Wire Size & Ampacity Calculator
The smallest conductor that carries your load, straight from NEC Table 310.16.
Read this before you pull wire
This is the base ampacity for a single run. It does not apply ambient-temperature correction or the bundling/derate factors for >3 current-carrying conductors (310.15). Those reduce capacity. Most equipment terminations are rated 75°C, so under 110.14(C) you usually size from the 75°C column even when using 90°C wire.
Informational only. This is not legal advice, and not an official government resource. Licensing rules change; always confirm against the official board source linked on this page before you renew, apply, or make a business decision. Trade Cert Hub is independent and not affiliated with any state licensing board. Some links are affiliate links, and we may earn a commission at no extra cost to you (full disclosure).
Never miss a renewal deadline
Get a reminder before your license expires, plus the year’s code and CE-rule changes for electricians. No spam, unsubscribe anytime.