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Installation
Preparation for Installation
Prior to installation of switchgear, study this instruction book
and the switchgear drawings, such as general arrangement,
three line diagram, schematic diagrams, wiring diagrams,
installation instruction drawing, panel arrangement and panel
arrangement bill of material, nameplate engraving list, and
accessories drawing. Special attention should be given to the
foundation information contained in this manual as well as the
information provided on the equipment drawings. Be sure that
the foundation conforms to the requirements described in this
manual and the general arrangement drawing.
Foundation-General Requirements
Prior to installation of the switchgear, careful design, planning
and construction of the foundation or base on which the
switchgear will rest must be made. A thorough analysis and
careful construction may alleviate many problems at the time
of installation, and during operation. It is important that a true
and level surface be provided, capable of supporting the
weight of the switchgear and other related equipment.
If the switchgear cannot be lowered over conduits because of
headroom or other restrictions, conduit couplings may be
grouted in flush with foundation, and conduit nipples added
after the switchgear is in place.
Conduits should be capped during construction to prevent
entry of dirt, moisture and vermin.
All sill channels, bed plates, shims and anchoring hardware are
furnished by purchaser unless covered by contract.
Indoor Foundations
As it is difficult to obtain a true and level floor on a concrete
slab, it is highly recommended that 4" (minimum) sill channels
be grouted into the floor as shown in Figure 7. The surface of
the sills should be slightly above floor level. The surfaces of
the sills must be level and in the same horizontal plane within
1/16" (1.6mm). There should be no projection above this plane
within the area covered by the switchgear. If the floor or sills
do not meet this requirement, it will be necessary to use
shims when installing the switchgear on the mounting surface.
Figure 7 illustrates the location for sill channels for anchoring
indoor switchgear. Cubicles may be anchored to sills by use of
1/2" (or 12mm) diameter anchor bolts, or welded in position.
Courtesy of NationalSwitchgear.com
Outdoor Foundations
Whichever type of foundation is used (e.g., concrete slab, sill
channels, piers or pilings), it must have smooth and level sur-
faces. Surfaces supporting the switchgear must be in the
same horizontal plane within 1/16" (1.6mm). If these condi-
tions are not met, it will be necessary to use shims when
installing the switchgear.
For outdoor switchgear, support shall be provided at each end
and at the side of every second cubicle, so that the span
between supports does not exceed 36" (914mm). Refer to
Figures 8 and 10, and the switchgear general arrangement
drawing for locations of support and anchoring points. If pilings
are used, the diameter is to be determined by purchaser, how-
ever, they should not be less than 12" (305mm) diameter for
sufficient contact, room for anchor bolts, and grouting in of
bed plates (if used). All shipping splits must be properly sup-
ported.
Any conduits which are installed in concrete must be perpen-
dicular to switchgear mounting surface. Conduits should
extend a minimum of 6-3/4" (171mm) to a maximum of 7-1/2"
(190mm) above mounting surface. This will allow the conduit
to enter the cubicle and exclude entry of water and rodents.
Figures 8-9 show the method of anchoring outdoor Shelter-
Clad (walk-in) switchgear, and Figure 10 shows the method of
anchoring outdoor non-walk-in switchgear.
Important: In the switchgear primary entrance area, steel
reinforcing rods or mesh in concrete must not pass through
the space shown on the general arrangement drawing,
even though cored or bored holes in concrete may miss
rods or mesh. A single phase of a system should not be
encircled by ferrous metals.
9
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