Criteria for selection of distribution transformer as per IS:10028 (part-I) 1985: 1) Total connected load. 2) Load Diversity factor. 3) Expected daily load curve. 4) Type of loads: (1 phase, 3 phase, 3 ph-4 wire system required) 5) Constant Losses. 6) Availability of space for transformer erection (indoor /outdoor). 7) A distance of loads from the transformer substation. 8) Times of low loads and maximum loads. 9) Future expansion plans or trends or forecasting. 10) Ambient conditions for deciding insulation class. 11) Tap changing requirement.