What is the ampacity of an 8-3 (plus ground) aluminum SE cable supplying a range receptacle?

To determine the ampacity of an 8-3 (plus ground) aluminum SE cable, one must refer to the National Electrical Code (NEC) or similar standards regarding wire sizing and ampacity for conductors.

For an 8-gauge aluminum conductor, the ampacity is generally rated lower than copper conductors due to the differences in their conductivity. Specifically, the ampacity for an 8-gauge aluminum wire typically falls around 40 amps under standard conditions, assuming the wire is run in a typical environment and installation scenario.

The option indicating 40 amps fits within the standard ampacity given for an 8 AWG aluminum conductor when properly installed, which allows it to safely handle that current without overheating. It's important to consider factors such as the temperature rating of the insulation, the number of conductors in a conduit, and other installation conditions that might affect the ampacity—however, under normal conditions, 40 amps is the correct rating for an 8-3 aluminum SE cable.

This understanding is crucial for ensuring safety and efficiency in electrical installations, as using a conductor rated for an appropriate ampacity helps prevent overheating and potential hazards.