This part of IEC 61892 contains provisions for electrical equipment in mobile and fixed offshore units including pipeline, pumping or 'pigging' stations, compressor stations and exposed location single buoy moorings, used in the offshore petroleum industry for drilling, processing and for storage purposes. This edition includes the following significant technical changes with respect to the previous edition: a) the requirement to d.c. generators has been deleted; b) detailed requirements to testing of machines have been deleted. Reference is made to the IEC 60034 series; c) requirement to switchgear and controlgear has been rewritten, based on updated IEC 60439 and the IEC 62271 series; d) requirement to Control and instrumentation has been rewritten, based on updated IEC 60092 504.