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DEH-41473
Section 7. Testing and Inspecting
General
After the equipment has been installed and all connections
made, it must be tested and inspected before it is put in
service. Although the equipment and devices have been
tested at the factory, a final field test must be made to be
sure that the equipment has been properly installed and that
all connections are correct.
WARNING: The equipment must be completely de-
energized while the tests are in progress.
Directions for testing relays, instruments, and meters are
given in the instruction manual furnished for each device.
The proper settings of the protective relays and circuit
breaker trip units or EntelliGuard Messengers are normally
determined from a complete power system coordination
study performed by the purchaser or their consultant;
therefore, the settings of these devices must be made by the
purchaser. When the equipment is shipped from the factory,
the time dial of all inverse-time induction disc relays (i.e., IFC
types) is set to zero to prevent contact bounce during
transportation.
WARNING: The trip setting adjustments of the trip unit
or EntelliGuard Messenger for each circuit breaker may be
at any setting when shipped from the factory and must be
correctly set prior to energization of the equipment.
General instructions for setting the relays are given in the
applicable relay or trip unit instruction manual. Directions for
Entellisys instrumentation is provided in DEH-501.
The extent of the tests on the equipment as a whole will
depend on the type and function of the equipment. Tests
which should be performed, however, include circuit breaker
operation, and switchgear meggering, phasing, and
grounding checks.
High-potential tests to check the integrity of the insulation are
not necessary if the installation instructions are carefully
followed. If local codes demand this test, or the purchaser
wishes to make high-potential tests, the voltage should not
exceed 75 percent of the IEEE factory test voltage.
For the power circuit, the IEEE factory test voltage is two
times switchgear rating plus 1,000 volts. See Table 7.1.
Potential and control power transformers must be
disconnected during high-voltage testing.
Table 7.1 High potential test values
Switchgear
ANSI Test Voltage,
Voltage Rating
ac RMS
600 V ac
2,200 V
480 V ac
1,960 V
240 V ac
1,480 V
©2016 General Electric. All rights reserved.
Courtesy of NationalSwitchgear.com
Field Test Voltage,
ac RMS
1,650 V
1,470 V
1,110 V
AKD-20 AR / Entellisys AR Low-voltage Switchgear
Key Interlocks
After initial installation of the switchgear equipment, all
necessary interlock keys should be inserted into the
appropriate locks and all spare keys should be stored in a
location in accordance with the owner's established
procedures.
CAUTION: Refer to the key interlock schematic included
in the summary furnished with the equipment to determine
the sequence of operation and the correct number of
operating keys required. This precaution is necessary since
the improper use of spare keys will defeat the interlocking
scheme.
Breaker Operation Test
All compartments housing EntelliGuard circuit breakers have
a TEST position in which the breaker primary contacts are
disconnected while the secondary contacts are still engaged.
This TEST position permits complete testing of the electrical
control circuit without energizing the primary power circuit.
When the breaker is first put into service, its control circuit
must be thoroughly tested while in this position to make sure
that all closing and tripping circuits are complete and
functioning properly.
The TEST position is not suitable for inspection and
maintenance of the breaker and should therefore be used
only for testing breaker operation.
Refer to the appropriate breaker instruction manual for other
pre-operational checks on the breakers. See DEH-41304
(AKD-20 AR Only) or DEH-41526 (Entellisys AR Only).
EntelliGuard Trip Units (AKD-20 AR Only)
The calibration of the EntelliGuard trip unit should be checked
with the Type GTUTK20 test kit, a portable instrument
designed for the field-testing of EntelliGuard trip units. The
complete trip system is comprised of the following
components:
1.
Solid-state Trip Unit with Rating Plug
2.
Phase Current Sensors
3.
Flux Shift Magnetic Trip Device
4.
When applicable, a Neutral Sensor for units
containing a Ground Fault Trip Element.
All components, except the Neutral Sensor, are integrally
mounted in the circuit breaker. When used, the Neutral
Sensor is separately mounted in the bus or cable
compartment of the switchgear. In draw-out construction, it
Section 7. Testing and Inspecting
46
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