0EddieBones 9 years ago ReplyUpvoteDifferent metals have more or less electrons in their atoms. When two different metals contact, the difference in electrons create difference of potential (galvonic reaction), This difference of potential causes corrosion (corrosion). The idea is to connect a sacrificial anode and apply a voltage of opposite polarity causing a cancellation of the galvonic reaction. If you can cancel the voltage difference you stop the corrosion. If some of the voltage remains the anode will be used up instead of the base metal your trying to protect.. Yes it works. You don't need to be grounded to the Earth, ground is a reference.