Galvanic Isolator primer
If your boat is made of metal AND you connect to a shore supply, there is a serious risk of Galvanic Currents, Stray electrical currents, and Earth Leakage causing enormous damage to your vessel. A galvanic isolator can prevent this.
When dissimilar metals are immersed in water, they act as a battery, and when the circuit is completed, an electrical current will flow. We call these currents “Corrosion Currents”. More about that later. What you need to know is this…
“When Galvanic Current flows, it takes metal from the hull of your boat and deposits it on the bank side – you don’t want that”
The current that flows can be quite small, but over a period of months, your boat could shed many many kilograms of its hull, leading to pitting, and even holing.
Believe me when I tell you that this is no fairy tale – my own hull has lost around half a tonne in weight through corrosion that could have been prevented for just a few pounds with a simple galvanic isolator (sometimes known as a Zinc Saver).
In fact, there are TWO types of corrosion current that are often mistaken for the same thing.
And it gets worse still!
As the hull starts to corrode, pits begin to form in it’s surface and because the pits have a larger surface area than unpitted metal, the corrosion speeds up. Before long, the anodes will have been dissolved away, and your boat is left entirely at the mercy of corrosion – and it’s a boat-killer.
Fortunately, the problem is not difficult (or expensive) to resolve. What you need to achieve is to SAFELY break the electrical earth that connects your boat to the shore supply. Note, I say SAFELY.
You achieve this with a “Galvanic Isolator”, a simple electronic device that blocks corrosion currents from flowing, while allowing the safety electrical earth to remain intact. There are two types of galvanic isolators:
A Plug in galvanic isolator that simply connects in-line with your mains connecting cable.
- A Wire in galvanic isolator which is part of your boat’s internal electrical wiring