This standard specifies the classification, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage requirements for marine power and lighting transformers. This standard applies to equipment installed on ships with voltages below 500V and frequencies of 50 Hz and 60 Hz. Dry-type self-cooling power, lighting and isolation transformers with single-phase capacity of 0.5 to 100 kVA and three-phase capacity of 3 to 100 kVA.