GE Industrial Solutions Power Equipment Buildings - Manual (Page 6)

Electrical Equipment Centers
Application Considerations
Page 6
Most major switchgear suppliers offer a line of sheltered aisle in single-row or double row arrangements that typically
comply with NEMA 3R requirements for outdoor installation. Single-row installations consist of a line-up of outdoor
switchgear adjacent to a weatherproof walk-in aisle. The overall design provides weather protection and good
economy of space, but is limited in application flexibility and room of auxiliary equipment. The below table provides
a more detailed comparison of equipment center construction and application as an alternative to NEMA 3R Sheltered
Aisle Switchgear enclosures.
Table 3
Equipment Center Sheltered Aisle Switchgear
Major electrical
Equipment No Difference No Difference
Sourcing One Manufacturer is responsible;
enclosure is flexible and can
accommodate various equipment Separate enclosure must be
sourced for each type of electrical
equipment
Design and Engineering Complete package designed and
engineered by one manufacturer Purchaser must design and
engineer
Foundation Minimum foundation, i.e.,
curb type or pier type Usually requires full slab
foundation with relatively large
stem walls and footings
Base Self-supporting, allowing all
equipment to be factory leveled
before shipment Purchaser provides channel base
and grouting for leveling all
equipment
Internal wiring Factory wired complete with
wiring schematics Job-site interconnection of
control wiring as well as major
equipment
External connections Easily adaptable to overhead or
underground conduit systems Slab floor mandates detailed and
exact conduit location; changes
are difficult
Testing Unit is completely factory tested;
customer can complete many
pre-energization tests before
installation
Receiving, Handling
& Storage Arrives in single shipment,
usually unloaded in one hour; can
be stored indefinitely as integral
unit, inherently
Equipment Center Purchaser must provide for
receiving and storage multiple
units made at different times by
different suppliers.
Sheltered Isle Switchgear
Receiving, Handling
and Storage (Cont.) Often times involves redundant
handling for storage, trucking to