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SE-330
Neutral-Grounding-Resistor
Monitor
Rev.
9-A-112913
9.4 G
ROUND-
F
AULT
P
ERFORMANCE
T
EST
To meet the requirements of the National Electrical
Code (NEC), as applicable, the overall ground-fault
protection system requires a performance test when first
installed. A written record of the performance test is to be
retained by those in charge of the electrical installation in
order to make it available to the authority having
jurisdiction. A test-record form is provided for recording
the date and the final results of the performance tests.
The following ground-fault system tests are to be
conducted by qualified personnel:
a) Evaluate the interconnected system in accordance with
the overall equipment manufacturer’s detailed
instructions.
b) Verify proper location of the ground-fault current
transformer. Ensure the cables pass through the
ground-fault-current-transformer window. This check
can be done visually with knowledge of the circuit.
The connection of the current-transformer secondary
to the SE-330 is not polarity sensitive.
c) Verify that the system is correctly grounded and that
alternate ground paths do not exist that bypass the
current transformer. High-voltage testers and
resistance bridges can be used to determine the
existence of alternate ground paths.
d) Verify proper reaction of the circuit-interrupting
device in response to a simulated or controlled ground-
fault current. To simulate ground-fault current, use
CT-primary current injection. Fig. 22a shows a test
circuit using an SE-400 Ground-Fault-Relay Test Unit.
The SE-400 has a programmable output of 0.5 to 9.9
A for a duration of 0.1 to 9.9 seconds. Set the test
current to 120% of GF TRIP LEVEL.
Fig. 22b shows a test circuit using an SE-100T
Ground-Fault-Relay Tester. The SE-100T provides a
test current of 0.65 or 2.75 A for testing 0.5- and 2.0-A
trip levels. Inject the test current through the current-
transformer window for at least 2.5 seconds. Verify
that the circuit under test has reacted properly. Correct
any problems and re-test until the proper reaction is
verified.
e) Record the date and the results of the test on the
attached test-record form.
NOTE:
Do not inject test current directly into CT-input
terminals 8, 9, 10, and 11.
NOTE:
For accurate trip-time measurement, the fault
current should not be re-applied for the time defined by the
GF TRIP TIME setting to allow the trip accumulator to
initialize.
