1-1/4 Inch Conduit Fill Chart

Q: How many #12 THHN wires fit in 1-1/4" conduit?

Up to 37 #12 THHN wires fit in 1-1/4" EMT conduit per NEC Chapter 9 Table C1, based on 40% fill for 3+ conductors.

Q: What is the fill area of 1-1/4" EMT conduit?

1-1/4" EMT conduit has an internal area of 0.49 sq inches. At 40% fill (3+ wires): 0.196 sq inches available. At 31% fill (over 2 wires): 0.152 sq inches.

Q: What are the NEC conduit fill rules?

1 wire: 53% fill. 2 wires: 31% fill. 3+ wires: 40% fill per NEC Chapter 9 Table 1. These percentages apply to the conduit internal cross-sectional area.

How many wires fit in 1-1/4" conduit? See the complete THHN wire fill chart for 1-1/4" EMT, PVC, and rigid conduit per NEC Chapter 9 Table C1. Common uses: 4-8 circuits, small sub-panel feeds.

1-1/4" Conduit Specifications

1-1/4" (1.25" trade size)

EMT Area

0.49 sq in

PVC Area

0.52 sq in

40% Fill

0.196 sq in

31% Fill

0.152 sq in

Common Use

4-8 circuits

THHN Wire Fill Chart — 1-1/4" EMT Conduit

Wire Size	Max Wires (40% fill)
#6 THHN	10 wires
#8 THHN	13 wires
#10 THHN	23 wires
#12 THHN	37 wires
#14 THHN	50 wires

Based on NEC Chapter 9 Table C1 for EMT conduit with THHN/THWN-2 conductors at 40% fill (3+ conductors).

NEC Conduit Fill Rules

1 conductor: 53% of conduit area. 2 conductors: 31% of conduit area. 3+ conductors: 40% of conduit area. These rules are per NEC Chapter 9 Table 1 and apply to all conduit types (EMT, PVC, rigid).

Equipment grounding conductors count toward fill but not toward ampacity derating. Bare grounds use less area than insulated conductors of the same gauge.

When to Use 1-1/4" Conduit

4-8 circuits, small sub-panel feeds. This size is used for larger residential and light commercial installations. Use our Conduit Fill Calculator for exact fill calculations with mixed wire sizes.

Disclaimer: Based on NEC Chapter 9 tables. Verify with local codes. Consult a licensed electrician.