What wire size should a 125A main switch in a distribution cabinet be fitted with
The National Electrical Code (NEC) helps set electrical standards to protect against potential overloads, short circuits, and arc faults. What wire size for a 125 amp circuit? For a 125A circuit on a 125A breaker: Use 1 AWG copper (130A capacity) or 2/0 AWG aluminum (135A capacity). Common applications: 125A subpanels for large additions, ADUs, and commercial tenant spaces. Where it gets a bit more difficult is at 125 amp service 50 feet, 100 feet, 150 feet, 200 feet, and up to 500 feet away. These wire sizes provide the necessary ampacity (current-carrying capacity) while maintaining safety margins required by the National Electrical Code (NEC).
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