WireFillChart

Free NEC 2023 wire fill chart and conduit fill calculator. EMT, IMC, RMC, PVC, flex. THHN, THWN-2, RHH. Live fill % plus geometric jamming risk hint.

Free live wire fill chart and conduit fill calculator for US electricians, inspectors, and engineers. Pick a conduit. Add conductors. Read the fill percentage. Compute geometric jamming risk hint. Calculations use the site’s transcribed Chapter 9 Tables 1 / 4 / 5 data. No signup. Advertising and analytics scripts load site-wide.

NEC 2023 Chapter 9 Table 1 sets base fill budgets of 53 % for one conductor, 31 % for two, and 40 % for three or more. For equal insulated conductor areas, Note 7 can accept a count above that base budget: divide the budget by one conductor’s area and round up when the fractional part is at least 0.8. Actual fill can therefore exceed the tier percentage. Different areas use strict budget comparison. This calculator runs its supported Chapter 9 Table 4 × Table 5 area calculations for EMT, IMC, RMC, PVC, FMC, LFNC, and ENT — every result includes fill %, NEC status, and geometric jamming risk for the conduit-ID / wire-OD ratio.

THHN (90°C dry) THWN-2 (90°C wet/dry) RHH (90°C dry; without outer covering) RHW-2 (90°C wet/dry; without outer covering) TW (60°C)

14 AWG 12 AWG 10 AWG 8 AWG 6 AWG 4 AWG 3 AWG 2 AWG 1 AWG 1/0 2/0 3/0 4/0 250 300 350 400 500 600 700 750 800 900 1000

Table 1 tier: 40 %. Note 7: not applied . The displayed percentage is actual fill; acceptance concerns area only.

An accepted res