43
A K D - 20 A N D E NTE LLYS I S
LO W VO LTAG E S W I TC H G E A R
Indoor equipment
1. Anchoring by anchor bolts - Indoor equipment
are normally secured to their final mounting
surface by anchor bolts threaded into the
embedded channel sills, Fig. 4.20. The bolts were
loosely threaded into place before reassembling
the equipment shipping splits and connecting to
the close-coupled transformer, if appropriate.
The anchor bolts should now be tightened with a
torque of 35-40 ft-lbs.
2. Anchoring by weld - An alternate method
of anchoring the equipment to its foundation is
to weld the equipment to floor sills (or the floor
itself if constructed of steel). Several methods,
shown on Fig. 4.21, are available to the purchaser
for welding the equipment to the channel sills.
a. The front of the equipment is attached to the
embedded channel sills, Fig. 4.21, by two
3/16-inch fillet welds. It is recommended that two
welds, each 2-1/2 inches long (min.), be used for
each section to firmly tie the bottom width post
to the channel sill.
b. The rear of the equipment may be anchored
by one of three procedures:
The first method is by plug welds, Fig. 4.21, using
the anchor bolt holes in the rear sill angle. The plug
weld should receive a minimum 1/2-inch bead
around the entire circumference of the anchor
bolt hole.
A second method of securing the front and rear
sill angles to the channel sill is the use of two
linear fillet welds for each section. It is
recommended that each weld be 2-1/2 inches
long (min.) with a 3/16- inch fillet (min.).
A third method for anchoring the rear of the
equipment is to remove the rear sill angle from the
switchgear and weld the rear bottom width post
to the channel sill. These welds should, like the
front welds, have a 3/16-inch (min.) fillet and
each have a minimum length of 2- 1/2 inches.
Outdoor equipment
Outdoor equipment is anchored after
re-assembly of the separately shipped sections.
The four anchor bolts should be tightened with
a torque of 45-55 ft-lbs.
Caution: If the equipment is to be subjected
to operational or environmental (seismic)
shock loading, the factorymust be consulted
for anchoring recommendations.
Prudence: Si l'équipement risque
d'être soumis à une charge dynamique
opérationnelle ou environnementale
(sismique), veuillez consulter le fabricant
pour connaître les recommandations
d'ancrage.
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Fig. 4.20
Indoor equipment
anchoring
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Mounting arrangement
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Plan view
