Structured Wiring

This is a great resource for anyone planning or performing structured wiring installations. We have used this table in the past to make sure we size conduits appropriately for current need + room for expansion.

trade size	inside diam. inch	inside diam. mm	cable outside diameter mm (in)
trade size	inside diam. inch	inside diam. mm	3.3 (0.13)	4.6 (0.18)	5.6 (0.22)	6.1 (0.24)	7.4 (0.29)	7.9 (0.31)	9.4 (0.34)	13.5 (0.53)	15.8 (0.62)	17.8 (0.70)
1/2	.622	16	1	1	0	0	0	0	0	0	0	0
3/4	.824	21	6	5	4	3	2	2	1	0	0	0
1	1.049	27	8	8	7	6	3	3	2	1	0	0
1-1/4	1.380	35	16	14	12	10	6	4	3	1	1	1
1-1/2	1.610	41	20	18	16	15	7	6	4	2	1	1
2	2.067	53	30	26	22	20	14	12	7	4	3	2
2-1/2	2.469	63	45	40	36	30	17	14	12	6	3	3
3	3.068	78	70	60	50	40	20	20	17	7	6	6
3-1/2	3.548	91	MAX	MAX	MAX	MAX	MAX	MAX	22	12	7	6
4	4.026	103	MAX	MAX	MAX	MAX	MAX	MAX	30	14	12	7
typical 2-pair CAT3 cable
typical 4-pair CAT3 cable
typical 4-pair CAT5E cable
typical 4-pair CAT6 (without divider) cable
typical 4-pair CAT6 (with divider) or 4-pair ScTP cable
typical 12-pair CAT3 unshielded cable
typical 25-pair CAT3 unshielded cable
typical 50-pair CAT3 unshielded cable
typical 50-pair CAT3 shielded ARMM cable
typical 100-pair CAT3 unshielded cable