Testing And Final Inspection - ABB MNS-SG Operation And Maintenance Manual

! DANGER
Always use properly insulated tools and instruments
during commissioning. Short circuit currents in low-
voltage switchgear are typically very high. Depending on
trip settings, high short circuit currents with long
durations can occur.
! DANGER
Follow all codes and regulations related to servicing and
installing electrical equipment. Failure to follow these
instructions can result in short circuits and electrical
arcing.
Check all of the following items related to the electrical
connections and systems before energizing the switchgear.
Ensure the electrical characteristics of the switchgear
-
(e.g., rated voltage, short circuit current rating, grounding
system, etc.) are compatible with the site conditions.
Inspect the withdrawable
-
instructions in the Inspect Units section of this manual.
Inspect the unit contacts, following the instructions in the
-
Inspect Units section of this manual.
Using the proper tool for each connection, verify the
-
tightness of all control and power terminals within the
units.
Insert all necessary fuses in the main and auxiliary
-
circuits, verifying that they match the apparatus list and
the circuit diagram.
Set to its lowest value the main circuit protective device
-
feeding the switchgear.
Set the units' protective devices to the specified values.
-
If present, verify that current transformers are properly
-
connected or short- circuited.
If an external control voltage is present, verify that it is
-
OFF.
38 MNS-SG Operation and Maintenance | Manual
breaker, following the
Close and latch all doors.
-
Test electrical insulation resistance. Conduct the test
-
phase-to-phase, phase-to- ground, and when applicable,
phase-to-neutral. Conduct the test with all unit -
disconnects in the OFF position. If the switchgear is
equipped with potential transformers (for metering, etc.)
remove the primary fuses prior to performing the test.
NOTE: When conducting an electrical insulation resistance
test, isolate equipment sensitive to high test voltages –
such as meters, solid state devices, motor winding heaters
and capacitor units. Following successful completion of the
test, reconnect all relays, operating voltages, circuits and
fuses.

4.11.3. Testing and final inspection

! DANGER
Disconnect the primary power source during testing.
Do not exceed the listed voltages for the voltage class of
the equipment under testing. Disconnect the shunt-
connected coils such as potential transformers.
Do not test solid-state sensors or relays with high voltage.
Disconnect solid-state sensors and relays before applying
voltage.
With the switchgear erected, assembled, and connected, do
the following:
1. Remove packing and shipping materials.
2. Make sure that all internal parts are clean and dry. If
moisture is present, dry with moving air and heat.
3. To check for damaged insulation, apply potential tests
to the primary bus. Potential tests should be conducted
phase-to-phase and phase-to-ground.