Since resistance causes heat, fires can result from improperly installed terminals. Crimp-on terminals have gained universal acceptance in marine wiring, but to work effectively they must be put on with the proper tools. The crimper needs to be matched to the terminal size being crimped, and should preferably make a double crimp. Once on the conductor and once to grip the insulation for strain and fatigue relief. It s need arises from the fact that if a short circuit develops in onboard wiring, high current flows occur, generating heat and causing cables to melt down.
Electrical fires are among the most common fires on board.
Fuses and circuit-breakers, which collectively are known as overcurrent protection devices, are the primary defense against electrical fires. Sizing is a function of the cable sizes in the circuit, not the amperage draw of the appliance in the circuit. A fuse or circuit breaker is sized to protect the smallest wire in its circuit. There are two columns in the ampacity table - one for use outside engine spaces, and one for use inside engine spaces. The reason for this is that engine rooms are often hot.