The reserve sources of energy need to supply independent MF and HF radio installations at the same time.

At all times while the vessel is at sea, a sufficient supply of electrical energy to operate the radio installations and charge any batteries which may be part of the reserve source of energy is required.

An uninterruptible power supply or other means of ensuring a continuous supply of electrical power to all GMDSS equipment that could be affected by normal variations and interruptions of ship's power is required.

If a vessel’s position is constantly required for the proper performance of a GMDSS station, provisions must be made to ensure position information is uninterrupted if the ship’s source of main or emergency energy fails.