NEC Reference Charts
Lookups for the conditions you are working in, not fixed tables. Each chart derives its values from the 2023 edition, states the rule that governs each row, and links to the calculator that takes project-specific inputs.
- NEC 310.16 Ampacity Chart with Derating AppliedWhat ampacity does this conductor actually have?310.16
- Wire Size Amp ChartWhat is the quick ampacity starting point for common wire sizes?310.16
- Ambient Temperature Correction FactorsHow does ambient temperature change allowable ampacity?310.15(B)(1)
- Conduit Fill Limits by Conductor CountWhich fill percentage applies to this raceway?Chapter 9 Table 1
- EMT Conduit Fill ChartHow much area is available in EMT conduit?Chapter 9 Table 4
- PVC Schedule 40 Conduit Fill ChartHow much area is available in PVC Schedule 40 conduit?Chapter 9 Table 4
- Insulated Conductor DimensionsWhich conductor area is used in conduit fill?Chapter 9 Table 5
- Copper vs Aluminum Wire SizeHow much larger does aluminum need to be than copper?310.16
- Breaker Size and Wire Size ChartWhich breaker and conductor sizes commonly pair together?240.4
- Equipment Grounding Conductor Size ChartWhat size EGC is tied to this overcurrent device?250.122
- NEC Adoption by StateWhich NEC edition should I select for my state?State and local adoption