The majority of the systems covered here operate at a nominal voltage of 24 y dc and, although it is not necessary for each of the above systems to have separate battery and battery charger systems, the grouping criteria require more detailed discussion. These are covered in chapter 5, as is the need to provide dual chargers and batteries for certain vital systems. In addition to the above systems there are, of course, switchgear tripping/closing supplied and engine start batteries which are dedicated to the equipment they supply. In the case of engines which drive fire pumps, duplicate charges and batteries are also required. This subject is discussed in chapter 4. This work is intended to be of interest to both technical readers and to general readers. It covers electrical engineering in offshore situations; much of the information offered has been gained in the North Sea. Some topics covered are offshore power requirements, generator selection, process drivers and starting requirements, control and monitoring systems and cabling and equipment installation.