Hioki 3283 - Page 26

10
Chapter 2 Measurement Procedure
NOTE
･ Do not input a current which exceeds the
maximum continuous input rating.
･ When the clamp is open and while the range
is being changed, an indicated value in the
range of tens may appear; this is not a
malfunction.
The indication goes progressively to zero, but
this make take a little time. Beginning
measurement before the display reaches zero
has no effect on measurement.
【Checking for insulation faults】
Normally, for a type 2 grounding installation
of a transformer, the measurement will first
be made to check for overall circuit leak
current in the ground lead (a). Current
changes can be used to diagnose the leak
current condition.
When leak current has been detected, the
measurement should proceed from the power
source towards the load, using overall
measurement.
1. If an insulation fault in the wiring has
occurred at position A in the illustration, leak
current will be detected at position b using
overall measurement, but not at position b'.
2. If an insulation fault in the load equipment
has occurred at position B in the illustration,
leak current will be detected at position c
using overall measurement, but not at
position c'.