Dimensions and percent area of conduit and tubing

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Trade Size Inches	Internal Diameter Inches	Total Area 100% Sq. In.	2 Wires 31% Sq. In.	Over 2 Wires 40% Sq. In.	1 Wire 53% Sq. In.
ELECTRICAL METALLIC TUBING
.5	0.622	0.304	0.094	0.122	0.161
.75	0.824	0.533	0.165	0.213	0.283
1	1.049	0.864	0.268	0.346	0.458
1.25	1.38	1.496	0.464	0.598	0.793
1.5	1.61	2.036	0.631	0.814	1.079
2	2.067	3.356	1.04	1.342	1.778
2.5	2.731	5.858	1.816	2.343	3.105
3	3.356	8.846	2.742	3.538	4.688
3.5	3.834	11.545	3.579	4.618	6.119
4	4.334	14.753	4.573	5.901	7.819
ELECTRICAL NONMETALLIC TUBING
.5	0.56	0.246	0.076	0.099	0.131
.75	0.76	0.454	0.141	0.181	0.24
1	1	0.785	0.243	0.314	0.416
1.25	1.34	1.41	0.437	0.564	0.747
1.5	1.57	1.936	0.6	0.774	1.026
2	2.02	3.205	0.994	1.282	1.699
2.5	-	-	-	-	-
3	-	-	-	-	-
3.5	-	-	-	-	-
4	-	-	-	-	-
FLEXIBLE METAL CONDUIT
.375	0.384	0.116	0.036	0.046	0.061
.5	0.635	0.317	0.098	0.127	0.168
.75	0.824	0.533	0.165	0.213	0.282
1	1.02	0.817	0.253	0.327	0.433
1.25	1.275	1.277	0.396	0.511	0.677
1.5	1.538	1.857	0.576	0.743	0.984
2	2.04	3.269	1.013	1.307	1.732
2.5	2.5	4.909	1.522	1.964	2.602
3	3	7.069	2.191	2.827	3.746
3.5	3.5	9.621	2.983	3.848	5.099
4	4	12.566	3.896	5.027	6.66
INTERMEDIATE METAL CONDUIT
.375	-	-	-	-
.5	0.66	0.342	0.106	0.137	0.181
.75	0.864	0.586	0.182	0.235	0.311
1	1.105	0.959	0.297	0.384	0.508
1.25	1.448	1.646	0.51	0.658	0.872
1.5	1.683	2.223	0.689	0.889	1.178
2	2.15	3.629	1.125	1.452	1.923
2.5	2.557	5.135	1.592	2.054	2.722
3	3.176	7.922	2.456	3.169	4.199
3.5	3.671	10.584	3.281	4.234	5.61
4	4.166	13.631	4.226	5.452	7.224
LIQUIDTIGHT FLEXIBLE NONMETALLIC CONDUIT (TYPE FNMC-B* - refer to Section 351-22(2))
.375	0.494	0.192	0.059	0.077	0.102
.5	0.632	0.314	0.097	0.125	0.166
.75	0.83	0.541	0.168	0.216	0.287
1	1.054	0.872	0.27	0.349	0.462
1.25	1.395	1.528	0.474	0.611	0.81
1.5	1.588	1.979	0.614	0.792	1.049
2	2.033	3.245	1.006	1.298	1.72
LIQUIDTIGHT FLEXIBLE NONMETALLIC CONDUIT (TYPE FNMC-A* - refer to Section 351-22(1))
.375	0.495	0.192	0.06	0.077	0.102
.5	0.63	0.312	0.097	0.125	0.165
.75	0.825	0.535	0.166	0.214	0.283
1	1.043	0.854	0.265	0.341	0.452
1.25	1.383	1.501	0.465	0.6	0.796
1.5	1.603	2.017	0.625	0.807	1.069
2	2.063	3.341	1.036	1.336	1.771
LIQUIDTIGHT FLEXIBLE METAL CONDUIT
.375	0.494	0.192	0.059	0.077	0.102
.5	0.632	0.314	0.097	0.125	0.166
.75	0.83	0.541	0.168	0.216	0.287
