MG500-en-GB_v1.3 3/17
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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.