ABYC MARINE ELECTRICAL CERTIFICATION 2024 LATEST
UPDATED EXAM 300 QUESTIONS WITH DETAILED VERIFIED
ANSWERS /A+ GRADE ASSURED
What is the preferred tool for tracing shorted and open circuits?
A. Ohm meter
B. Amp clamp
C. Volt meter
D. TDR (time-domain reflectometer) - (correct answer) D. TDR (time-domain
reflectometer)
A technician is installing a cable run from the batteries to the main DC panel board on
a boat as part of a refit. The boat has a 12-volt system and the distance form the panel
to the batteries is 15 ft. The maximum current draw from the panel is calculated at 90
amps. What guage cable should be used (minimum)? - (correct answer) 0 AWG
DC grounded conductors on new boats that are also equipped with AC systems should
use what color insulated wire? - (correct answer) Yellow
What is the smallest guage wire allowed for unsheathed wire runs through the boat? -
(correct answer) 16 AWG
T or F: Compared to deep cycle (house) batteries, cranking batteries will have thicker
lead plates to facilitate the higher, short-duration current draws. - (correct answer)
False. Start batteries have a greater number of thinner plates within each cell.
Which type of battery generally recharges faster? Deep cycle or cranking? - (correct
answer) Cranking
What tool and common household staple are used to clean battery terminals? -
(correct answer) Wire brush and backing soda.
Why might a fully-discharged wet-cell type battery freeze? - (correct answer) Most
of the sulfuric acid has been absorbed into the lead plates, leaving mostly water in the
electrolyte.
Batteries must be secured to prevent movement of more than ______ inches in any
direction when a pulling force of _____ or _____, whichever is less, is applied through
the center of gravity of the battery for how long? - (correct answer) 1 inch, 90 lbs or
2x the battery weight, for 1 minute in each direction.
T or F: it is ok to install batteries directly below an uninterrupted fuel line? - (correct
answer) True
,How often (in inches) shall wire bundles be supported? - (correct answer) Every 18
inches.
What type of clamps are to be used for supporting wire bundles when routed over
engines and machinery? - (correct answer) Insulated Metallic Hanger Clamps
What tensile force must a 10 Gauge crimp connector withstand for one minute? -
(correct answer) 40 lbs (E-11 Table XV)
What is the max allowed unsupported cable length for battery cables? - (correct
answer) 36 inches
T or F: Running AC and DC conductors together is allowed so long as the AC
conductors are sheathed. - (correct answer) True
The most common electrical circuit problem in marine applications is:
A. Short circuits
B. Too much continuity
C. Unwanted open
D. Inter circuit Short - (correct answer) C. Unwanted open
The primary by-product of excessive electrical resistance is:
A. Increased Amperage
B. Increased Voltage
C. Reduced Ambient Temperature
D. Heat - (correct answer) D. Heat
One HP = how many watts? - (correct answer) 1 HP = 746 Watts
When calculating AC loads for small galley appliances, how many watts should be
used for each 20 amp circuit? - (correct answer) 1500 Watts / 20 A circuit (E-
11.8.2.2.1.2)
T or F: when installing a remote solenoid for switching high-current draws like
windlass, bow-thruster, etc, a separate appropriately sized overcurrent protection
must be in place for both the low-current and high-current wiring of the solenoid. -
(correct answer) True
Describe the reason why a locked-rotor motor may not trip an overcurrent protection
device. - (correct answer) As the motor heats up, winding resistance increases
causing a corresponding decrease in current draw. Fire hazard. Thermal protection
device recommended in motors!
,For how long must a motor be able to sustain a locked rotor condition without inducing
a fire hazard? - (correct answer) seven hours (E-11.10.1.3.1)
T or F: if no standard rating OC protection device is available which equals 100% of the
allowable current for the conductor being protected, the next larger rating, up to 150%
of the conductor ampacity, may bee used - unless the load is a motor. - (correct
answer) True
Describe why a non-functional tachometer and charging system on a diesel engine
may be caused by a failed oil pressure sending unit. - (correct answer) On diesels,
the oil pressure sender may be used to switch alternator on/off and the trigger the
tachometer.
True or False: AC receptacles may be used for DC service, provided they are properly
labeled. - (correct answer) False
Tech A says that combined AC/DC panel boards are grounded via the DC negative bus.
Tech B says that such panel boards should be grounded to the AC grounding bus.
Which tech is right?
A. Tech A
B. Tech B
C. Both techs are correct
D. Neither tech is correct - (correct answer) B. Tech B
Start-in-gear protection switches should be open or closed when in neutral? -
(correct answer) Closed when in neutral (therefore, an open-circuit failure would
prevent engine starting)
Name three common gasses other than CO that may trigger a CO alarm: - (correct
answer) Styrene from curing fiberglass, methane from head/holding tank, hydrogen
from battery outgassing or refrigeration leaks
Name two likely possible causes of falsely trigger fire alarm in an engine room space.
- (correct answer) Excessive humidity, low supply voltage
T or F: boats with an enclosed accommodation compartment shall have an audible high
bilge-water alarm. - (correct answer) True
What gauge wire is required at a minimum for the primary down conductor from a
lightning Air Terminal? - (correct answer) 4 AWG
What is the minimal required surface area for lightning protection system's immersed
ground plate? - (correct answer) 1 sq. ft.
, What gauge wires is required for lightning protection system secondary conductors? -
(correct answer) 6 AWG
What is the maximum allowable trip current & time for ELCI/RCD at the main shore
power input? - (correct answer) 30 mA, 100 ms
T or F: CO detectors will also detect smoke in most situations. - (correct answer)
False
For true RMS inverters what is the relationship between peak and RMS voltage? -
(correct answer) Peak Voltage = 1.414 * RMS Voltage
or, V peak * .707 = V RMS
What is the max typically allowable % difference between true sinusoidal peak AC
voltage and harmonically distorted peak AC voltage? - (correct answer) 2-3%
On a standard 3-conductor AC outlet, which of the two blade conductors (i.e., not the
rounded GROUNDING conductor) is Hot and which is Neutral? - (correct answer)
shorter, thicker terminal is HOT
taller, narrower terminal is NEUTRAL
What provision must be in place on any fuel line located within 12 inches of a battery
terminals? - (correct answer) Must be protected with dielectric insulating material
Define: Battery reserve capacity = the number of minutes that a new, fully charged
battery at ______ degrees F can be continuously discharged at ______ amps while
maintaining _____ volts (for a 12 v battery) - (correct answer) 80 F, 25 Amps, 10.5
Volts
According to ABYC, what is the minimum battery reserve capacity? - (correct
answer) 90 minutes
Define: Marine Cranking Amps = the discharge load, in amperes, that a new, fully-
charged battery at _____ degrees F can deliver for ______ seconds while maintaining a
voltage of _____ volts (for a 12 v battery). - (correct answer) 32 degrees F, 30
seconds, 7.2V
Define: Cold Cranking Amps = the discharge load, in amperes, that a new, fully-charged
battery at _____ degrees F can deliver for ______ seconds while maintaining a voltage of
_____ volts (for a 12 v battery). - (correct answer) 0 degrees F, 30 seconds, 7.2V
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