- A boat owner should know some of the basics of electrical wiring and
circuit protection before tackling any electrical projects aboard his craft.
Following are the answers to a few commonly asked questions about circuit
protection that should help make these projects easier for the beginner.
What is circuit protection?
Circuit protection is the intentional installation of a "weak link",
such as a fuse or circuit breaker, in an electrical circuit.
What do fuses and circuit breakers protect against?
They prevent excessive amperage from traveling through a wire, which
can damage electrical and electronic equipment. Too much amperage can also
cause a wire to overheat and melt or burn its insulation, causing a fire.
How much amperage can a wire safely carry?
The American Boat and Yacht Council (ABYC) publishes recommendations
on how much amperage each size of wire should carry. For example, it says
wire -- with 105'C insulation and conducting less than 50 volts in a non-engine
space area -- can handle up to 20 amps if it is 18AWG gauge, 60 amps if
10AWG, 210 amps if 2AWG and 445 amps if 4/OAWG. For more details, contact
the ABYC at 410-956-1050. If a wire is properly sized, why is a fuse or
circuit breaker necessary? The circuit may become accidentally grounded,
allowing a dangerous amount of amperage flow. Equipment failure, improper
maintenance or an exposed wire contacting a grounded surface can cause this
problem.
How does a fuse or circuit breaker stop the
amperage flow?
They respond to the high heat or large magnetic field generated by excessive
amperage. Fuses only respond to heat and have a special link that melts
at high temperatures. Circuit breakers can be designed to respond to heat,
the magnetic field or a combination of both. |