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Systems
TYPICAL ELCI SYSTEM
TYPICAL ELCI SYSTEM OVERVIEW
The shore power terminates at the power inlet. At this
point electricity when energized travels through a main
ELCI breaker with leakage fault technology to the ship’s
main AC control panel with shore power main and aux-
iliary equipment breakers. The ELCI is located between
the shore power inlet and the ship’s main AC panel break-
ers.
After the shore power inlet AC electricity travels to each
of the ELCI breakers. The ELCI single pole breaker is
set up to trip should an overload or fault occur between
the breaker itself and the main AC control panel. If the
30 amp ELCI breaker trips nd the cause of the problem
before resetting the breaker.
The ELCI stands for “Equipment Leakage Circuit Inter-
rupter”. There are two potential failures in a boat’s elec-
trical system that can put people on or around a vessel at
risk of lethal electrical shock. In a properly functioning
marine electrical system, the same amount of AC current
ows in the hot and neutral wires.
However, should electricity “leak” from this intended
path in these two wires to ground, this condition is re-
ferred to as a “ground fault”. An example of this is an
insulation failure in the wiring of an appliance.
Furthermore, a ground fault can occur when the ground-
ing path is broke through a loose connection or broken
wire. As an example a shore power ground wire may
fail due to fatigue caused by constant motion and stress.
Faulty grounds can go undetected; a simple continuity
test may not reveal problems.
When these 2 conditions occur at the same time, it may
produce tragic results. The combination of a “ground
fault” and a faulty ground could result in the metal parts
of the vessel and underwater gear to become energized.
If this condition exists, besides being a hazard to person-
nel on board there is increased danger to swimmers near
the boat. The result could be shocking people on board
and swimmers could receive a paralyzing dose of electric-
ity and drown due to loss of muscle control.
An ELCI provides protection for the entire boat and fea-
tures a trip threshold which provides ground fault protec-
tion for the entire shore power system beyond the ELCI.
The ELCI protection on individual shore power lines
combined with GFCI’S will reduce the risk to those on
the boat, dock, and in the water surrounding the vessel.
Another feature of the ELCI is a “leakage fault” detector
located on the side of the ELCI breaker itself. The leak-
age fault feature detects a change in the neutral wire cur-
rent. Should the current change more than 30 milli-amps
or about 1/3 of an amp the unit senses the difference and
will “trip” the breaker causing the leakage fault LED to
illuminate red. This clearly indicates that the trip occurred
as a result of leakage. Before resetting the ELCI breaker
determine the cause of the leakage fault.
A proper operating alternating current system will display
a green illuminated LED at the “power” marked area of
the ELCI.
Periodically test the ELCI by depressing the “test” but-
ton. The breaker should “trip” indicating the system is
functioning properly. Simply reset the breaker. The leak-
age hazard helps prevent serious equipment damage and
possible re.
After the neutral and the 2-120 volt conductors exit the
ELCI they run directly to the ship’s main AC control
panel.
The ELCI can at times undergo a process called “nui-
sance tripping” which can cause a “tripped” breaker. This
can be caused by overloads in the electrical draw or some-
times caused from unbalanced loads. One way to mini-
mize the situation should it occur is to monitor closer the
energized devices on the vessel which will assist in keep-
ing the total amperage used to a minimum and the loads
between panel legs more balanced.
Note: It is always a good practice to keep the AC panel
legs as balanced as possible and always turn off breakers
not in use. Your vessel is not like a home with unlimited
energy resources. Remember to balance panel loads.
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