I have seen a similar scheme on some older poles around here, although I'm pretty sure they are not isolated. If multiple transformers are running on the same primary, and their secondaries run to a common bus, the load should be evenly distributed, shouldn't it?
Last Summer, Con Ed of NYC had some spectacular cascading failures in areas where they had multiple transformers feeding a common bus. Seems some of the transformers failed, and the transformers still alive had more loading, and the bus wires started literally burning up in places. A lot of underground wiring had to be replaced, and some customers had to be fed with generators Con Ed set up locally on the street. It was a mess, and the city government was rather unhappy about it.
