DC Marine Electrical: Fuses & Circuit Breakers

What is the primary purpose of a fuse in a marine electrical system?

• Reduce voltage drop

• Improve signal clarity

• Protect the wiring from overcurrent

• Boost battery performance

Which of the following is not a cause of a fuse blowing?

• Overloaded circuit

• Short circuit

• Undersized wire

• Low battery voltage

Where should fuses be installed in relation to the battery?

• At the load

• As close as possible to the battery

• In the middle of the wire run

• Near the grounding point

What type of fuse is best for protecting sensitive electronics?

• Slow-blow fuse

• Glass fuse

• Fast-acting fuse

• Manual reset breaker

What can happen if a fuse is sized too high for a given wire?

• It will trip too early

• The wire may overheat and cause a fire

• The system will run more efficiently

• The battery will drain

Circuit breakers can be reset, but fuses must be:

• Cooled off

• Polished

• Replaced

• Rewired

Which is not a valid location for a main fuse or breaker?

• Near the battery

• On the positive bus bar

• After a long wire run

• Near the grounding plate

A slow-blow fuse is useful for which type of device?

• LED light

• Chartplotter

• Electric motor

• VHF radio

What is one advantage of a circuit breaker over a fuse?

• Lower cost

• More sensitive to voltage

• Can be reset without replacement

• Doesn’t require a wire

What tool is most often used to crimp lugs onto marine wires?

• Multimeter

• Needle-nose pliers

• Ratcheting crimper

• Screwdriver