘AA’ batteries
Consumption                           500mA (at a 1000V test voltage); 17mA in nominal conditions
Fuse                                          500mA/600V fast blow
Enclosure                                 Double molded, IP 40


Operating Temperature           0ºC~40ºC (32ºF~104ºF)

Storage Temperature              -20°C~60°C (-4°F~140°F)

Operating Humidity                 <85%

Storage Humidity                     <90%
Operating Altitude                   2000m (7000ft,) maximum
Weight                                       0.7kg (1.5 lbs.) with batteries
Size                                           225[L] x 103[W] x 59[D] mm (8.8[L] x 4.1[W] x 2.3[D] in.)
Safety:   This instrument is designed in strict compliance with safety standard IEC61010, overvoltage standard (CAT IV 600V) and pollution degree II.


There are no reviews yet.

Be the first to review “Extech MG325 CAT IV Insulation Tester/True RMS MultiMeter”