Hioki ST5540, Instruction Manual, Page: 48 / 326

3.5 Pre-Test Inspection
42
Fuse inspection (when using modes other than Earth leakage current
and protective conductor current modes)
2
The current detection circuit in the instrument contains a fuse. Should the fuse blow due to incorrect wiring
or an over-current condition, the instrument may no longer be able to detect current. Before use, make sure
that the fuse is not blown.
Required items
• A device for measuring impedance
(for example, a tester)
(1) Select network E in the Network Select screen and select
Enclosure - Enclosure leakage current.
(2) Use a tester to measure the impedance between
the T1 and T2 terminals on the front panel.
(Or place the tip of test leads connected to the T1 and T2
terminals on the tester to measure.)
(3) Check that an impedance value of 1015

10

is obtained.
When the tester is connected to the T1 and T2 terminals,
the instrument measures the leakage current going through the tester.
The impedance is not
1015

10

.
The fuse at the T2 terminal on the front of the
instrument may be blown, or a non-specified
fuse may be inserted. Replace the fuse.
See "11.3 Replacing Fuses" (p. 282)
Network E : Enclosure-Enclosure
leakage current measurement screen
Check the line power supply of the equipment under test.
(1) Press in the initial screen.
(2) Turn on the circuit breaker of the instrument. (p. 31)
(3) Press to display the connection/VA check
screen.
(4) The check is made automatically.
(5) Press to return to the system screen.
Supply power via LINE IN and turn the circuit breaker On as a
connection / VA check will not otherwise operate normally. Always
confirm this before performing a connection / VA check.
Inspection complete
(When network B2 is selected(p. 43))
Inspecting line power supply for the equipment under test
3
An "NG" appears
Press to display the screen that shows advice
concerning the present condition. According to the
displayed advice, check the current consumption,
power cord connection, and other aspects of the
equipment under test.
See "About the NG Indication" (p. 44)
Press or to select
whether the check is to be conducted
each time power is turned.
The impedance is an
overflow
The impedance is about 15

.
(The fuse is not blown.)
Remove the fuse from the T2 ter-
minal, and directly measure the
fuse resistance.
The impedance is
not about 15

.