Wow, that is amazing. The manual states to ground it so the GFIs work properly? Ground has absolutely nothing to do with the operation of a GFI. A GFI measures the amperage of the neutral and the amperage of the hot wires. If they are identical then it allows the current to keep on moving. If there is a leak and therefore a mismatch of around 5 milliamps then it trips the circuit in less than 1/30th of a second. That leaked current is going to ground, but there is no ground wire in the circuit. The leaked current is going to ground either through an alternate path, such as water or a human being. The beauty of a GFI is the speed at which it detects the ground fault and trips the breaker. The fellow who invented the GFI gave a public demonstration to prove the worth of the GFI by holding a radio that was plugged into a GFI outlet and jumped into a bathtub full of water. He lived and every new building constructed since then is protected by GFIs.