I'm running feeder wires in 1-1/4" schedule 40 PVC underground to detached structure. I plan on using a 2" sleeve for the slab pour and a long 3' radius sweep elbow conduit fitting to bring wires up from the trench into the building. I was thinking of using schedule 80 for the sweep, but everyone here still uses schedule 40 for above ground transition and no one is really stocking schedule 80. Feeders will run in conduit on the surface of the wall to a surface-mounted panel. I was planning to use 1-1/4" EMT for the inside run. What transition couplings are available for this? And should I make this transition just after the schedule 40 PVC emerges from the sleeve? Other suggests for a better way to do this?
Electrical – How to Transition from Underground Schedule 40 PVC Conduit to EMT Inside Building Through Concrete Slab
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I don't know what regulations allow, but I have never seen horizontal boring done without installing the HDPE flex conduit as part of the process.
They bore by pushing the bit forward until they hit the destination. Then they swap the boring bit for a pulling end, and pull the conduit back through the hole as they are removing the drill rod. There is no separate conduit installation from the boring; you can't realistically push conduit through the bored dirt afterward.
How are you planning on doing the boring? Is this something you are going to jerry-rig yourself, or hire a company to do? If you are hiring it out, they likely will have some leftover end spool. As you say, 30 feet is a small fraction of the 2000ft spool. It should not be hard to get that as leftovers from the boring company, I would think.
And if you are doing it yourself, perhaps you can still buy some end spool offcuts from a boring company.
You want a PVC-to-threads adapter as depicted below (presumably 3/4" to match the size of the knockouts on your box, with a 1" to 3/4" PVC reducer used to adapt the LB's 1" to the adapter's 3/4").
You then use PVC from the LB to the adapter/reducer pair, and a locknut to hold the adapter to the box.
Related Topic
- Electrical – EMT or PVC Conduit For Exterior Above Ground Electrical Run
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- Concrete – Correct transition for pvc conduit to liquid tight flexible conduit on a concrete slab
- Electrical Code Compliance – Choosing Between EMT and IMC Conduit
- Wiring – Should Oversize Conduit and Grounding Wire Size be Used?
Best Answer
The most obvious options are a "conduit body" or a junction box. That also provides pulling access, which is likely useful at that point. That's what I'd do.
If you really don't need a pulling access point there (less than 360 degrees bend end to end from where you do have access) you can use a PVC to male threaded transition, a threaded coupling female to female, and an EMT to male threaded fitting. I have my doubts about it, but technically it works.