CHAPTER 2 NORMAL ELECTRICAL SYSTEM
SECTION I. Description and data
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 Chapter 3. 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. Chapter 4 provides detailed information on the two ship service generator (SSG) sets, and Chapter 5
provides similar information on the ship auxiliary generator (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 high
pressure (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
systems. This panel also has indicators for ground detection system. Normal electrical system controls and
indicators are discussed in paragraph 2-10.
Electrical power is distributed through the switchboard distribution panel (Figure 2-1 for Barge 1 and Figure 2-2
for Barges 2 and 3) and these additional distribution panels:
Power panel 1 (440 Vac) (Figure 2-3)
Power panel 2 (440 Vac) (Figure 2-4)
Power panel 3 (120 Vac) (Figure 2-5)
Power panel 4 (440 Vac) (Figure 2-6) (Barge 1)
Deck lighting panel (120 Vac) (Figure 2-7)
Void lighting panel (120 Vac) (Figure 2-8)
Receptacle panel (120 Vac) (Figure 2-9)
Emergency lighting panel (120 Vac) **
Direct current panel (24 Vdc) **
** Discussed in Chapter 3, Emergency electrical system.
Transformers change electrical power from 440 Vac to either 220 Vac or 120 Vac. Three 15 kVA transformers
(in parallel) on switchboard circuit breaker P13 provide 120 Vac power for power panel 3 which provides 120
Vac power distribution for the barge. One 2 kVA transformer on power panel 1 circuit breaker 11 P5 provides
220 Vac for the electric motor that powers the drinking water pressure seL
Mechanisms such as starters, controllers, and switches provide another level for controlling electrical power.
These are discussed in the TM for each individual system.
The final elements are the electrical power consuming devices such as motors, lights, and heaters. These are
discussed in the TM for the system of which they are a part.