GENERAL OPERATING INSTRUCTIONS
8
Safety note:
If a voltage greater than 25 V appears on the circuit under test the
instrument will default to a voltage measurement and display the
supply voltage.
On supply voltages over 50 V the instrument will prevent the
test button from performing an insulation test, protecting your
instrument from damage.
General functions
Voltage Testing on High Energy Systems
Use extreme care when using or measuring voltages above 30 V,
particularly in high energy systems. Fused test leads are available as
optional accessories for local situations where increased protection is
required. See accessories section.
Tests lock
The LOCK
L
indicates when an INSULATION test range is locked ON.
It is activated by holding down the [TEST] button, and pressing the LOCK
L
button.
Note:
See analogue section for MIT310A
Warning:
Hazardous voltages can exist on the insulation test range all the
time the [TEST] button is locked down.
Voltage warning (MIT300 only)
If a voltage exists on the circuit under test, the instrument will emit a
warning beep.
If a voltage greater than 50 V exists, testing will be automatically
inhibited.
Batteries
The Megger MIT300 series of instruments are supplied with batteries
fitted. When batteries become exhausted, refer to page 18, battery
replacement.
Warning:
Do not
switch the instrument on with the battery cover
removed.
Preliminary test lead check
Functional verification
1. Before each use of the instrument visually inspect the test leads, prods
and crocodile clips to confirm that their condition is good, with no
damaged or broken insulation.
2. Check continuity of the test leads by firmly shorting the leads together
and read the test lead resistance measurement directly from the display,
which should be less than 1.0 Ω.
Refer to page 10 for operation guide.
3.
Supply voltage
Using an approved method, ensure the circuit to be tested has been
fully disconnected from the supply prior to using the instrument.
PREPARATIONS FOR USE (ALL INSTRUMENTS)
