Automotive fuses are rated in

• A. Ohms
• B. Amps
• C. Watts
• D. Volts

Answer: (B)

Understanding how a fuse is rated focuses on the current it will allow before it opens. Fuses are rated in amperes, which tells you the maximum current the circuit can carry safely. In automotive systems, this is the key factor because wires and components are sized for a certain current; selecting the right amp rating protects the wiring from overheating without nuisance blows. If the circuit draws more current than the fuse rating, the fuse melts and interrupts the circuit, preventing damage.

The voltage rating on a fuse indicates the maximum voltage it can safely interrupt, but the rating you use to choose a fuse is the current in amps. Ohms, watts, and volts refer to resistance, power, and voltage, respectively, and are not the specifications used to determine when the fuse should blow.