4" PVC Sch 40 conduit fill

4" Rigid PVC conduit, Schedule 40 has an inside area of 12.554 sq in (3.998 in across). Three or more wires may take 40 % of it: 5.0216 sq in.

One wire, 53 %: 6.6536 sq in
Two wires, 31 %: 3.8917 sq in
Three or more, 40 %: 5.0216 sq in
Nipple, 60 %: 7.5324 sq in
Support: Every 7 ft, 3 ft from boxes
Sold in: 10 ft sticks

27 #1/0 THHN, the most it may hold, drawn to scale

How many wires fit in 4" PVC Sch 40

All wires the same size and type, by Annex C's method. For a mix of sizes, open the calculator.

Wire size	THHN/THWN-2	XHHW-2	THW/THW-2
14 AWG	517	361	361
12 AWG	377	277	277
10 AWG	238	206	206
8 AWG	137	115	115
6 AWG	99	85	69
4 AWG	61	61	51
3 AWG	51	52	44
2 AWG	43	44	37
1 AWG	32	32	26
1/0 AWG	27	27	22
2/0 AWG	22	23	19
3/0 AWG	18	19	16
4/0 AWG	15	15	13
250 kcmil	12	13	11
300 kcmil	11	11	9
350 kcmil	9	9	8
400 kcmil	8	8	7
500 kcmil	7	7	6
600 kcmil	5	5	5
700 kcmil	5	5	4
750 kcmil	4	4	4
800 kcmil	4	4	4
900 kcmil	4	4	3
1000 kcmil	3	3	3

Smaller: 3-1/2" PVC Sch 40 Bigger: 5" PVC Sch 40

Other 4" conduit

Conduit	Inside area	#14	#12	#10	#8	#6
Rigid PVC conduit, Schedule 40	12.554	517	377	238	137	99
Electrical metallic tubing	14.753	608	443	279	161	116
Intermediate metal conduit	13.631	562	410	258	149	107
Rigid metal conduit (RMC, GRC)	12.882	531	387	244	140	101
Rigid PVC conduit, Schedule 80	11.258	464	338	213	123	89
Flexible metal conduit (FMC, Greenfield)	12.566	518	378	238	137	99
Liquidtight flexible metal conduit (LFMC)	12.692	523	381	240	138	100

About PVC Sch 40

Schedule 40 is the standard PVC wall. Support spacing gets wider as the size goes up (Table 352.30), and long runs in the sun need expansion fittings (352.44). See strap spacing and the fill rules.