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ABYC Marine Electrical Certification Exam | Marine
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When using a high-resolution amp clamp on a shore power cord and activating AC circuits one by one, the technician notes that the AC leakage current measured increases with each appliance. This most likely indicates: A. An open-circuit in the grounding conductor on the dock B. Excessively high voltage delivered by the utility company C. Excessive voltage drops in the AC power supply to the boat D. A neutral-to-gound link at the boats AC panel board ---------CORRECT ANSWER-- ---------------D. A neutral-to-gound link at the boats AC panel board A system voltmeter shall be installed on the main panel board if the system is permanently connected to: A. Inverter B. Generator C. Motor D. B & C above E. All of the above ---------CORRECT ANSWER-----------------E. All of the above Two techs are rewiring an old sailboat. Tech A says they should use all series circuits to keep the wiring clean and simple. Tech B
says series circuits should only serve a single load. Who is correct? a. Tech A b. Tech B c. Both are right. d. Neither are right. ---------CORRECT ANSWER-----------------d. Neither are right. According to ABYC, maximum current carrying capacity of a 10 gauge wire, 105 degree C insulation, inside the engine room when bundled with 2 other current carrying wires would be? a. 60 amps b. 51 amps c. 42 amps d. 35.7 amps ---------CORRECT ANSWER-----------------d. 35.7 amps What is the expected voltage across a 'closed' switch that is operating properly a. It should read current battery voltage b. It can be up to 10% less than battery voltage c. It should read '0' VDC d. Not enough information provided ---------CORRECT ANSWER-----------------c. It should read '0' VDC
What does "trip free" circuit breaker mean? a. The breaker is inexpensive b. The breaker will have lots of nuisance trips c. The breaker will trip out regardless of conditions d. The breaker will only trip at 150% of its rated amperage ---------CORRECT ANSWER-----------------c. The breaker will trip out regardless of conditions maximum current carrying capacity for an flexible cord of 16 AWG with 2 current carrying conductors inside the engine spaces is a. 6 amps b. 8 amps c. 10 amps d. 20 amps ---------CORRECT ANSWER-----------------b. 8 amps (E-11 Table XII Conductor Ampacity - Flexible Cords) A diode is a semiconductor that passes current a. in any direction b. only with high voltages c. only in one direction d. when used as a triggering device ---------CORRECT ANSWER-----------------c. only in one direction
Allowable amperage for AC conductors of 14 AWG, 105 degree C insulation, outside the engine spaces, when 2 current carrying conductors are bundled together is a. 35 amps b. 24.5 amps c. 20.8 amps d. none of the above ---------CORRECT ANSWER-----------------b. 24.5 amps T or F: Pigtails less than 7 inches (175mm) in length are exempt from overcurrent protection requirements. ---------CORRECT ANSWER-----------------True Allowable amps less than 50 volts (not bundled). You have a cable that runs from a battery to a bow thruster. All components are in the forward cabin. The wire is good 105 C rated #0 AWG. How many amps can safely pass through that cable? a. 200 b. 242. c. 285 d. 330 ---------CORRECT ANSWER-----------------c. 285 Pigtails less than 7 inches (175mm) in length are exempt from overcurrent protection requirements. A pigtail is defined as: a. A factory molded cord set for shorepower.
What is a possible problem with installing a new solid state Voltage regulator to replace a manual one? a. Overcurrent protection will have to match new amperage draw from device. b. There could be severe radio interference from the new device. c. Reverse influx could result, and diodes will have to be installed to modify voltage flow. d. None of the above ---------CORRECT ANSWER-----------------b. There could be severe radio interference from the new device. (T or F) Impedance can be defined as the total resistance flow in a D.C. system ---- -----CORRECT ANSWER-----------------F (impedance refers to AC systems) When installing a starter over current protection must be within inches of the battery. A. 7" B. 40" C. 72" D. None of the above ---------CORRECT ANSWER-----------------D. None of the above A neutral safety switch is used for: a. Safely switching between forward and reverse without damaging transmission b. Not allowing the engine to start with gear in neutral
c. Safely allowing someone to be in the water (like skier) without risk of propeller strike d. Not allowing the engine to start when not in neutral ---------CORRECT ANSWER-- ---------------d. Not allowing the engine to start when not in neutral A successful customer experience includes: a. Being neat and prompt b. Asking question to verify a complaint c. Listening to the customer d. All of the above ---------CORRECT ANSWER-----------------d. All of the above In the formula for circular mils, for our purposes "K" is equal to 10.75. What does this number represent? a. The wire thickness b. The resistivity of copper c. The rating of the wire insulation d. Black Magic ---------CORRECT ANSWER-----------------b. The resistivity of copper All of the following could cause a conductor to overheat except. a. Undersize conductor b. Excessive amperage c. Insulation temperature rating too low
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 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.
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.
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
According to ABYC, what is the maximum distance allowed between a boat's shore power connection and the main overcurrent protection device? --------- CORRECT ANSWER-----------------10' What is an ELCI and where is it required to be installed? ---------CORRECT ANSWER-----------------Equipment Leakage Current Interrupter - within 10 feet of shore power connection unless an isolation transformer is located within 10' of shore power connection. T or F: When more than one option for shore power inlet is installed on a boat, the shore power neutrals shall be tied together on the boat. ---------CORRECT ANSWER-----------------False, they must be isolated to prevent shock hazard at the unutilizd shore power connector pins. What ampacity is required for wire and terminals connecting a galvanic islolator? ---------CORRECT ANSWER-----------------At least 135% of isloator's nominal rating. (A-28.11.1) What is the general rule for use of friction connectors? ---------CORRECT ANSWER- ----------------Ampacity < 20 Amps, voltage drop across terminals < 50 mV @ 20 A flow, no separation with a one-minute pull of 6 lb force.
When measuring temperature to determine potential electrical issues involving excessive connector resistance, what is the threshold for concern? --------- CORRECT ANSWER-----------------> 25 degrees above ambient According to the ABYC, the shore-power grounded conductor should: A. Be connected to the AC neutral B. Not be grounded on the boat C. Be connected to the engine common positive terminal or its bus D. Be tied to the battery isolator ---------CORRECT ANSWER-----------------B. Not be grounded on the boat If a customer complains about receiving shocks from her boat when shore power is active, the technican should first test: A. Polarity check of shore cord B. Polarity check of the battery system C. Current Leakage Test D. Converter voltage check ---------CORRECT ANSWER-----------------A. Polarity check of shore cord A customer is complaining about low-voltage at the AC panel. What should you do first? A. Re-calibrate the panel meter B. Check the voltage at the dock pedestal
