수리 사례

2026. 6. 30. 작업

증상

Why is a 12V outlet that provides 120W protected by a 20A fuse in my 2015 Forester?

처리 내용

The purpose of the fuse is to limit the current in the wire to prevent it from overheating. That could cause the insulation to melt or even start a fire. The other components in the circuit will (should) also selected to handle the same load. So, for example, the accessory outlet should also be able to handle a 20A load. The bottom line is that nothing in the circuit should fail before the fuse. Since fuses are designed so that they will tolerate a small overload for a long time (hours or even days at around 5% or 10%) and to blow more and more quickly as the overload increases, the other components in the circuit should also have been selected with that in mind. The graph at the bottom shows the relationship between overload and time to blow (trip) for Littlefuse's automotive blade fuses . Without seeing a schematic for the circuit serving the accessory outlet it's hard to say if the rating is based on an abundance of caution or other loads on the same circuit, or maybe even a bureauc