Conduit Fill Calculator for Los Angeles, California Electricians
California (NEC 2022) electricians in Los Angeles use this free conduit fill calculator to verify that conductors fit within the 40% fill limit required by NEC Annex C for three or more conductors in a raceway.
Use the Calculator
Enter your conduit type, trade size, and conductor details for Los Angeles jobs below.
→ Open the Conduit Fill Calculator
Common Los Angeles Conduit Fill Scenarios
- 3/4″ EMT with 12 AWG THHN: NEC 2022 Annex C Table C1 allows up to 9 conductors at 40% fill. Common for Los Angeles residential and light commercial branch circuits.
- 1″ PVC Schedule 40 underground: Los Angeles underground feeders often use Schedule 40 PVC; check Table C11 of NEC 2022 Annex C for the correct fill limits.
- Mixed wire sizes: Use the calculator to sum cross-sectional areas and compare to the 40% limit when running mixed gauges in the same Los Angeles raceway.
Frequently Asked Questions
What is the conduit fill rule for Los Angeles, California?
Under NEC 2022 (adopted in California), the maximum fill for 3 or more conductors in any conduit is 40% of the conduit’s internal cross-sectional area (NEC Chapter 9, Table 1). Los Angeles contractors should verify any local amendments with the building department.
How many 12 AWG THHN wires fit in 3/4″ EMT for a Los Angeles job?
Per NEC 2022 Annex C Table C1, up to 9 conductors of 12 AWG THHN fit in 3/4″ EMT at 40% fill. Use the calculator to verify for your exact combination of conductor sizes and insulation types.