Figure 3-1.--Typical power distribution system found in a large combatant ship.

readiness: class 1, class 2, class 3, and class 4.

colored black on surface ships, and the symbol for

Readiness classification only switchboard plates is

submarines is a rectangle.

indicated by color on surface ships and by a specific

symbol on submarines.

Class 3

Class 1

Class 3 IC systems are systems that, together with

class 1 and class 2 systems, are essential to complete

Class 1 IC systems are systems that are essential

interior control and battle circuits. Class 3 systems are

to the safety of the ship and ship personnel. Class 1 IC

energized during condition watches and operations.

systems are energized at all times. The switchboard

plate is colored yellow on surface ships, and the

The switchboard plate is colored red on surface ships,

symbol for submarines is a rectangle within a

and the symbol for submarines is a circle.

hexagon.

Class 4

Class 2

Class 4 IC systems are convenience circuits.

Class 2 IC systems are systems that, together with

These circuits are energized only when they are

class 1 systems, are essential to ship control. Class 2

required. The switchboard plate is colored white on

systems are energized when the ship is preparing to

surface ships, and the symbol for submarines is a

get underway, standing by, underway, and anchoring,

and until the ship is secured. The switchboard plate is

triangle.

Figure 3-1.--Typical power distribution system found in a large combatant ship.

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