My charging source will sometimes be 120 VAC, and sometimes 240 VAC. I plan to have a step down transformer on the circuit between the source and the multiplus for those occasions when the source is 240 VAC. On the occasions when the transformer is not needed because the source is 120 VAC, is there a convenient way to wire the circuit using a switch which will open an alternate path for the current which avoids the transformer and heads straight to the multiplus? Frankly, I am certain there is a way to do this, but since I am not an electrical engineer, I am not sure what parts I need or how to physically wire the circuit. It would be great if it could be set up so that all I would need to do is flip a switch when I know that I am going to be receiving 120 VAC. Thanks!