UFC 4-150-02
12 May 2003
the pier with a dedicated normal circuit and provisions for switching to a backup circuit.
The Activity is responsible for providing justification for alternate primary feeders and
standby power services required for essential operations. Special electrical primary
systems may be required for certain classes of ships. These specific requirements are
included in SCDB. Provide selective coordination between system equipment
components to ensure minimized downtime of ships systems due to external or internal
electrical system faults. Refer to MIL-HDBK-1004/1, Electrical Engineering, Preliminary
Design Considerations, for a description of the different types of distribution systems.
3-8.2.1
Pier, Wharf, or Drydock Primary Systems. For permanent service,
provide dual primary feeders from the shore primary system to the switching stations or
substations serving the ships' hotel services and industrial loads. For temporary
service, provide dual primary feeders from the shore primary system to strategic
locations that serve portable substations. Conduits, ductbanks, and manholes cast
integrally with the pier structure are preferred for new piers. Conduits on piers may also
be installed in dedicated electrical trenches or in piping trenches that serve other
utilities. To avoid damage to the conductor's insulation, electrical conduits should not
be placed in close proximity to steam piping. Refer to Chapter 2 for general protection
requirements.
3-8.3
Secondary Power Systems. The secondary electrical distribution
system is evolving to higher voltages as the power demand on the ships continues to
increase. It must be designed with the flexibility to serve the various classes and
categories of ships that are anticipated to utilize the facility.
3.8.3.1
Ships Power. Historically, the electrical system providing power for most
ships has been a dedicated 480 volts (nominal), three-phase, 60 Hz, ungrounded
system. This system has been supplied from substations located on piers (or at the
head of the pier for shorter piers), and connected through dedicated receptacles located
at the perimeter of the pier, wharf, or drydock. Currently, 4,160 volts (nominal), three-
phase, three-wires, 60 Hz power is required for later class nuclear aircraft carriers (CVN
68 class and higher). These carriers are sometimes capable of accepting 480-volt
power as well. Future classes of ships (surface combatants and amphibious assault)
are expected to require 4,160 volts (nominal), three-phase, three-wires, 60 Hz power.
Future CVN class ships are expected to require 13,200 volts (nominal), three-phase,
three-wires, 60 Hz power. In general, the pier electrical distribution system must be
designed to limit the fault current contribution from the shore power, at the ship's bus, to
100,000 amps (rms) at 480 volts.
3-8.3.2
Other Ships Power Requirements. When required, provide direct
current (dc) power and 400 Hz power for ships service. These systems must be derived
from portable rectifiers or conversion equipment provided by the Activity. Provide an
electrical power connection system that is supplied from the pier's permanent / industrial
power system rated 277/480 Volts, three-phase, four-wires, grounded, 60 Hz. These
special power systems must not be connected to the ships' dedicated hotel power
service(s).
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