Main switchboard distributes and control the power to switches and control various equipment on vessels. Its main function includes controlling and monitoring single or parallel operation of generator sets; switching on/off power distributors for each electrical equipments.

Emergency switchboard is used in emergency. It should be as close to emergency power as possible. When the main power comes from the emergency generator, the emergency switchboard should be with the emergency power in the same site unless it could interfere with the operation of the emergency switchboard.