Technical Data
Effective: May 1998
Page
41
TD.44A.01.T.E
Cutler-Hammer
Magnum DS
Metal-Enclosed
Low-Voltage Switchgear
Typical Specification
Each breaker shall be equipped with a
microprocessor-based, true RMS sens-
ing trip device. The adjustments shall
be:
■
Long delay pickup between 40% and
100% of the trip rating
■
Long delay time between 2 and 24
seconds at 6 times trip rating
■
Short delay pickup between 2 and
10 times long delay trip setting,
short delay time between 0.1 and 0.5
seconds at 2.5 times short delay
pickup. Short delay protection shall
be defeatable, but only if instanta-
neous protection is activated. Both
“flat” and “I
2
t” protection shall be
provided. (Optional) Zone Selective
Interlocking.
■
Instantaneous pickup between 2 and
12 times trip rating. Instantaneous
protection shall be defeatable, but
only if short delay protection is
activated.
■
(Optional) Ground fault pickup
approximately 25% of sensor rat-
ing, and ground fault time between
0.1 and 0.5 seconds. Both “flat” and
“I
2
t” protection shall be provided.
Pickup shall not exceed 1200A,
regardless of circuit breaker maxi-
mum continuous rating. Ground
fault shall be field selectable for
residual, zero sequence or source
ground protection. Selectability
shall be made in the circuit breaker
compartment, not on the drawout
element, to maximize the flexibility
of interchangeable drawout power
circuit breakers. (Optional) Zone
selective interlocking shall be pro-
vided for Ground Fault protection.
It shall be possible to test and verify
the time and current characteristics
and trip circuit by means of a portable
plug-in test device.
Both electrically operated and manu-
ally operated breakers shall have
stored energy operating mechanisms.
The device to close the breaker shall be
by means of a mechanical pushbutton,
which insures positive control of the
closing operation.
Seismic
The switchgear assembly and circuit
breakers shall be suitable for and certi-
fied to meet all applicable seismic
requirements of (UBC) (The California
Building Code) for zone 4 application.
Guidelines for the installation, consis-
tent with these requirements, shall be
provided by the switchgear manufac-
turer and be based upon actual testing
of representative equipment. The test
response spectrum shall be based
upon a 5% minimum damping factor,
(Insert the following for UBC: a peak of
0.75g, and a ZPA of 0.38g), (Insert the
following for CBC: a peak of 1.8g, and a
ZPA of 0.45g). The tests shall fully
envelop this response spectrum for all
equipment natural frequencies up to at
least 35 Hz.
Factory Assembly and Tests
The switchgear shall be completely
assembled, wired, adjusted and tested
at the factory. After assembly, the
complete switchgear control and
instrumentation circuits shall be tested
for operation under simulated service
conditions to assure the accuracy of
the wiring and the functioning of the
equipment.
The main circuits shall be given a
dielectric test of 2200 volts for one
minute between live parts and ground
and between opposite polarities. The
wiring and control circuits shall be
given a dielectric test of 1500 volts for
one minute, or 1800 volts for one sec-
ond, between live parts and ground.
Note: Arrangement sketch and single
line diagram should accom-
pany the written specification.
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