Download Electrical Narrative

Introduction
Electrical systems will be provided for a new Company Operations Facility at Fort
Huachuca, Arizona, including power, lighting and special systems for a fully operational
facility. Elements of the various electrical systems will meet all requirements described
in the RFP. General electrical design will comply with the NEC, NFPA and other
applicable codes, UFC and standards.
Electrical Service
The primary service and pad mounted transformer will be provided by Sulphur Springs
Valley Electric Cooperative (SSVEC). The contractor will provide the concrete pad and
substructure. From the secondary of the pad mounted transformer, service entrance
conductors will be provided through underground 4” PVC, conduit into the main
electrical room. The pad mounted transformer will provide 480Y/277V power to an
interior main 400 amp service entrance panel. The service entrance conductors will
terminate on a service entrance main distribution panel board (MDP).
Power Distribution
The MDP will consist of a solidly grounded neutral 480Y/277V, three-phase, four wire
panel board with a main copper bus, 100% rated main circuit breaker and grounding bus.
Step down 208Y/120V secondary transformers will provide secondary distribution to
branch circuit panel boards. Wall receptacles will be provided in quantity and locations
described in the RFP. GFI type duplex receptacles will be provided in restrooms, break
rooms and other areas as per NEC 70.
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Distribution panels will be provided with copper phase, neutral, and ground
busses and balanced within ±10% of the average load. Panel boards feeding nonlinear loads will have a 200% neutral bus to avoid overheating.
Transformers feeding non-linear loads will be K-rated to protect from harmonic
currents.
Branch circuit conductors will be copper, sized for maximum 3% voltage drop
and installed in a conduit with grounding bushings at all conduit terminations.
EMT conduit will be used for concealed installations. Rigid steel conduit will be
used where conduits may be subject to physical damage.
GFI receptacles will be wired so loss of power on one receptacle does not affect
downstream receptacles.
Service will be sized for 25% spare capacity to accommodate for future
expansion.
Transient Voltage Surge Suppression (TVSS)
A UL 1449 listed and labeled TVSS device will be installed adjacent to the main
distribution panel to provide a path to ground for an electrical surge and to limit the
magnitude of transient surges in the building electrical system.
Grounding
Power system grounding will be provided in compliance with Article 250 of the NEC
(NFPA 70) and UL 467. A complete interconnected counterpoise system will be
provided around the building. Major elements that will be grounded to this system
include the transformer enclosure, lightning protection down conductors, the service
entrance panel ground bus, communication grounding bus, building steel and primary
metallic water service piping. All connections to the counterpoise system will be made
with exothermic welds. The maximum impedance of this system will be 10Ω.
Lightning Protection
A complete lightning protection system will be provided conforming to NFPA 780. All
connections will be exothermically welded and terminated into the building grounding
loop.
Interior Lighting
Lighting will be designed per IESNA standards and to the requirements of the RFP. The
primary lamp source will be fluorescent utilizing energy saving electronic ballasts with a
lamp color temperature of 4100K and Color Rendering Index (CRI) of 85 or higher. Ballast
shall be energy saving high frequency electronic with total harmonic distortion less than
10%. The use of this type of ballast will result in overall energy savings throughout its life
cycle. Dimming ballast will have the capability of dimming to 1%. All fixtures shall be of
heavy commercial grade to ensure long life, quality lighting and ease of maintenance.
Direct/Indirect fixture types will be used to limit glare for improved viewing of video
display screens and be controlled with commercial grade area switching, occupancy
sensor or dimmer as required. Task lighting will be provided at every workstation to
increase occupant lighting level controllability. The use of occupancy sensors will
reduce the overall energy consumption of the building. Illumination levels will be as
recommended by the IESNA and providing levels required for LEED.
Exterior Lighting
Exterior building mounted lighting fixtures shall be sharp cut-off type and shall be
controlled by photocell. Contractor will provide pole foundations for lights and poles
supplied by SSVEC.
Emergency and Egress Lighting
Where required, egress lighting will be provided with general luminaries connected to the
lighting circuit ahead of the local switching. Emergency lighting will be provided in the
combination form of integral emergency battery ballasts in the luminaries and Emergency
Battery Units along the path of egress. Exit signs will be internally illuminated LED with
integral battery backup. The emergency lighting at the exterior egress doors shall be
provided to illuminate the path of egress outside of the exit. Emergency lighting will be in
accordance with NFPA 101.
Security Systems
Conduit, power and control wiring to support the ICIDS system in the Arms room will be
provided. A one inch exposed rigid steel conduit will be run from the Arms room to the central
telecom room.
Fire Alarm and Mass Notification System
A combined Fire Alarm Mass Notification System will be installed in the building
conforming to UFC 3-600-01, UFC 04-021-01 and NFPA 72. The system will be looped,
Class A, addressable, intelligent, supervised with a combined Fire Alarm Control Panel and
Autonomous Control Unit located in the main electrical room. Photoelectric duct detectors
will be provided as in Air Handling Units when required by code. In accordance with NFPA
72 and the ADA, combination audible/visual notification devices will be installed throughout
the facility to provide “public mode” notification of an alarm. Visual devices will be
synchronized when more than one device is located in a common field of view. Tamper and
flow switches will be provided on the sprinkler system at the fire risers, valve pits and at the
zone valves. The system will be capable of providing Mass Notification functions according
to UFC 04-021-01, including live voice messaging, telephone and wireless input, and
playback of prerecorded messages. Weatherproof exterior speakers will be provided at
exterior gathering locations and entrances to the buildings. Speakers will be shared while
separate strobes will be provided for notification of Fire Alarm (white) or Mass Notification
(amber) alarms. Communication capability will be provided in the form of a Monaco radio
transmitter compatible with the installation system.