ECN Forum Forums Code Related Discussion NEC & other Code issues To bush or not to bush PVC

Hey guys whats everyone`s interp of 352.46 then refer to 300.4f Here`s the deal wired mobil home pvc male adapter sch 80 pvc well I failed because no bushings on the pvc male adapters.Are they required in this situation? Using 4/0 quad cable direct burial. Thanks waiting for inspector to call us now as he left no reference yesterday.

PVC may be non-conductive, but its edges are still sharp enough to damage insulation.
I think that's the reason behind 300.5H.
BTW, I always call for metallic elbows in underground PVC runs because the rope that pulls in the conductors can grind an edge in a PVC elbow during a tough pull. I've had cables fail to each other on an U/G feeder for just that reason before I adopted that little trick.

Hey no rope here. Dug 10 ft ditch sch 80 down from box to proper depth direct burial cables to other end pvc to box slide wires in. But pvc fittings are beveled smooth and I don`t see how they can damage the wiring.

Did he tell you exactly what point he was concerned with? Yes, the fittings are smooth, but when you cut a piece to length, the end isn't so smooth. Is there a point where wires exit through such an opening?

You might be able to make a case that the burred end of a PVC pipe you cut with a chain saw could damage conductors but if this is the threaded end of a PVC male adapter, I don't see the issue. They are as smooth as the edges of a plastic bushing.
Both are mass produced injection molded plastic. The chance of a flaw in the process that leaves a rough edge is about the same for either.

I am very doubtful that a PVC male adaptor provides a "smoothly rounded insulated surface" as discribed in 300.4(F) and would red tag the job without even hesitating. I'm comparing it to a female adaptor with a chase nipple or a threaded hub or boss that is an integral part of an enclousure. Sorry gentlemen.

OK "the code" has spoken, (we should fail it)now has anyone actually seen a conductor damaged by a PVC fitting?

I hate to step in this one,,,


unforetally yes i did see few conductors got damaged by male termal adpator espcally after hard pull i did nick few of them [ugh !! ]

but the code required the bushing on the male adpator it been like that way for pretty long time i was not sure when it was enforeced.

I think it was debated before related with mobile home service hook up and kinda pretty common to get red flagged from this one if not carefull with bushing

Merci, Marc

I think that a male adapter requires a bushing based on this section.
Don

I looked at a few fittings and I agree. For some reason <Carlon> makes the edge sharper than it has to be, perhaps to sell more bushings. It would be quite easy to make the edge rounded to provide "equivilent protection"