What is the ampacity rating of a 1/0 TW copper conductor?

The ampacity rating of a 1/0 TW copper conductor is indeed 125 amps. The term "ampacity" refers to the maximum amount of electric current a conductor or device can carry before sustaining immediate or progressive deterioration.

The rating generally considers the size of the conductor, the type of insulation, and the installation conditions, among other factors. For copper conductors, the ampacity ratings can vary based on the insulation type and the installation environment, but 1/0 copper conductors with THW, TW, or similar insulation typically have an ampacity rating of around 125 amps under standard conditions.

This understanding assists electricians in selecting the appropriate conductor for a specific application, ensuring safety and efficiency in electrical systems.