Ampacity — You’re Using the WRONG Column (Weakest Link Rule)

Which ampacity value are you actually supposed to use—60°C, 75°C, or 90°C? This is one of the most misunderstood rules in the NEC, and it’s a common mistake on both electrical exams and real-world installations. In this video, Paul from Electrical Code Academy explains the “weakest link” principle when working with conductor ampacity, including how terminal ratings and insulation ratings determine the correct ampacity from Table 310.16. Many electricians assume they can always use the 90°C column—but that’s not always correct. This video clears up the confusion so you can apply the rule properly. If you’ve ever second-guessed which column to use, this will make it clear. ⚡ TAKE YOUR TRAINING FURTHER 👉 https://fasttraxsystem.com 👉 https://FastTraxTube.com 👉 https://tradehog.net ⚡ WHAT YOU’LL LEARN The “weakest link” ampacity rule 60°C vs 75°C vs 90°C explained How terminals affect ampacity Common mistakes electricians make How this applies to exams 🏷️ HASHTAGS #Electrician #NEC #Ampacity #ElectricalTraining #CodeTalk #31016