ABYC Marine Electrical Certification Exam Review Questions with simplified answers
Every 18 inches. - How often (in inches) shall wire bundles be supported?
Insulated Metallic Hanger Clamps - What type of clamps are to be used for supporting wire
bundles when routed over engines and machinery?
40 lbs (E-11 Table XV) - What tensile force must a 10 Gauge crimp connector withstand for
one minute?
36 inches - What is the max allowed unsupported cable length for battery cables?
True - T or F: Running AC and DC conductors together is allowed so long as the AC
conductors are sheathed.
C. Unwanted open - The most common electrical circuit problem in marine applications is:
A. Short circuits
B. Too much continuity
C. Unwanted open
D. Inter circuit Short
D. Heat - The primary by-product of excessive electrical resistance is:
A. Increased Amperage
B. Increased Voltage
C. Reduced Ambient Temperature
D. Heat
1 HP = 746 Watts - One HP = how many watts?
D. TDR (time-domain reflectometer) - 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)
0 AWG - 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)?
Yellow - DC grounded conductors on new boats that are also equipped with AC systems
should use what color insulated wire?
16 AWG - What is the smallest guage wire allowed for unsheathed wire runs through the
boat?
False. Start batteries have a greater number of thinner plates within each cell. - T or F:
Compared to deep cycle (house) batteries, cranking batteries will have thicker lead plates
to facilitate the higher, short-duration current draws.
Cranking - Which type of battery generally recharges faster? Deep cycle or cranking?
Wire brush and backing soda. - What tool and common household staple are used to clean
battery terminals?
Most of the sulfuric acid has been absorbed into the lead plates, leaving mostly water in
the electrolyte. - Why might a fully-discharged wet-cell type battery freeze?
1 inch, 90 lbs or 2x the battery weight, for 1 minute in each direction. - 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?
True - T or F: it is ok to install batteries directly below an uninterrupted fuel line?
Must be protected with dielectric insulating material - What provision must be in place on
any fuel line located within 12 inches of a battery terminals?
80 F, 25 Amps, 10.5 Volts - 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)
90 minutes - According to ABYC, what is the minimum battery reserve capacity?
32 degrees F, 30 seconds, 7.2V - 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).
0 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).
,8 AWG - What is the largest guage wire that may be connected to a bettery with wing-nuts?
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. - 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).
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 12 V, 1500 CCA?
AIC = 2X mnfg's short-circuit rating or 100X nominal Ahr rating. - 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?
False. "Readily accessible" defines entry into the engine room in an emergency as
dangerous - use a remote battery switch. - 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.
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. -
Explain the "7-40-72" rule
Resetting mechanism cannot overrid over current interrupting mechanism. (Note: some
residential breakers are not trip free) - What does "trip free" breaker mean?
C. 14.1 V - 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
0.050 points of specific gravity below other cells = bad cell. - When testing a wet-cell
battery with a hydrometer, what threshold is used to determine a bad cell?
1.260 - 1.285 (temperature dependent) - When testing a wet-cell battery with a
hydrometer, what reading indicates a fully charged battery?
, 50% - 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?
C. Between 150% and 200% - 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%
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., -
T or F: A battery charger case shall be tied to the DC negative output terminal at the battery
charger.
In case of an internal short to the case, the AC grounding wire would not carry enough
current. - Why do battery chargers require a separate case connection to main AC
grounding bus and Engine negative / DC grounding bus?
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 is the minimal
wire size required for a battery charger case connection to DC ground/engine negative?
Class T fuse rated for appropriate AIC - What device is typically found to satisfy the
required OC protection between a battery charger and the batteries?
Batteries will feed back into solar array or wind generator coil and discharge (possibly
damage). Note: many voltage regulators have integral blocking diodes. - What may happen
to a solar array or wind generator used to charge batteries without a blocking diode?
24 inches or more (unless waterproof!) - How far above bilge water level must a battery
charger be mounted?
At least 24 inches - How far away from a gasoline tank must a pre-wired battery charger's
AC connection plug be located?
False. (only when installed in location that required GFCI per ABYC E-11) - T or F: All marine
inverters shall utilize an internal or external GFCI on their AC outlets.
