IMC was developed in the 1970s as a thin-wall alternative to rigid metal conduit (RMC) that weighs about one-third less. IMC ships with either a straight-tapped or integral coupling. It features a galvanized OD and corrosion-resistant ID coating.

Electrical Code Compliance

IMC is covered under Article 342 in the NEC^®.

IMC Sizing

IMC is available in trade sizes 1/2 through 4, and 10′ lengths. Threads on the uncoupled end are covered by industry color-coded thread protectors to protect the threads, keep them clean and sharp, and aid in trade size recognition. Thread protectors for trade sizes 1, 2, 3 and 4 are color-coded orange; trade sizes 1/2, 1 1/2, 2 1/2 and 3 1/2 are yellow; and trade sizes 3/4 and 1 1/4 are green.

Using IMC as a Substitute for RMC

IMC is interchangeable with galvanized RMC. Both have threads with a 3/4-inch-per-foot taper, use the same couplings and fittings, have the same support requirements and are permitted to be used in the same locations.

												Master Bundles
Trade Size Designator		Nominal Wt. per 100 Ft. (30.5m.)		Nominal Outside Diameter		Nominal Wall Thickness		Quantity in Primary Bundle		Quantity		Approx Wt.		Volume
US	Metric	lb.	kg	in.	mm	in.	mm	ft.	m	ft.	mm	lb.	kg	cu ft.	cu m
1/2	16	62	28.12	0.815	20.70	0.078	1.97	100	30.5	3500	1067	2170	984.3	26.4	0.7
3/4	21	84	38.10	1.029	26.14	0.083	2.10	50	15.2	2500	762	2100	952.5	33.5	0.9
1	27	119	53.98	1.290	32.77	0.093	2.35	100	30.5	1700	518	2023	917.6	32.1	0.9
1 1/4	35	158	71.67	1.638	41.59	0.095	2.41	-	-	1350	411	2133	967.5	34.7	1.0
1 1/2	41	194	88.00	1.883	47.82	0.100	2.54	-	-	1100	335	2134	968.0	35.0	1.0
2	53	256	116.12	2.360	59.93	0.105	2.67	-	-	800	244	2048	929.0	30.9	0.9
2 1/2	63	441	200.04	2.857	72.57	0.150	3.81	-	-	370	113	1632	740.3	33.5	0.9
3	78	543	246.30	3.476	88.29	0.150	3.81	-	-	300	91	1629	738.9	38.3	1.1
3 1/2	91	629	285.31	3.971	100.86	0.150	3.81	-	-	240	73	1510	684.9	41.7	1.2
4	103	700	317.52	4.466	113.44	0.150	3.81	-	-	240	73	1680	762.0	48.6	1.4