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Raceway Fill Quick Chart NEC Ch.9 T.4

Maximum number of same-size THHN/THWN conductors in trade-size conduit at 40% fill.

EMT — Electrical Metallic Tubing

Wire Size	1/2"	3/4"	1"	1-1/4"	1-1/2"	2"	2-1/2"	3"	4"
14 AWG	12	22	35	61	84	138	241	364	598
12 AWG	9	16	26	46	64	104	182	275	452
10 AWG	5	10	16	28	39	64	112	169	278
8 AWG	3	6	9	16	22	36	64	96	158
6 AWG	2	4	7	12	16	26	46	69	114
4 AWG	1	2	4	7	10	16	28	43	70
3 AWG	1	1	4	6	8	14	24	36	60
2 AWG	1	1	3	5	7	11	20	30	50
1 AWG	1	1	1	4	5	8	15	22	37
1/0	—	1	1	3	4	7	12	19	31
2/0	—	1	1	2	4	6	10	16	26
3/0	—	1	1	2	3	5	9	13	22
4/0	—	1	1	1	2	4	7	11	18
250 kcmil	—	—	1	1	2	3	6	9	15
300 kcmil	—	—	1	1	1	3	5	8	13
350 kcmil	—	—	1	1	1	2	4	7	11
400 kcmil	—	—	—	1	1	2	4	6	10
500 kcmil	—	—	—	1	1	1	3	5	8

IMC — Intermediate Metal Conduit

Wire Size	1/2"	3/4"	1"	1-1/4"	1-1/2"	2"	2-1/2"	3"	4"
14 AWG	16	28	43	75	98	163	251	390	629
12 AWG	12	21	33	57	75	124	190	296	477
10 AWG	7	13	20	35	46	76	117	182	293
8 AWG	4	7	12	20	26	43	67	104	167
6 AWG	3	5	8	14	19	31	48	75	121
4 AWG	1	3	5	9	12	19	30	46	75
3 AWG	1	3	4	7	10	16	25	39	63
2 AWG	1	2	4	6	8	14	21	33	53
1 AWG	1	1	2	4	6	10	15	24	39
1/0	1	1	2	4	5	8	13	20	33
2/0	—	1	1	3	4	7	11	17	27
3/0	—	1	1	2	3	6	9	14	22
4/0	—	1	1	2	3	5	7	11	18
250 kcmil	—	—	1	1	2	4	6	9	15
300 kcmil	—	—	1	1	1	3	5	8	13
350 kcmil	—	—	1	1	1	3	4	7	11
400 kcmil	—	—	1	1	1	2	4	6	10
500 kcmil	—	—	—	1	1	2	3	5	8

RMC — Rigid Metal Conduit

Wire Size	1/2"	3/4"	1"	1-1/4"	1-1/2"	2"	2-1/2"	3"	4"
14 AWG	13	22	36	63	85	141	227	346	570
12 AWG	10	17	28	48	65	107	172	263	433
10 AWG	6	10	17	29	40	66	106	161	266
8 AWG	3	6	10	17	23	37	60	92	151
6 AWG	2	4	7	12	16	27	44	67	110
4 AWG	1	3	4	8	10	17	27	42	68
3 AWG	1	2	4	6	9	14	23	35	58
2 AWG	1	2	3	5	7	12	19	30	49
1 AWG	1	1	2	4	5	9	14	21	35
1/0	—	1	1	3	4	7	12	18	30
2/0	—	1	1	3	4	6	10	15	25
3/0	—	1	1	2	3	5	8	12	20
4/0	—	1	1	1	2	4	7	10	17
250 kcmil	—	—	1	1	2	3	5	8	14
300 kcmil	—	—	1	1	1	3	5	7	12
350 kcmil	—	—	1	1	1	2	4	6	10
400 kcmil	—	—	—	1	1	2	3	5	9
500 kcmil	—	—	—	1	1	1	3	4	7

Fill Percentages
1 conductor = 53% fill allowed. 2 conductors = 31% fill. 3 or more conductors = 40% fill. These percentages come from NEC Chapter 9, Table 1.

Mixed Wire Sizes?
This chart is for same-size conductors only. For mixed wire sizes, use the Conduit Fill Calculator which computes actual cross-sectional areas.

Values shown are for THHN/THWN insulation type. Other insulation types have different outer diameters and will yield different fill counts.

For reference only. Verify all results with the current NEC and local amendments. See Terms of Use.