Extech MG500 Operating Manual

USER MANUAL

10KV Digital High Voltage Insulation Tester

Model MG500

Additional User Manual Translations available at www.extech.com

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Introduction

Thank you for selecting the Extech Instruments Model MG500. This device is shipped fully tested
and calibrated and, with proper use, will provide years of reliable service. Please visit our website
(www.extech.com) to check for the latest version of this User Guide, Product Updates, and
Customer Support.

Safety

International Safety Symbols

This symbol, adjacent to another symbol or terminal, indicates the user must refer to the manual for
further information.

This symbol, adjacent to a terminal, indicates that, under normal use, hazardous voltages may be
present

Double insulation

CAUTION RISK OF ELECTRIC SHOCK

This tester has been designed with safety in mind. However, no design can completely protect
against incorrect use. Electrical circuits can be dangerous and lethal when a lack of caution and
poor safety practices are used.

Do not take field measurements on either power system grounding during periods of lightning
activity, or any non-insulated system or non-insulated circuit. In the event that lightning occurs,
stop all testing and isolate and remove any temporarily installed test spikes or test leads.

Preparations for testing power system grounding (or close to it) can leave personnel vulnerable to
exposure caused by faults at, or fed from, the system under test, transferred potentials from
remote test grounds, and inadvertent line energizing. Always insulate the device under test.

While the probability of such occurrences is low, personnel safety will, nevertheless, be
enhanced by the following:

When working near high tension systems rubber gloves and shoes should be worn. Work on
clean, dry crushed rock or an insulating blanket. Avoid bare hand-to-hand contact between
the tester and extended test leads.

When using the tester with test leads, ensure that they are safe and properly authorized.
Disconnect the tester from any external circuit when checking or changing the fuse and/or
batteries.

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CAUTION! READ THE MANUAL

Follow the instructions in the Manual for every measurement type. Read and understand the
general instructions before attempting to use this instrument.

SAFETY CHECK

Before using the tester check the condition of the test leads.

The test leads must be free of cracks or any damages and must be insulated.

Always disconnect the test leads when changing the batteries

Always double check the lead connections before making any measurements. For increased
safety, use fused test leads (optional).

Do not touch exposed wiring, connections or other "live" parts of an electrical circuit. If in doubt,
check the circuit first for voltage before touching it.

THIS INSTRUMENT SHOULD ONLY BE USED BY COMPETENT, SUITABLY TRAINED
PERSONNEL.

CAUTION! RISK OF ELECTRIC SHOCK

CAUTION! READ THE MANUAL

Electricity can cause severe injuries even with low voltage or current. It is extremely important that
the following information be read before using this High Voltage Digital Insulation Meter.

This instrument must only be used and operated by competent trained personnel and in strict
accordance with the instructions and safety practices. Liability is not accepted for any damage or
injury caused by misuse or non-compliance with instructions and safety procedures.

This instrument must not be used on live circuits. Ensure all circuits are de-energized before
testing.

Never open this High Voltage Digital Insulation Meter except for battery replacement (See
Battery Replacement section).

Always inspect this High Voltage Digital Insulation Meter and test leads before using for any
sign of abnormality or damage. If any abnormal conditions exist (broken test leads, cracked
case, display faulty etc...) do not attempt to take any measurement or use the tester. Return
the Meter for service.

This Variable High Voltage Digital Insulation Meter has a live circuit warning beeper. If it is
connected to a live circuit, a rapid pulsating tone will sound and a warning message will be
displayed. In this case, stop testing and immediately disconnect the instrument from the
circuit under test.

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Features

• Insulation Resistance Testing

This digital insulation resistance tester will measure insulation resistance from 800k ohms to
500G ohms using Dynamic Auto-ranging technology. Test voltages range from 500V to 10kV
in 500 Volt steps. This instrument also employs an Auto-Discharge utility.

• DAR: Dielectric Absorption Ratio Testing

The Dielectric Absorption is the ratio of the Insulation Resistance, measured at 60 seconds,
divided by the Insulation Resistance measured at 30 seconds).

DAR = Resistance measured at 1 minute / Resistance measured at 30 seconds

• PI: Polarization Index Testing

The Polarization Index is the ratio of the Insulation Resistance measured at 10 minutes
divided by the Insulation Resistance measured at 1 minute.

PI = Resistance measured at 10 minutes / Resistance measured at 1 minute

• Automatic Discharge of Capacitive and Inductive Circuits

This instrument will automatically discharge all circuits, charged by the tester, upon
completion of a test. The discharge can be observed on the instrument’s bargraph display.

• Automatic Battery Test

When the instrument is first powered ON, a test circuit applies a heavy current draw on the
batteries for a few seconds and measures the voltage in order to determine the capacity of
the batteries. The result is shown on the display.

• Normal Operation Mode Considerations

This instrument uses Dynamic Current Auto-ranging technology. The bar graph will

display the voltage that is stressing the insulation during the first 30 seconds of a test and
during the discharge of the circuits at the end of the test. The display will also show the
elapsed time from the start of the test and the total time, even after the testing has stopped.

• Supplemental Features

o Insulation Resistance auto-ranging on all Voltage ranges
o Automatic DAR calculation
o Automatic PI calculation
o Ener-Save™ Mode conserves battery energy during Insulation Resistance testing
o Overload protection
o Low battery indicator
o Auto Off feature
o Warning of external voltage presence (>500VAC or VDC)

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1

2 3 4 5 6 7 13 9 10

12 8 11

Description

1. Negative High Voltage (HV) Terminal

(Earth Ground)

2. Dot Matrix Display window

3. GUARD connection Terminal

4. Positive High Voltage Line Terminal

5. 10KV test voltage preset button

6. Power OFF button

7. Voltage adjustment button (-)

Note: Battery compartment located on bottom of instrument and test lead compartment
located behind the upper faceplate.

8. 5KV test voltage preset button

9. TEST START/STOP button

10. 2.5KV test voltage preset button

11. 500V test voltage adjust button (+)

12. Power ON button

13. 1KV test voltage preset button

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