General Tools and Instruments CA10 - Manual (Page 12)

TESTING GROUND FAULT CIRCUIT INTERRUPTERS (GFCIs)
The CA10 can measure how much current it takes to trip a GFCI, and how
quickly it responds to a condition that should cause a trip. It does so by placing
a resistance across the circuit’s live and ground lines, generating a current
between them. According to UL, it should take no more than 5mA to trigger a
trip. The CA10 measures and displays the level of triggering current (in mA) and
the response time (in ms).
To select the GFCI test, press the FUNC button until GFCI is highlighted. Then
plug the free end of the test cable into any outlet equipped with a GFCI. To
initiate the test, press the TEST button. During testing, the display will show the
word TEST on the top line. If the device fails to be triggered, the analyzer will
stop testing automatically after 6.5 seconds.
The table below shows the normal measurement result of GFCI testing. It also
lists possible causes of, and remedies for, an abnormal result.
Notes: 1) Before testing, remove any heavy loads from the circuit to avoid
producing an inaccurate test result. 2) A ground connection is required to test
GFCIs in 2-wire systems.
TESTING OUTLET WIRING
The CA10 automatically checks the wiring of any outlet it is plugged into. The
upper part of the display contains the following arrangement of three circles: N
stands for the neutral conductor, L for the live conductor, and E for the earth
(ground) conductor.
If the outlet’s wiring is normal, all three circles will be filled in, as shown in the
table on the next page. Different combinations of filled in (on), empty (off) and
flashing circles indicate specific faults.
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Parameter
GFCI reliability
and response
time
Normal
Measurement
Result
GFCI trips within
specified time
Actual Result
GFCI is too slow
to trip
GFCI fails to trip
Possible Cause
of Abnormal
Result
GFCI is installed
improperly
GFCI is defective
Remedy
Check that installation
complies with
manufacturer’s
requirement and relevant
standards
Repair or replace GFCI