Division 2.2 An emergency electrical power source must be provided.

Except in open vessels, it must be located outside the engine room and must, in all cases, be so arranged as to ensure in the event of fire or other failure of the main electrical installation, simultaneous functioning for at least three hours of:

• the internal communication system, fire detectors and emergency signals,

• the navigation lights and emergency lighting,

• the radio installation,

• the emergency electrical fire pump where present.

If the emergency electrical power source is an accumulator battery and the main electrical power source fails, the accumulator battery must be automatically connected to the emergency electrical switchboard and supply power for an uninterrupted period of three hours to the systems referred to in the first, second and third indents of the second subparagraph.

The main electrical switchboard and the emergency switchboard must, to the extent possible, be installed in such a way that they cannot be exposed simultaneously to water or fire.