ABYC Marine Electrical Certification Exam Review
2026/2027 version verified with correct solutions
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
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
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
What is the largest guage wire that may be connected to a bettery with wing-nuts?-
correct answer >>>8 AWG
Per ABYC E-10, a battery switch must be installed in the positive conductor from each
battery bank with a CCA rating greater than ____ (or greater than _____ Ah if CCA
rating not available).- correct answer >>>800 CCA or 100 Ahr (exceptions: electronic
equipment with battery backed memories; safety equipment such as bilge pumps,
alarms, CO detectors, bilge blowers; battery chargers; I'm pressed current systems.
What is the minimum ampere interrupting capacity (AIC) for main overcurrent protection
on a battery bank rated at 12 V, 1500 CCA?- correct answer >>>AIC = 5000 Amps (E-
11 table IV-A)
What is the minimum ampere interrupting capacity (AIC) for main overcurrent protection
on a battery bank rated at more than 2200 CCA or more than 500 Ahr?- correct answer
>>>AIC = 2X mnfg's short-circuit rating or 100X nominal Ahr rating.
T or F: it is ok to mount a battery switch inside an engine room, because ABYC startes
that it must be located as close to the batteries as practical.- correct answer >>>False.
"Readily accessible" defines entry into the engine room in an emergency as dangerous
- use a remote battery switch.
Explain the "7-40-72" rule- correct answer >>>Overcurrent protection must be located
withing 7 inches of the power source unless contained within a sheath, in which case it
may be up to 40 inches away. If the power source is a battery and the conductors are
sheathed, OC may be up to 72 inches away.
What does "trip free" breaker mean?- correct answer >>>Resetting mechanism cannot
overrid over current interrupting mechanism. (Note: some residential breakers are not
trip free)
The maximum sustained charging voltage acceptable to some gell cell battery
manufacturers is:
A. 13.8 V
B. 14.5 V
C. 14.1 V
D. 13.2 Vll- correct answer >>>C. 14.1 V
When testing a wet-cell battery with a hydrometer, what threshold is used to determine
a bad cell?- correct answer >>>0.050 points of specific gravity below other cells = bad
cell.
, When testing a wet-cell battery with a hydrometer, what reading indicates a fully
charged battery?- correct answer >>>1.260 - 1.285 (temperature dependent)
When testing a fully charged start battery for capacity with a load tester, what % of CCA
rating should be induced by the load to test resulting voltage?- correct answer >>>50%
Most engine-driven alternators are optimally spun at what percentage of engine RPMs?
A. Between 10% and 50%
B. Less than 10%
C. Between 150% and 200%
D. Greater than 200%- correct answer >>>C. Between 150% and 200%
T or F: A battery charger case shall be tied to the DC negative output terminal at the
battery charger.- correct answer >>>False. the battery charger case shall be tied to the
engine negative terminal/bus, along with the negative output terminal of the battery
charger, not at the battery charger case itself.,
Why do battery chargers require a separate case connection to main AC grounding bus
and Engine negative / DC grounding bus?- correct answer >>>In case of an internal
short to the case, the AC grounding wire would not carry enough current.
What is the minimal wire size required for a battery charger case connection to DC
ground/engine negative?- correct answer >>>No smaller than 1 size below the DC
current carrying conductors between the charger and batteries - provided OC protection
on positive DC output is no greater than 135% of DC grounding cable ampacity and
conductor is no smaller than 16 AWG.
What device is typically found to satisfy the required OC protection between a battery
charger and the batteries?- correct answer >>>Class T fuse rated for appropriate AIC
What may happen to a solar array or wind generator used to charge batteries without a
blocking diode?- correct answer >>>Batteries will feed back into solar array or wind
generator coil and discharge (possibly damage). Note: many voltage regulators have
integral blocking diodes.
How far above bilge water level must a battery charger be mounted?- correct answer
>>>24 inches or more (unless waterproof!)
