Electrical Leakage Analysis
A useful tool for checking your boat’s electrical system
is a Volt-Ohm-Milliameter (commonly abbreviated VOM). Various
electronic stores (one large chain is Radio Shack) sell inexpensive
VOMs in the realm of $9.00 to $40.00. A high quality meter is
not required, and will corrode in the marine environment almost
as fast as a less expensive model. Most meters will show a
negative current if the leads are reversed. In making any tests,
reverse the tester leads if the needle moves under zero.
To test the vessel for leakage of battery current to' the
ship's ground system, disconnect the negative battery cable from the
engine. Turn the master switch to the 'OFF'posistion, and place all
circuit breakers on the electrical panel in the ’OFF position.
Set the VOM to the lowest DC voltage scale available. Place
one test lead from the VOM on the engine at the location from
which the negative battery cable was removed. Connect the other
test lead to the end of the disconnected battery cable. An indication
of current will indicate an electrical leak, probably in the
wiring running from the batteries to the master switch.
Keep all circuit breakers on the electrical panel in the 'OFF'
position and move the master switch selector to battery #1 then to
battery #2 position. An indication of electrical current from
either battery switch position is resultant from an electrical
leak either the wiring running from the back of the battery switch
to the engine starter motor or the wiring running from the switch
(or wire connected to the same terminal of the engine starter
motor as the large red battery cable) to the electrical panel.
Frequently the source of electrical leakage can be located by
selectively wiggling the wiring having the possibility of causing
the leak.
A further discussion of electrical leakage may be found in
a book titled THE TWELVE VOLT DOCTOR, published by Spa Creek
Development Corp., Third St., Annapolis, Md 21403. Mention that
you own a Freedom and recieve a 10% discount.
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