GE Industrial Solutions Power Equipment Buildings User Manual

GE Electrical Distribution

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General Electric Company
41 Woodford Avenue, Plainville, CT 06062
860 747-7111

and Control

GE EQUIPMENT CENTERS

APPLICATION CONSIDERATIONS

Introduction

For many years the petro/chemical industry has utilized equipment center’s to house their electrical distribution
equipment. Many industrials and utilities are now utilizing equipment center's for their equipment. The purpose of
this paper is to define equipment center's and compare to present technology for outdoor electrical equipment.

Definition

An Equipment Center is a prefabricated, modular electrical/instrument enclosure. As a self-contained unit, it is a
completely assembled building manufactured in a factory enviornment. Typical equipment enclosed by an equipment
center is {low & medium voltage switchgear, motor controllers}, Relay Panels, RTU'S, instrument control panels,
DCS systems, Heat Trace Panels, UPS systems, Battery Systems and SCADA systems. The equipment center can also
serve as an outdoor enclosure for high voltage switchgear when Gas Insulated Switchgear (GIS) equipment is utilized.

An equipment center is designed and manufactured in accordance with a number of rigorous industry standards as
outlined below. Additionally, an equipment center must comply with local building codes. The most common
designs are self-framing interlocking wall and roof panels attached to structural steel base.

Table 1

ASCE 7-88 Minimum Design Loads for Buildings and Other Structures

(ANSI A58.1)

NEC (NFPA-70) National Electric Code

AWS DI.1 American Welding Society - Structural Welding Code

ASTM A-6 General Requirements for Rolled Steel Plates, Shapes, Sheet Piling

and Bars for Structural Support

ASTM A-36 Specification for Structural Steel

AISC Manual of Steel Construction - Allowable Stress Design

UBC Uniform Building Code

Electrical Equipment Centers

Application Considerations

Page 1

Wall System

Wall panels are typically 18 gauge painted galvanized steel that is formed to provide an interlocking system.
Interlocking 3" exterior wall panels are typically on 16" centers and provide 100 MPH allowable wind loading. Higher
wind load ratings are provided as required. Interior wall liners and insulation can also be provided.

Resistance to Environments

The interlocking panel design inherently provides a barrier against water entering the equipment Center by providing
two 90' bends at seams between the exterior and interior of the equipment center. Additional weather-proofing is also
provided to ensure enclosure integrity. After assembly of the wall system, all seams are sealed with industrial grade
silicone sealant. Roof sealing putty is used at all wall-to-roof joints and at joints on peaked-roof enclosures. All roof
panels are also individually sealed with silicone sealant.

The paint system consist of surface preparation, primer, underside coatings, finish paint and sealant. The finish coat is
typically epoxy-based, to provide outstanding resistance to chemicals, moisture and abrasion; The flexible coating is
highly resistant to the deteriorating effects of many acids, alkalis, solvents, greases, oils and other active chemicals.

The resulting enclosure can be designed for extreme ambient temperature and humidity environments, ranging from

-40'C to +50'C, while allowing the use of lower cost indoor types of switchgear and electronic equipment. For special
environments, the equipment center can also be fabricated from aluminum, stainless steel or fiber glass.

Grounding System

The equipment center is furnished complete with suitable factory installed grounding connections which bond all
electrical equipment enclosure frames/ground buses to the building frame. Two (2) 4-hole ground pads are located at
opposite corners of the exterior of the building. Separate "quiet" or isolated instrument ground bus can also be
provided.

Other Construction Features

Typically, equipment center's are provided with interior and exterior lighting, heating, ventilation and duplex
receptacles. An equipment center can also be provided with air conditioning, humidity control, and
pressurization/purge systems (NFPA 496). Additionally, most features available in a site built building are available in
an equipment center; including offices, bathrooms, communications room, battery rooms, etc.

Applications

Application of an Equipment Center is usually compared with conventional outdoor electrical/instrument enclosures
such, as concrete block buildings and sheltered-aisle switchgear, Evaluation is centered around the issues of
effectiveness for the application, initial installation costs, and total life cycle costs. Specific construction and
procurement factors provide the basis for a more detailed technical and commercial comparison of alternatives.

Electrical Equipment Centers

Application Considerations

Page 2

Equipment Center vs. Conventional Building

Equipment Centers are primarily used in applications that have traditionally favored electrical rooms constructed at the
site utilizing conventional construction techniques. The below table describes the advantages of an equipment center
with the most common alternative, a concrete block building.

Table 2

Equipment Center Conventional Building

Major Electrical Equipment
Sourcing

Design Engineering

Construction

Foundation

Base

No difference No difference

One manufacture is responsible
for all equipment purchasing

Separate solicitation, analysis
(and often) sourcing of
switchgear, building, battery
systems, bus duct, etc.

Complete package designed and
engineered by one manufacturer

Variety of materials, depending

Purchaser must design and
engineer

Typically, concrete block
on application environment and
structural requirements including
galvanized steel, stainless steel,
and aluminum

Minimum foundation i.e.,
curb type or pier type

Requires full slab foundation with

relatively large stem walls and

footing

Self-supporting, allowing all
equipment to be factory leveled
before shipment

Purchaser provides channel base

and grouting for leveling all

equipment

Internal wiring

Main bus interconnections

Bus duct from transformers

Grounding system

Factory wired complete with
wiring schematics

Job-site interconnection of

control wiring as well as major

equipment

Coordinated by equipment center
supplier.

Purchaser coordinates the match

up of main buses for different

types of equipment

Checked for ease of assembly Purchaser coordinates and

assembles bus to switchgear in

field for first time

Integral to equipment center Must be planned and built into

foundation

Equipment Center Conventional Building

Electrical Equipment Centers

Application Considerations

Page 3