Every 18 inches. - How often (in inches) shall wire bundles be supported?
Insulated Metallic Hanger Clamps - What type of clamps are to be used for supporting wire
bundles when routed over engines and machinery?
40 lbs (E-11 Table XV) - What tensile force must a 10 Gauge crimp connector withstand for
one minute?
36 inches - What is the max allowed unsupported cable length for battery cables?
True - T or F: Running AC and DC conductors together is allowed so long as the AC
conductors are sheathed.
C. Unwanted open - The most common electrical circuit problem in marine applications is:
A. Short circuits
B. Too much continuity
C. Unwanted open
D. Inter circuit Short
D. Heat - The primary by-product of excessive electrical resistance is:
A. Increased Amperage
B. Increased Voltage
C. Reduced Ambient Temperature
D. Heat
1 HP = 746 Watts - One HP = how many watts?
D. TDR (time-domain reflectometer) - 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)
0 AWG - 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)?
Yellow - DC grounded conductors on new boats that are also equipped with AC systems
should use what color insulated wire?
16 AWG - What is the smallest guage wire allowed for unsheathed wire runs through the
boat?
False. Start batteries have a greater number of thinner plates within each cell. - T or F:
Compared to deep cycle (house) batteries, cranking batteries will have thicker lead plates
to facilitate the higher, short-duration current draws.
Cranking - Which type of battery generally recharges faster? Deep cycle or cranking?
Wire brush and backing soda. - What tool and common household staple are used to clean
battery terminals?
Most of the sulfuric acid has been absorbed into the lead plates, leaving mostly water in
the electrolyte. - Why might a fully-discharged wet-cell type battery freeze?
1 inch, 90 lbs or 2x the battery weight, for 1 minute in each direction. - 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?
True - T or F: it is ok to install batteries directly below an uninterrupted fuel line?
Must be protected with dielectric insulating material - What provision must be in place on
any fuel line located within 12 inches of a battery terminals?
80 F, 25 Amps, 10.5 Volts - 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)
90 minutes - According to ABYC, what is the minimum battery reserve capacity?
32 degrees F, 30 seconds, 7.2V - 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).
0 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).
,8 AWG - What is the largest guage wire that may be connected to a bettery with wing-nuts?
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. - 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).
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 12 V, 1500 CCA?
AIC = 2X mnfg's short-circuit rating or 100X nominal Ahr rating. - 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?
False. "Readily accessible" defines entry into the engine room in an emergency as
dangerous - use a remote battery switch. - 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.
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. -
Explain the "7-40-72" rule
Resetting mechanism cannot overrid over current interrupting mechanism. (Note: some
residential breakers are not trip free) - What does "trip free" breaker mean?
C. 14.1 V - 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
0.050 points of specific gravity below other cells = bad cell. - When testing a wet-cell
battery with a hydrometer, what threshold is used to determine a bad cell?
1.260 - 1.285 (temperature dependent) - When testing a wet-cell battery with a
hydrometer, what reading indicates a fully charged battery?
, 50% - 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?
C. Between 150% and 200% - 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%
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., -
T or F: A battery charger case shall be tied to the DC negative output terminal at the battery
charger.
In case of an internal short to the case, the AC grounding wire would not carry enough
current. - Why do battery chargers require a separate case connection to main AC
grounding bus and Engine negative / DC grounding bus?
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 is the minimal
wire size required for a battery charger case connection to DC ground/engine negative?
Class T fuse rated for appropriate AIC - What device is typically found to satisfy the
required OC protection between a battery charger and the batteries?
Batteries will feed back into solar array or wind generator coil and discharge (possibly
damage). Note: many voltage regulators have integral blocking diodes. - What may happen
to a solar array or wind generator used to charge batteries without a blocking diode?
24 inches or more (unless waterproof!) - How far above bilge water level must a battery
charger be mounted?
At least 24 inches - How far away from a gasoline tank must a pre-wired battery charger's
AC connection plug be located?
False. (only when installed in location that required GFCI per ABYC E-11) - T or F: All marine
inverters shall utilize an internal or external GFCI on their AC outlets.