How far away from a gasoline tank must a pre-wired battery charger's AC connection
plug be located?- correct answer >>>At least 24 inches
T or F: All marine inverters shall utilize an internal or external GFCI on their AC outlets.-
correct answer >>>False. (only when installed in location that required GFCI per ABYC
E-11)
2026/2027 version verified with correct solutions
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
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
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
What is the largest guage wire that may be connected to a bettery with wing-nuts?-
correct answer >>>8 AWG
Per ABYC E-10, a battery switch must be installed in the positive conductor from each
battery bank with a CCA rating greater than ____ (or greater than _____ Ah if CCA
rating not available).- correct answer >>>800 CCA or 100 Ahr (exceptions: electronic
equipment with battery backed memories; safety equipment such as bilge pumps,
alarms, CO detectors, bilge blowers; battery chargers; I'm pressed current systems.
What is the minimum ampere interrupting capacity (AIC) for main overcurrent protection
on a battery bank rated at 12 V, 1500 CCA?- correct answer >>>AIC = 5000 Amps (E-
11 table IV-A)
What is the minimum ampere interrupting capacity (AIC) for main overcurrent protection
on a battery bank rated at more than 2200 CCA or more than 500 Ahr?- correct answer
>>>AIC = 2X mnfg's short-circuit rating or 100X nominal Ahr rating.
T or F: it is ok to mount a battery switch inside an engine room, because ABYC startes
that it must be located as close to the batteries as practical.- correct answer >>>False.
"Readily accessible" defines entry into the engine room in an emergency as dangerous
- use a remote battery switch.
Explain the "7-40-72" rule- correct answer >>>Overcurrent protection must be located
withing 7 inches of the power source unless contained within a sheath, in which case it
may be up to 40 inches away. If the power source is a battery and the conductors are
sheathed, OC may be up to 72 inches away.
What does "trip free" breaker mean?- correct answer >>>Resetting mechanism cannot
overrid over current interrupting mechanism. (Note: some residential breakers are not
trip free)
The maximum sustained charging voltage acceptable to some gell cell battery
manufacturers is:
A. 13.8 V
B. 14.5 V
C. 14.1 V
D. 13.2 Vll- correct answer >>>C. 14.1 V
When testing a wet-cell battery with a hydrometer, what threshold is used to determine
a bad cell?- correct answer >>>0.050 points of specific gravity below other cells = bad
cell.
, When testing a wet-cell battery with a hydrometer, what reading indicates a fully
charged battery?- correct answer >>>1.260 - 1.285 (temperature dependent)
When testing a fully charged start battery for capacity with a load tester, what % of CCA
rating should be induced by the load to test resulting voltage?- correct answer >>>50%
Most engine-driven alternators are optimally spun at what percentage of engine RPMs?
A. Between 10% and 50%
B. Less than 10%
C. Between 150% and 200%
D. Greater than 200%- correct answer >>>C. Between 150% and 200%
T or F: A battery charger case shall be tied to the DC negative output terminal at the
battery charger.- correct answer >>>False. the battery charger case shall be tied to the
engine negative terminal/bus, along with the negative output terminal of the battery
charger, not at the battery charger case itself.,
Why do battery chargers require a separate case connection to main AC grounding bus
and Engine negative / DC grounding bus?- correct answer >>>In case of an internal
short to the case, the AC grounding wire would not carry enough current.
What is the minimal wire size required for a battery charger case connection to DC
ground/engine negative?- correct answer >>>No smaller than 1 size below the DC
current carrying conductors between the charger and batteries - provided OC protection
on positive DC output is no greater than 135% of DC grounding cable ampacity and
conductor is no smaller than 16 AWG.
What device is typically found to satisfy the required OC protection between a battery
charger and the batteries?- correct answer >>>Class T fuse rated for appropriate AIC
What may happen to a solar array or wind generator used to charge batteries without a
blocking diode?- correct answer >>>Batteries will feed back into solar array or wind
generator coil and discharge (possibly damage). Note: many voltage regulators have
integral blocking diodes.
How far above bilge water level must a battery charger be mounted?- correct answer
>>>24 inches or more (unless waterproof!)
How far away from a gasoline tank must a pre-wired battery charger's AC connection
plug be located?- correct answer >>>At least 24 inches
T or F: All marine inverters shall utilize an internal or external GFCI on their AC outlets.-
correct answer >>>False. (only when installed in location that required GFCI per ABYC
E-11)
