How does a Galvanic Isolator work?

A Galvanic Isolator works by blocking the small electrical currents that can flow along your boat’s electric hook up cable, sometimes known the shore line.

Of course, the electric hook up cable is intended to carry electrical current, and depending on the part of the world you’re in, it’s typically 230 or 120 Volts Alternating Current, or “AC”. AC current does not damage your boat.

However, small Direct Currents, “DC” can also flow in the hook up cable, and these currents, known as Galvanic Currents are unwanted, and they definitely can cause severe damage to your boat’s metal hull, propeller and stern gear. 

Galvanic currents are caused by the chemical action between the boat and it’s environment. All boats have it, and it’s quite a complex chemical reaction - exactly the same reaction that batteries rely on to work. In the case of a boat, the voltages are quite small - nowhere near enough to hurt you - but MORE than enough to severely damage a boat in a remarkably short time.

A Galvanic isolator, sometimes known as a zinc saver, is a relatively simple electronic device that completely blocks Galvanic currents, whilst letting the AC - the current you want - flow freely.

ALL boats that are connected to an electric hook up have Galvanic currents to some degree. It’s nothing that some boats have, and others haven’t. Fitting sacrificial anodes to the boat can give some protection to the hull etc., but the Galvanic currents also eat away at the anodes. And when they’re gone, the hull’s next.

Speaking of sacrificial anodes… most boats don’t have nearly enough anodes fitted to adequately protect the hull, so it’s worth taking advice before just fitting a couple of anodes. 

The great news is that as well as protecting your boats hull etc., a Galvanic isolator will also make your anodes last much longer - up to 5 times as long.

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