CHAPTER 3 ELECTRICAL POWER SYSTEMS
Section I. General
3-1 General. Two electrical systems, normal and emergency, are installed onboard The normal electrical system
generates, controls, and distributes all electrical power used onboard to operate the water purification system and its
auxiliary systems. The emergency electrical system supplies 24 Vdc from a battery pack to onboard 24 Vdc equipment
and, through an inverter, converts 24 Vdc to 120 Vac to power emergency lighting and equipment Details are in Section II
thru Section V.
3-1.1 Normal electrical system
3-1.1.1 Normal electric power service consists of any of the following power sources: Electric power generated by either
of the two SSG's, the SAG, or power received from an onshore electric power generating service or from another vessel
through the external power receptacle. In addition, electric power generated onboard the barge can be transmitted
ashore or to another vessel through an external power receptacle.
3-1.1.2 Power from these various sources is controlled and distributed by a master switchboard in ROWPU space
3-1.1.3 Distribution from the switchboard goes either directly to equipment, such as seawater pumps, or to three
intermediate distribution power panels.
3-1.2 Emergency electrical system. This system obtains 24 Vdc power from a battery bank on the deckhouse top for
distribution through a 24 Vdc power panel to operate navigation lights and other equipment. It also supplies power to an
inverter that converts 24 Vdc to 120 Vac for the emergency lighting system.
Section II. Normal electrical system
3-2.1 The normal electrical system provides electrical power for the operation of major and auxiliary systems on the barge
including the emergency system battery charger discussed in Section III. The normal system has six major elements
which are discussed below:
Normal electrical power is generated onboard by one of three diesel-powered generator sets. These generators,
located in voids 4, are normally operated and controlled from a master switchboard in the ROWPU space.
Section V provides detailed information on the two SSG sets, and Section VI provides similar information on the
SAG set. When all generator sets are shut down, a shore-based powerplant or another vessel can be used to
provide electrical power to operate onboard equipment. This outside source is connected to the barge through
electrical cabling to a watertight shore power receptacle on aft weatherdeck portside. These sources provide 440
Vac, 60 Hz, 3 ph electrical power.
Power control and distribution is provided by a main switchboard on the port bulkhead aft of diesel HP pumps in
the ROWPU space. This unit has six panels, three above the grab rail and three below. The three panels above
the grab rail are controls and indicators for the three diesel generators in voids 4. The lower left (as operator
faces the switchboard) distribution panel has two rows of circuit breakers that provide initial normal power
distribution. Two lower right panels contain controls and indicators for the electrical system. This panel also has
indicators for ground detection system. Normal electrical system controls and indicators are discussed in