Ampacity is the maximum current a conductor can carry continuously without exceeding its temperature rating. Ampacity depends on conductor size (AWG/kcmil), insulation temperature rating (60°C, 75°C, 90°C), ambient temperature, and number of current-carrying conductors per NEC tables (e.g., Table 310.16). Worked example: A #12 AWG copper THHN (90°C) conductor is typically rated 30A in the 90°C column, but if termination is rated 60°C, allowable ampacity is limited to 20A (per 60°C column for #12).
Ampacity is the maximum current a conductor can carry continuously without exceeding its temperature rating. Ampacity depends on conductor size (AWG/kcmil), insulation temperature rating (60°C, 75°C, 90°C), ambient temperature, and number of current-carrying conductors per NEC tables (e.g., Table 310.16).
Worked example: A #12 AWG copper THHN (90°C) conductor is typically rated 30A in the 90°C column, but if termination is rated 60°C, allowable ampacity is limited to 20A (per 60°C column for #12).
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