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22
Fault localization and trouble shooting
Measurement
Item
Normal
measurement
result
Fault
measurement
result
Possible
cause
Trouble
shooting
Check the
circuit and
install
the RCD
according
to the
manufacture
requirement
and
relevant
standard
The RCD
is
installed
improperly
Fail to be
triggered
within
the
specified time
RCD
is triggered
within the
specified
time
RCD test
RCD goes
wrong
Repair or
replace RCD
Fail to
be triggered
(Invalid test)
Triggering time formula specified by UL: T = (20/I)
1.43
T: Triggering time (Unit: second)
I: Triggering current (Unit: mA)
GFCI test
During the GFCI test, the analyzer will generate a low
current between live line and earth line by means of a
fixed resistance, which will affect the current balance
between live line and zero line. The GFCI shall response
to the current imbalance by cutting off the power. The
analyzer will display the value of the current triggered
(mA) and response time (ms).
The word “TEST” will be displayed when the “ ” key
is pressed, which means the test is in the process.
GFCI shall be triggered within the specified index to cut
off the power of the circuit under test. If the GFCI fails to
be triggered, the analyzer will stop testing automatically
after 6.5 seconds. Analysis on GFCI shall be made
according to the test result to see if it goes wrong, is
installed properly or protects the circuit effectively.
Notes:
1. Check the circuit to see if there is heavy load
over the circuit before testing, if necessary, turn
off the load to avoid wrong test result.
2. Earth connection is required when the GFCI is
tested in the 2-wire system (without earth line).
