To keep it short, I am repairing some of the factory wiring for a mk3 2.0 fuel pump. One wire I am fixing is listed in the Bentley as "2,5" or 14 gauge awg. I bought some 14 gauge stranded wire to replace the way I have many times over the years. That is to say, paying no attention to voltage or amperage specs of the wire.

I did do some brief research this time. The wire manufacturer says it has a maximum amperage of 15. Everything online says that 14 gauge wire should carry no more than 15 amps. Yet this circuit, the fuel pump circuit, has 20amp fuses.

So can anyone explain why the automotive electrical experts who design the car use 14 gauge wire on circuits protected with 20 amp fuses? Perhaps its actually a <15amp circuit, and fuses are purposely used +5 amps higher than the circuit it is protecting runs, so that it doesn't blow with minor fluctuation in amps like 1 or 2 higher than to spec? I would be curious to know.