EquipmentCenters vs. Conventional Buildings

A Metal Systems' Equipment Center (EC) is a prefabricated, modular electrical/instrument enclosure solution. As a self-contained unit, it is a completely assembled structure manufactured entirely at the factory with a self supporting base frame and floor. Typical equipment enclosed by the EC includes switchgear, motor control centers, relay panels, RTU's, instrument control panels, DCS systems, heat trace panels, UPS systems, variable speed drives, battery / DC systems and SCADA systems.

Table.1 A comparison of EC's and conventional site built buildings.
Aspect	Equipment Center	Conventional Site Built Building
Tax, Depreciation & Commercial Issues	Taxed and depreciated as equipment over 5 - 7 years, vs. Real Estate over 29 years.	Treated as real estate improvement leading to higher tax schedule, much longer depreciation, building permits, progress inspection, bonding & insurance.
Major Electrical Equipment	Pre-installed, wired and tested at factory before shipment	Stored, handled, installed, wired and tested on site
Sourcing	EC manufacturer is responsible for all equipment inside EC.	Separate solicitation, analysis (and often) sourcing of switchgear, building, battery systems, bus duct, etc.
Design Engineering	Complete package designed and engineered by EC manufacturer.	Purchaser, or engaged third party, must design and engineer.
Future Portability	Disconnect line and load cables and the EC is ready to move	Not feasible
Future Expansion	EC may be constructed with removable ends for quick and easy future expansion	Extremely cumbersome, especially with block wall construction
Foundation	Minimum foundation - piers or ring wall.	Requires full slab foundation with relatively large stem walls and footings.
Construction	Variety of materials including painted galvanized steel, stainless steel, and aluminum	Typically, concrete block.
Base	Self-supporting, allowing all equipment to be factory installed and leveled before shipment.	Purchaser provides channel base and grouting for leveling all equipment on site.
Internal Wiring	Factory wired complete with wiring schematics.	Job-site interconnection of control wiring as well as major equipment.
Main Bus	Coordinated by EC manufacturer.	Purchaser coordinates the match up of main buses for different types of equipment.
Bus Duct from Transformers	Checked for ease of assembly.	Purchaser coordinates and assembles bus to switchgear in field for first time.
Grounding System	Integral to EC.	Must be planned and built into foundation.
External Connections	Easily adaptable to overhead or underground conduit systems.	Slab floor mandates detailed and exact conduit location; changes are difficult.
Testing	EC is factory tested; customer can complete many pre-energization tests before installation. Witness testing at one location.	Each type of equipment is tested at different factories. Witness testing requires more time and travel.
Changes	Changes can be made after functional testing and inspection in controlled factory environment.	Requires coordination between various trades, often after initial construction is complete.
Receiving, Handling, & Storage	Arrives in single shipment, usually unloaded in one hour, can be stored indefinitely as integral unit, inherently protected against elements.	Multiple component receiving often involves redundant handling for storage, trucking to intermediate locations, and protection during storage from pilferage or other loss, or lost time due to weather.
Electrical Load Cables	Place the EC near the process being controlled for minimal Load cable runs	Load cables may have to run excessively long lengths from the conventional building to the process being controlled
Installation	Involves minimum number of crafts.	Requires many crafts; i.e., carpenters, ironworkers, cement finishers, bricklayers, electricians-all with foremen and helpers.
Schedule	Have the completed EC delivered the day it fits in your critical path	Requires months of multiple trades and on site coordination