12 May 2003
Including change 1, 19 January 2007
Cable Lengths. Most ships have to be served from multiple 400A
circuits. Design the electrical system such that cable lengths from the substation to the
outlet assemblies in the parallel circuits are approximately equal (within 10 percent).
Combined Equipment. Electrical substations and outlets may be
consolidated in an integral package, with the receptacles placed in the side (or sides) of
the substation enclosure. These consolidated outlet assemblies may be spaced as
necessary along the pier or drydock perimeter. See Figure 3-18, cases III and IV.
Outlet Assemblies for Portable Equipment. When supplying ships
loads from portable substations, locate primary outlet assemblies in the same manner
as required for regular outlet assemblies. Primary outlet assemblies, provided for
temporary services that supplement permanent substations, should be placed in the
vicinity of their intended use. Coordinate these locations with the Activity and the
cognizant NAVFAC EFD/EFA OR USACE DISTRICT.
Distribution System Equipment and Materials. Equipment and
materials selected for waterfront electrical systems must be coordinated with the
cognizant NAVFAC EFD/EFA OR USACE DISTRICT and the standards and
preferences of the Activity. Since significant technical information for many of the
distribution system components is available in the Unified Facilities Guide Specifications
(UFGS ) Sections 16360, Secondary Unit Substations, 16341 SF6 Insulated Pad-
mounted Switchgear and 16442 Switchboards and Switchgear, the nomenclature and
requirements for the equipment must be thoroughly coordinated in the project
documentation (plans and specifications).
Fixed Substations for 480 Volts Service. There are several methods for
providing substations for permanent 480 volts services on piers. Based on the overall
system design, the substation should contain primary, secondary, auxiliary, and
transformer sections. See Appendix D. The primary section would either contain the
primary overcurrent protection features, a disconnect switch, and a service circuit
selector switch if the system includes multiple primary circuits, or it would be limited to
the primary circuit terminations if separate pad-mounted primary switchgear is used.
There must be separate 480 volts secondary unit substations designated for the ships
hotel loads and for the other pier loads including industrial power (if required). The main
transformers should be of the liquid-cooled type, standard three-phase, 480 volts, with
four full-capacity, 2-1/2-percent taps, two above and two below the nominal primary
voltage rating unless actual operational conditions require other tap settings. Maximum
transformer rating should be 4000 kVA. Substations, including transformers should be
stainless steel with a paint coating system in compliance with ANSI C57.12.29. If
specific operational conditions require parallel operation with the shipboard generators,
coordinate with the cognizant EFA / EFD and NAVSEA to determine the additional
features that must be added to the equipment. In these cases, the shipboard generator
and other equipment ratings are available upon request from NAVSEA.
Shore Power Circuit Breakers. The equipment should provide 480 volts
(nominal), three-phase, 60 Hz power, as defined in NEMA C84.1, Voltage Ratings for