Glossary

Galvanic isolation

Also Electrical isolation

What is Galvanic isolation?

Two circuits are galvanically isolated when there is no conductive connection between them — energy or signals are transmitted magnetically or optically.

What matters about Galvanic isolation in practice?

On board, the best-known case is the isolation transformer: it transfers shore power energy magnetically, so the on-board system gets its own defined potential. This defuses both the corrosion path and a reverse-polarity shore socket.

Charging converters and bus bridges also work with isolation. In measuring equipment, it is the reason a device can display values from two circuits without connecting them.

Where does galvanic isolation occur on board?

  • Isolation transformer at the shore connection: energy is transferred magnetically, and the pontoon's protective earth is no longer conductively connected to the boat.
  • Chargers with separate windings: the 230-volt side has no conductive connection to the battery.
  • Isolated DC-DC converters: two circuits with different negative potentials are supplied without joining the negative conductors.
  • Optocouplers in measuring and bus devices: signals travel by light, not through copper.

Why does it matter?

Without isolation, equalising currents flow wherever two circuits have different reference potentials. On the water this means corrosion of underwater parts, in measuring equipment distorted readings and on data buses interference. Galvanic isolation removes the cause instead of compensating for the effects.

Is a galvanic isolator the same thing?

No. A galvanic isolator in the protective earth only blocks small DC voltages between boat and pontoon, but lets fault currents through so that protection on shore still works. It is a simple remedy against corrosion. Only the isolation transformer separates completely.

Related terms

All terms from A to Z

Still unclear?

We are happy to explain it for your specific case.

ContactTo the Academy