Can 8 gauge wire handle 100 amps?

Eight gauge wire cannot handle 100 amps. Copper 8 AWG is good for 50 amps at 75C, and aluminum 8 AWG for 40. Feeding it 100 amps doubles its rating and turns the run into a heating element.

One hundred amps needs 3 AWG copper, or 1 AWG aluminum, and a 100 amp dwelling service can use 4 AWG copper or 2 aluminum under Table 310.12's 83 percent allowance.

The confusion usually comes from grounds: a 100 amp circuit's equipment ground is 8 AWG copper, and people read that table as a conductor table. The ground only carries fault current for moments; the hots carry the load all day.

No temperature column rescues 8 gauge here; even at 90C it reads 55.

The 8 gauge amps calculator shows the honest ceiling for both metals.