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13
Installation
01.4IB.26263B
Additional shipping members may have
been installed in the bus or primary area
to ensure against shipping damage. All
shipping members must be removed from
the switchgear compartments. All joints
must be properly tightened and insulated
before energizing the bus.
Mats, railing, etc. that are external to
metal-enclosed switchgear may be required
to meet local code. These items must be
provided by the purchaser.
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The station floor must be strong enough to
remain rigid and not sag under the weight of
the switchgear structure. The floor also must
be able to withstand the impact stress caused
by the opening of the circuit breakers under
short circuit conditions. The short circuit
impact load is approximately 1-½ times the
static load weight of the switchgear.
The purchaser must provide suitable means
for anchoring the switchgear to the floor. The
floor supporting the switchgear must be level
in order to avoid distorting the switchgear
structure and to align the switchgear
properly. The switchgear must be correctly
and completely aligned prior to applying final
anchors. Level foundations are desirable since
they automatically produce true, level, and
plumb switchboard installations. However,
the switchgear will operate satisfactorily on
a true and flat foundation that has a uniform
slope of no more than 1/8 inch in three feet.
The switchgear units must be placed on the
floor channels in such a manner that the base
of each unit rests directly on each of the floor
channels.
The floor channels should have a minimum
web dimension of 4 inches. The required
quantity and location of the floor channels
is shown on the drawings furnished with
the order. The spacing of the floor channels,
including the center channel, must be as
shown on the drawings. Even though the
switchgear is not anchored to the center
channel, its location is important to the proper
support and alignment of the switchgear units.
The floor channels must be level and straight
with respect to each other. Brass shims should
be placed under floor channels when leveling
is needed.
Care should be taken to provide a smooth, hard
and level floor underneath and in front of the
sections to facilitate installation and removal of
the circuit breaker.
When installing metal-enclosed switchgear
on existing floors, it will usually be desirable
to pour a newly finished floor with embedded
channels, or to cut slots in the floor for
embedding and leveling the supporting
channels.
The recommended practice is to weld the
switchgear structure to the floor channels,
using a tack weld at points indicated for
anchoring on the drawing. After welding, any
damaged paint should be removed and the
weld and surrounding metal should be painted
to deter corrosion. If welding facilities are not
available, the switchgear should be bolted to
the floor channels.
