I've put in dozens of electrical services, but have not run into this before. Is it safe or legal to hook a 30-60 amp generator plug in (9400 watt start & 7500 watt running), on the bottom side of the 200 amp service disconnect, with a double lug, and the when they have a power failure, throw the switch to off,(lesson the chance of back feeding onto the power companies lines) turn on their generator and feed their 200 amp power panel with the main in the on position. Of course they would switch off non needed breakers like the furnace, AC, stove etc. Will their 200 amp main breaker handle essentially low voltage flowing through it? They are trying to avoid a transfer switch and drilling more holes into their outside walls.