I have a question to this statment by Scott35: "For AC, there is no fixed Polarity, so it is safe to say that current flows in BOTH directions."

For 120 Volt circuits it seems to me that the current has only one direction. Although the AC generator creates a nominal voltage of +120 to -120, I only see current flow when the voltage is positive. Therefore, when the voltage is negative, there is a lull in current flow.

If you can imagine a 120/240 Volt transformer with a center-tap to ground. As the AC generator cycles, the direction of the current changes from A leg to B leg. However, Whether the current is flowing from A or B, the potiential to ground will never be overcome, therefore it will always flow through the neutral to ground.

I have to appologize if that isn't entirely clear, I'm still pretty new to electricity but desire to know as much as I can.

Thanks,
Byron