Most of the generators were in the basement. There were bombs planted in the WTC....

The towers were closed and evactuated a few weeks before the attack happend. And all the bomb siffing dogs were taken out the buidling when this happend... Thats when they put the bombs in the buiding.

Also i highly doubt that the WTC buiders were dumb enough to build two 110 story towers with a bunch of explosive objects in it.