Sizing Electrical Conduit

[DieselDennis]

Any electricians in the house?  Need to size some PVC conduit.

Going to start at a pull box against the house.  Go down 5' then to a sweeping elbow.  Then straight for 40' to another sweeping elbow.  Then up 2'. 

Plan on pulling three or four #4 coppers.  Not sure how many yet.  Haven't asked that question to the city inspector. 

What size is the minimum?  I'll likely go up a size.

[TDKPE]

Looks like 1-1/4" Schedule 80 minimum, good for up to six 4-gauge THHN/THWN or XHHW conductors.  You need Sch. 80 where it comes out of the ground.

And you don't need the equipment ground to be as large as the phase conductors; it depends on the size of the overcurrent protection for those phase conductors, though.  8-gauge copper equipment grounding conductor is good to 100A circuit ampacity.  That's all assuming this is a feeder to a subpanel or load, not service conductors to a dwelling unit.

Plan on pulling three or four #4 coppers.  Not sure how many yet.  Haven't asked that question to the city inspector.

If it's a feeder to an outbuilding, the requirement for 4 conductors has been in place since I believe the 1996 cycle, so it's unlikely your AHJ is working to an older book, one which allowed 3-wire feeders.  And either way, you'd need a grounding electrode system, usually two ground rods driven vertically full depth, 6 ft or more apart.

Subpanels within the same building have needed 4 conductors for as far back as I know, at least on grounded systems.

[Foggy]

Might just as well go to 2". A lot easier to pull wires. Add a pull wire for future "just in case".