NEC-compliant electrical calculators for professional electricians. All apps work 100% offline.
NEC 2023 · Free · OfflineEMT, IMC, RMC, PVC conduit with Table 1 fill limits. Mix wire sizes, instant PASS/FAIL.
Residential load calculations per NEC 220.82 Optional Method. 26 appliance presets, permit-ready PDF.
Chapter 9 Tables 8 & 9 impedance data. Copper and aluminum, 3% compliance check.
Ampacity tables 310.16 & 310.17, temperature derating, conduit fill adjustment, termination check.
All standard metal boxes from Table 314.16(A). Conductors, clamps, devices, grounds. PASS/FAIL.
Full-load amps from Tables 430.248/250. Conductor sizing, overload, SCPD, disconnect rating.
Overcurrent protection sizing per 240.6(A). Continuous load rule, next-size-up, wire coordination.
EGC, GEC, and bonding jumper sizing per Tables 250.122, 250.66, 250.102(C)(1). Electrode exceptions, voltage drop adjustment.
Overcurrent protection per Table 450.3(B). Primary/secondary OCPD, FLA, conductor sizing.