31
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
Foundation requirements
For optimum performance of your switchgear
equipment, the foundation requirements
expressed in this section should be strictly
adhered to.
Note: The foundation for the outdoor switchgear
must provide proper drainage of ground and/or
surface water accumulations away from
the equipment.
Remarque: La base sur laquelle repose
l'appareillage électrique extérieur doit offrir un
drainage approprié des accumulations d'eau dans
le sol et/ou en surface, à l'écart de l'équipement.
The foundation must be strong enough to prevent
sagging due to the weight of the switchgear
structure and to withstand the shock stress
caused by the opening of the breakers under fault
conditions. The shock loading is approximately
1-1/2 times the static load. The foundation must
be flat and level in all planes. Refer to Fig. 4.1 for
definition of flat and level.
Foundation preparation - indoor equipment
Refer to Fig. 4-2 along with the owner's foundation
construction drawings and the supplemental
installation drawings. Although the indoor
switchgear equipment can be mounted directly
on a smooth, level floor, it is recommended that
recessed steel channels be installed for supporting
the equipment. Anchor bolts and channels are to be
provided by the purchaser.
Note: When the equipment is installed on a
surface subject to impact (shock) loads due
to operating conditions or environmental
seismic (earthquake) conditions, the anchor
bolts should be fabricated of medium
carbon steel (grade 5 load rating).
Remarque: Lorsque l'équipement est installé
sur une surface susceptible de subir des
charges dynamiques dues aux conditions
de fonctionnement ou de l'environnement
(séismes), les boulons d'ancrage doivent
être en acier dur (charge dynamique
de niveau 5).
—
Fig. 4.1
Definition of flat
and level