I saw this today. Haven't seen anything exactly like it. It's a General Electric panel ( with some Square D breakers ). The service line has one leg attached to a 70 amp breaker, and another leg attached to a parallel bus. The 70 amp breaker has two leads leading to lower areas of the bus. I want to call this a 70 amp service with a split bus panel. I don't understand how the 70 amp breaker would act as a main shutoff.