Can 8 AWG copper wire carry 50 amps?

Yes, in conduit with 75 degree rated terminations, 8 AWG copper THHN is rated exactly 50 amps per NEC Table 310.16. In NM cable it is limited to the 60 degree column at 40 amps, so Romex for a 50 amp circuit must be 6 AWG copper.

What size aluminum wire do I need for 50 amps?

6 AWG aluminum is rated 50 amps in the 75 degree column of Table 310.16. Many electricians step up to 4 AWG aluminum for voltage drop or continuous loads.

What Wire Size Is Required for a 50 Amp Circuit?

A user asked the app what wire size a 50 amp circuit needs. The honest answer is that it depends on the wiring method, because the same copper conductor carries different ampacity depending on its insulation temperature rating and how it is installed. Under NEC 2023 Table 310.16, 8 AWG copper is rated 50 amps in the 75 degree C column and 6 AWG copper is rated 65 amps. Aluminum runs two sizes behind, with 6 AWG aluminum at 50 amps and 4 AWG at 65 amps in the same column.

Conduit versus cable changes the answer

If you are pulling THHN or THWN conductors in conduit and both terminations are rated 75 degrees, which nearly all modern breakers and lugs are, 8 AWG copper lands exactly on 50 amps and is compliant for a 50 amp breaker. If you are running NM cable, 334.80 caps the cable at the 60 degree column no matter what the conductor insulation says, and 8 AWG copper at 60 degrees is only 40 amps. That is why a 50 amp range or EV circuit in Romex has to be 6/3 NM, while the same circuit in EMT can legally be 8 AWG THHN. SE cable and MC cable get to use the 75 degree column in most dwelling applications, so 8 AWG copper MC also works.

When to upsize anyway

Continuous loads change the math. A load that runs 3 or more hours, like an EV charger, requires conductors and the breaker sized at 125 percent per 210.19(A) and 210.20(A). A 40 amp continuous EVSE on a 50 amp breaker is fine on 8 AWG THHN, but a 48 amp EVSE needs a 60 amp circuit and 6 AWG copper. Long runs deserve a voltage drop check too. Past roughly 70 feet on a loaded 50 amp circuit, stepping up to 6 AWG copper keeps you inside the informational 3 percent recommendation. And remember derating: more than three current carrying conductors in one raceway, or rooftop sunlight exposure, can pull that 8 AWG below 50 amps.

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