There are also “boosting” Isolation
Transformers like the Charles Iso-Boost
Automatic Marine Isolation and Boosting
Transformer. Where long dock runs can
cause voltage drops or fluctuations in the
shore power supply, a “boosting” unit provides the benefits of an Isolation
Transformer, plus automatically "boosts"
low or fluctuating voltages.
the current to find a path to earth.
Remember, electricity must have a complete circular path. With shore power, the
shore power system is connected to earth.
The path is from the power pedestal,
through the shore power cord, into the
faulty system, out the prop (for example)
and completes the route back to earth
through the water that may only be a few
feet deep in the marina.
Even with your generator running, a
faulty system with the metal prop in the
water as before, there is only one path to
earth, so there is not a complete round
trip. The swimmer is in no danger here
(at least until the boat reconnects to
I’m not trying to scare you into giving
up boating! But my goal is to absolutely
convince you to never swim where there
is shore power.
Next, there are a few easy steps you
should take to ensure everyone’s safety.
The American Boat and Yacht Council
(ABYC) who sets most of the construction and safety standards for boat
builders and repairers, recommends any
vessel with shore power connections
should have an isolation transformer.
Isolation transformers are available
from Charles Industries, Mastervolt,
Marinco and others. With an isolation
transformer on your boat, the electrical
malfunction no longer creates an electro-
cution hazard in the water.