Designing the Electrical System

Utility Coordination:

• The consultant must work with the serving utility to coordinate service entrance arrangements, and the utility needs must be noted on the project designs. This includes any utility that makes faults available.
• Drawings must state if utility expenses are to be included in the proposal or if they are to be covered via a separate contract. The state would rather pay for utility extensions through a separate contract with the utility. The consultant is responsible for coordinating the extension with the utility, obtaining the extension cost, and informing the DFD project manager of the cost.
• The electrical design should include a short circuit and coordination research to find overcurrent protection devices that will provide a selectively coordinated system for the building's emergency systems. A preliminary arch flash hazard analysis should be included in the design to identify potential arc flash risks and create mitigation methods.
• The commercial electrical power service entry position should be chosen simultaneously as the conceptual design. The concept design should include space planning papers and requirements for equipment provided by utility companies.
• The consultant must consider any utility or municipal easements on State land and State easements on municipal property. The consultant will meet with the utility or municipality to determine the requirements for new and current utility routing and rerouting on municipal property. When new easements on State land are desired, consult with the appropriate agency.

Site Work:

• It may be required to have many services in the event of huge buildings or buildings with large footprints. Medium voltage power distribution may be required in large office buildings and campus settings. Medium voltage, up to 15 kV, should be used for primary power distribution to substations if available.
• For regions where electrical installations will be excavated, the consultant must identify known subsurface utilities on the electrical project designs. Consultants must be aware of large underground utilities, such as steam tunnels, that will impact two underground electrical installations and design accordingly.
• In the case of improvements at existing facilities, the consultant will work with DFD and the agency to locate agency-owned utilities. The agency is in charge of locating utilities.
• Natural gas fuel with propane backup should be used in emergency generators rated 50KW or less. Fuel tanks are not permitted to be buried. The Owner is responsible for providing propane tanks. Diesel emergency generators with a capacity of more than 50 kilowatts are required. Wherever practical, incorporate an 8-hour operation fuel tank within the unit's base.

Coordination with other Divisions:

• All electrical systems must be coordinated with the architectural and mechanical drawings. Electrical services to HVAC and plumbing equipment and particular architectural equipment should be considered. Remark the electrical drawings if electrical work is shown on the architectural or mechanical drawings.
• To identify the enclosure and pathway requirements for telecom systems, the Architect/Engineer will work with the client agency. The scope of services varies by project, but it often comprises infrastructure design as a minimum and full design and specification of the telecom system.
• The architectural and electrical designs must be integrated, so that appropriate space is available to install and maintain all equipment. No electrical equipment prone to failure must be installed in any area where replacement would necessitate excavation or building alteration.
• Examine the ceiling architecture in electrical and telecommunications rooms. Ceilings with pans and beams should be avoided. If architectural designs show this, inform the architect that DFD prefers flat ceilings in these rooms.
• Include any smoke partitions and fire-rated walls on the electrical plans, or include a notation directing readers to the architectural designs for identification.
• The electrical designs show all egress route lines for egress illumination calculation and submittal criteria.
• For utility billing purposes, all electrical installations are normally metered at the transformer for KWH/KWD. Metering from the switchgear should be the first focus. All pad-mounted transformer metering equipment, including the meter, meter base, current transformers, potential transformers, wiring, and terminations, must be supplied and installed by the contractor.
• Current transformers should be dual rated to accommodate a greater rating for future extra loads. Two duplex grounded convenience receptacles should be installed near the meter powered by the emergency power supply. The meter should be factory wired and flush-fitted with high interrupting fuse protection in free-standing switchgear. HIC fuses should be used to safeguard potential tap locations.

Service and System Continuity

• Electrical outages should be planned when they will cause the least amount of disruption to typical institutional schedules and company operations. Before the final drawings/specification review, the consultant is expected to address any service interruptions with the user agency and building occupants to decide the best way to make the electrical adjustments.
• When power must be turned off in a specific region to enable project work, a temporary generator should be considered to vital power loads. Indicate on the drawings and in the requirements if necessary.
• All generators must be powered by diesel fuel stored in a belly tank. Buried fuel tanks are unacceptably dangerous. Fuel tanks must withstand full load for at least 8 hours. Lab buildings must have a minimum fuel capacity of 24 hours at full load.

Raceways and Conduit

• Except for low voltage control or signal cables routed above accessible ceilings, all wiring is expected to be arranged in metallic or non-metallic raceway systems.
• Unless mechanical rooms or remodeling projects require existing wall construction that does not allow for open conduits and boxes, conduits must be routed discreetly. Any sites where the conduit will be run exposed must be noted on the drawings by the consultant. All channel-type surface raceway locations must be identified on the designs.
• The underground duct bank and manhole system serve all new facilities, facility additions, and renovations requiring new or modified primary electric system service. All-electric facilities included in the project, such as duct banks, manholes, cable, transformers, switchgear, lighting arrestors, terminations, and associated materials, must be included in the project budget.
• Designers must describe the location of the power and phone service sources and the installation of phone and power conduit to the unit. Both services must be performed by the contractor and will not be handled by the owner at a later date.