“A Stitch in Time...”

Slight sparking may be encountered:
(1) When attaching the test leads to equipment in which the capacitance
has not been completely discharged
(2) during a test, arcing through or over faulty insulation
(3) Following a test when capacitance is discharged
CAUTION:
Do not use the instrument
in an explosive atmosphere.
Suggestions:
For (1) and (3): Arrange permanently installed grounding facilities and
test leads to a point where instrument connections can be made in a safe
atmosphere.
For (2): Use low-voltage testing instruments, or a series resistance.
For (3): Do not disconnect the test leads for at least 30 to 60 seconds
following a test, allowing time for capacitance discharge.
Connections for testing insulation resistance
of electrical equipment
The following diagrams show how to connect a Megger insulation tester to
various types of electrical equipment. The diagrams also show in principle
how equipment must be disconnected from other circuits before the
instrument is connected.
These illustrations are typical and will serve as guides for testing insulation
resistance of practically all types of apparatus and conductors.
Before proceeding with tests, read the article on Preparation of Apparatus
for Test, page 24.
REMEMBER! The Megger insulation resistance tester measures
whatever resistance is connected between its terminals. This may
include series or parallel leakage paths through insulation or over
its surface.
A STITCH IN TIME 27