Specifications
C.
Polarity
indicator
If
the dockside power source is incorrectly wired and
has the polarity reversed, the MAIN circuit breaker will
sense the voltage difference between the neutral and
ground terminal blocks, this will trip the MAIN breaker.
The reversed polarity indicator will remain illuminated
even though the breaker has tripped.
E - 9 ELECTRICAL SYSTEM MAINTENANCE
Periodically, inspect all wiring for nicks, chaffing, em-
brittlement, improper support, etc. Examine the
shore power cord closely for insulation cracks and
corrosion
in
the electrical devices. Spraying the recep-
tacles and electrical connections with
an
electrical
connection cleaner, such
as
"LPS"or"CRC,"will reduce
corrosion and improve electrical continuity.
The entire 120 (220) volt circuitry, especially the shore
power cord, should be seasonally tested for proper
continuity by
an
experienced marine electrician. This
will help detect any short, open wire,
or
ground fault.
Also, check the polarity indicator system for proper
operation.
E·
10 ELECTROLYSIS & CORROSION
Two types of electrically induced underwater corro-
sion occasionally affect boats and the related compo-
nents. This corrosion appears as surface pitting
or
de-
terioration. These two types are
as
follows:
A.
Electrolysis
Electrolysis
is
the decomposition of chemical com-
pounds by electric current. Electrolysis can be caused
by the polarity of the dockside wiring system of the boat
being reversed from the power source
or
surrounding
boats,
an
improperly wired battery installation, other
boats that are in close proximity that have electrical
power leakages, or any other source close to the boat
that has electrical power leakage into the water. Stern
drive units are especially vulnerable to electrolysis.
However, it can attack a fiberglass hull and inboard
underwater gear. Make periodic inspections to deter-
mine if electrolysis damage exists. Then determine the
source of the problem.
If
the source cannot be found,
it
may be necessary to change the place of mooring.
The use of some shore power battery chargers, while
the boat is in the water and the battery
is
connected to
the system, can cause electrolysis. Have
an
ex-
perienced marine electrician ·review any battery
charger installation
to
ensure an electrolysis problem
will not develop.
Be
sure the battery connections are
properly made. Improper battery connection, espe-
cially the lack
of
a negative battery bonding cable on
dual engine boats,
is
a common cause of electrolysis.
B.
Galvanic
Corrosion
Electrical currents produced by two dissimilar metalsin
an electrolytiC solution
is
galvanic corrosion: Polluted
and salt water are much better electrolytic solutions
than clean, fresh water. Stern drive manufacturers
provide a sacrificial anode, either
as
a metal trim tab or
metal plate affixed to the boat transom. Periodic
inspection of this anode for decomposition, and its
replacement when
it
becomes worn, will increase the
longevity of stern drive units. Inboard boats, because
of the metal used for the underwater gear, are not as
affected by galvanic corrosion. However, if dockage
is
in
salt water, at a steel pier, near large metal boats, or
anywhere else where substantial metal
is
in
contact
with the water, some form of corrosion protection
should be provided.
E6
OMSB
CARVER
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