Fill 'Er Up - The correct raceway fill depends on the conductor type and raceway type

摘要

Raceways must be large enough to hold conductors without overheating and avoid insulation damage during conductor pulls. Therefore, we must determine the maximum number and size of conductors to put in a given raceway. That limit is what we mean by raceway fill. Chapter 3 of the NEC contains Articles for a dozen different types of raceway, including conduit, EMT, and PVC. Chapter 9 and Annex C are the primary references for determining the correct raceway fill for a given application. Annex C contains a different raceway fill table for each raceway type, because each differs in its ability to dissipate heat.