Sizing HVAC Branch Circuits: The 125% Rule for Motor-Compressors! #NECExam #Electrician #HVAC

Sizing conductors for air-conditioning and refrigeration equipment isn't the same as sizing a standard motor circuit. In this video, we break down Question 20 from our simulated exam to show you exactly which NEC Article governs these calculations and how to handle a "combined" load of a compressor and a fan motor. We walk through the math to find the minimum circuit ampacity (MCA) and select the correct conductor size from Table 310.16. 📋 Question Covered: What size minimum branch-circuit conductor is required for a 25A refrigerant motor-compressor with a 2A fan, terminals rated 75°C? A. 14 AWG B. 12 AWG C. 10 AWG D. 8 AWG 📖 Where to Look in the 2023 NEC: Keywords to Search: Refrigerant motor-compressor, branch-circuit conductors, HVAC sizing. Relevant Code Section: 440.33: Conductors supplying one or more motor-compressors with other loads (125% of the largest motor-compressor + 100% of other loads) Table 310.16: Conductor Ampacities. 💡 Pro Tip: When you see "refrigerant motor-compressor," stop looking at Article 430 and head straight to Article 440. The math for this question is: (25A × 1.25) + 2A = 33.25A. Looking at the 75°C column of Table 310.16, a 10 AWG copper conductor is rated for 35A, which safely covers our 33.25A requirement. ✅ Subscribe for more NEC exam breakdowns! 👍 Like & Share to help fellow electricians master the Code! #Electrician #MasterElectrician #NECExam #JourneymanExam #ElectricalCode #NEC #ElectricianTraining #ThinkLikeAMasterElectrician #ElectricalApprentice #ElectricalExamPrep #JourneymanElectrician #tradeswoman #womenintrades