1	1.054	0.872	0.27	0.349	0.462
1.25	1.395	1.528	0.474	0.611	0.81
1.5	1.588	1.979	0.614	0.792	1.049
2	2.033	3.245	1.006	1.298	1.72
2.5	2.493	4.879	1.513	1.952	2.586
3	3.085	7.475	2.317	2.99	3.962
3.5	3.52	9.731	3.017	3.893	5.158
4	4.02	12.692	3.935	5.077	6.727
RIGID METAL CONDUIT
.375	-	-	-	-	-
.5	0.632	0.314	0.097	0.125	0.166
.75	0.836	0.549	0.17	0.22	0.291
1	1.063	0.888	0.275	0.355	0.47
1.25	1.394	1.526	0.473	0.61	0.809
1.5	1.624	2.071	0.642	0.829	1.098
2	2.083	3.408	1.056	1.363	1.806
2.5	2.489	4.866	1.508	1.946	2.579
3	3.09	7.499	2.325	3	3.975
3.5	3.57	10.01	3.103	4.004	5.305
4	4.05	12.883	3.994	5.153	6.828
5	5.073	20.213	6.266	8.085	10.713
6	6.093	29.158	9.039	11.663	15.454
RIGID PVC CONDUIT, SCHEDULE 80
.5	0.526	0.217	0.067	0.087	0.115
.75	0.722	0.409	0.127	0.164	0.217
1	0.936	0.688	0.213	0.275	0.365
1.25	1.255	1.237	0.383	0.495	0.656
1.5	1.476	1.711	0.53	0.684	0.907
2	1.913	2.874	0.891	1.15	1.152
2.5	2.29	4.119	1.277	1.647	2.183
3	2.864	6.442	1.997	2.577	3.414
3.5	3.326	8.688	2.693	3.475	4.605
4	3.786	11.258	3.49	4.503	5.967
5	4.768	17.855	5.535	7.142	9.463
6	5.709	25.598	7.935	10.239	13.567
RIGID PVC CONDUIT, SCHEDULE 40 & HDPE CONDUIT
.5	0.602	0.285	0.088	0.114	0.151
.75	0.804	0.508	0.157	0.203	0.269
1	1.029	0.832	0.258	0.333	0.441
1.25	1.36	1.453	0.45	0.581	0.77
1.5	1.59	1.986	0.616	0.794	1.052
2	2.047	3.291	1.02	1.316	1.744
2.5	2.445	4.695	1.455	1.878	2.488
3	3.042	7.268	2.253	2.907	3.852
3.5	3.521	9.737	3.018	3.895	5.161
4	3.998	12.554	3.892	5.022	6.654
5	5.016	19.761	6.126	7.904	10.473
6	6.031	28.567	8.856	11.427	15.141
TYPE A, RIGID PVC CONDUIT
.5	0.7	0.385	0.119	0.154	0.204
.75	0.91	0.65	0.202	0.26	0.345
1	1.175	1.084	0.336	0.434	0.575
1.25	1.5	1.767	0.548	0.707	0.937
1.5	1.72	2.324	0.72	0.929	1.231
2	2.155	3.647	1.131	1.459	1.933
2.5	2.635	5.453	1.69	2.181	2.89
3	3.23	8.194	2.54	3.278	4.343
3.5	3.69	10.694	3.315	4.278	5.668
4	4.18	13.723	4.254	5.489	7.273
TYPE EB, PVC CONDUIT
2	2.221	3.874	1.201	1.55	2.053
2.5	-	-	-	-	-
3	3.33	8.709	2.7	3.484	4.616
3.5	3.804	11.365	3.523	4.546	6.024
4	4.289	14.448	4.479	5.779	7.657
5	5.316	22.195	6.881	8.878	11.764
6	6.336	31.53	9.774	12.612	16.711

Reprinted with permission from NFPA 70-1999, the National Electrical Code®, Copyright 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the referenced subject which is represented only by the Standard in its entirety.