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Sizing Electrical Conduit - DieselDennis - 03-09-2017
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.
RE: Sizing Electrical Conduit - TDKPE - 03-09-2017
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.
(03-09-2017, 01:29 PM)DieselDennis Wrote: 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.
RE: Sizing Electrical Conduit - Foggy - 03-09-2017
Might just as well go to 2". A lot easier to pull wires. Add a pull wire for future "just in case".