Question: how many amps is number 8 wire rated for?
Answer: Many techs will repeat these rules of thumb and rely on them in all circumstances: “Twelve-gauge wire is good for 20 amps, 10-gauge wire is good for 30 amps, 8-gauge is good for 40 amps, and 6-gauge is good for 55 amps,” and “The circuit breaker or fuse is always sized to protect the conductor [wire].”